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  • String 类 源码

    /*
     * @(#)String.java	1.204 06/06/09
     *
     * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
     * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
     */
    
    package java.lang;
    
    import java.io.ObjectStreamClass;
    import java.io.ObjectStreamField;
    import java.io.UnsupportedEncodingException;
    import java.nio.charset.Charset;
    import java.util.ArrayList;
    import java.util.Arrays;
    import java.util.Comparator;
    import java.util.Formatter;
    import java.util.Locale;
    import java.util.regex.Matcher;
    import java.util.regex.Pattern;
    import java.util.regex.PatternSyntaxException;
    
    
    /**
     * The <code>String</code> class represents character strings. All
     * string literals in Java programs, such as <code>"abc"</code>, are
     * implemented as instances of this class.
     * <p>
     * Strings are constant; their values cannot be changed after they
     * are created. String buffers support mutable strings.
     * Because String objects are immutable they can be shared. For example:
     * <p><blockquote><pre>
     *     String str = "abc";
     * </pre></blockquote><p>
     * is equivalent to:
     * <p><blockquote><pre>
     *     char data[] = {'a', 'b', 'c'};
     *     String str = new String(data);
     * </pre></blockquote><p>
     * Here are some more examples of how strings can be used:
     * <p><blockquote><pre>
     *     System.out.println("abc");
     *     String cde = "cde";
     *     System.out.println("abc" + cde);
     *     String c = "abc".substring(2,3);
     *     String d = cde.substring(1, 2);
     * </pre></blockquote>
     * <p>
     * The class <code>String</code> includes methods for examining
     * individual characters of the sequence, for comparing strings, for
     * searching strings, for extracting substrings, and for creating a
     * copy of a string with all characters translated to uppercase or to
     * lowercase. Case mapping is based on the Unicode Standard version
     * specified by the {@link java.lang.Character Character} class.
     * <p>
     * The Java language provides special support for the string
     * concatenation operator ( + ), and for conversion of
     * other objects to strings. String concatenation is implemented
     * through the <code>StringBuilder</code>(or <code>StringBuffer</code>)
     * class and its <code>append</code> method.
     * String conversions are implemented through the method
     * <code>toString</code>, defined by <code>Object</code> and
     * inherited by all classes in Java. For additional information on
     * string concatenation and conversion, see Gosling, Joy, and Steele,
     * <i>The Java Language Specification</i>.
     *
     * <p> Unless otherwise noted, passing a <tt>null</tt> argument to a constructor
     * or method in this class will cause a {@link NullPointerException} to be
     * thrown.
     *
     * <p>A <code>String</code> represents a string in the UTF-16 format
     * in which <em>supplementary characters</em> are represented by <em>surrogate
     * pairs</em> (see the section <a href="Character.html#unicode">Unicode
     * Character Representations</a> in the <code>Character</code> class for
     * more information).
     * Index values refer to <code>char</code> code units, so a supplementary
     * character uses two positions in a <code>String</code>.
     * <p>The <code>String</code> class provides methods for dealing with
     * Unicode code points (i.e., characters), in addition to those for
     * dealing with Unicode code units (i.e., <code>char</code> values).
     *
     * @author  Lee Boynton
     * @author  Arthur van Hoff
     * @version 1.204, 06/09/06
     * @see     java.lang.Object#toString()
     * @see     java.lang.StringBuffer
     * @see     java.lang.StringBuilder
     * @see     java.nio.charset.Charset
     * @since   JDK1.0
     */
    
    public final class String
        implements java.io.Serializable, Comparable<String>, CharSequence
    {
        /** The value is used for character storage. */
        private final char value[];
    
        /** The offset is the first index of the storage that is used. */
        private final int offset;
    
        /** The count is the number of characters in the String. */
        private final int count;
    
        /** Cache the hash code for the string */
        private int hash; // Default to 0
    
        /** use serialVersionUID from JDK 1.0.2 for interoperability */
        private static final long serialVersionUID = -6849794470754667710L;
    
        /**
         * Class String is special cased within the Serialization Stream Protocol.
         *
         * A String instance is written initially into an ObjectOutputStream in the
         * following format:
         * <pre>
         *      <code>TC_STRING</code> (utf String)
         * </pre>
         * The String is written by method <code>DataOutput.writeUTF</code>.
         * A new handle is generated to  refer to all future references to the
         * string instance within the stream.
         */
        private static final ObjectStreamField[] serialPersistentFields =
            new ObjectStreamField[0];
    
        /**
         * Initializes a newly created {@code String} object so that it represents
         * an empty character sequence.  Note that use of this constructor is
         * unnecessary since Strings are immutable.
         */
        public String() {
    	this.offset = 0;
    	this.count = 0;
    	this.value = new char[0];
        }
    
        /**
         * Initializes a newly created {@code String} object so that it represents
         * the same sequence of characters as the argument; in other words, the
         * newly created string is a copy of the argument string. Unless an
         * explicit copy of {@code original} is needed, use of this constructor is
         * unnecessary since Strings are immutable.
         *
         * @param  original
         *         A {@code String}
         */
        public String(String original) {
    	int size = original.count;
    	char[] originalValue = original.value;
    	char[] v;
      	if (originalValue.length > size) {
     	    // The array representing the String is bigger than the new
     	    // String itself.  Perhaps this constructor is being called
     	    // in order to trim the baggage, so make a copy of the array.
                int off = original.offset;
                v = Arrays.copyOfRange(originalValue, off, off+size);
     	} else {
     	    // The array representing the String is the same
     	    // size as the String, so no point in making a copy.
    	    v = originalValue;
     	}
    	this.offset = 0;
    	this.count = size;
    	this.value = v;
        }
    
        /**
         * Allocates a new {@code String} so that it represents the sequence of
         * characters currently contained in the character array argument. The
         * contents of the character array are copied; subsequent modification of
         * the character array does not affect the newly created string.
         *
         * @param  value
         *         The initial value of the string
         */
        public String(char value[]) {
    	int size = value.length;
    	this.offset = 0;
    	this.count = size;
    	this.value = Arrays.copyOf(value, size);
        }
    
        /**
         * Allocates a new {@code String} that contains characters from a subarray
         * of the character array argument. The {@code offset} argument is the
         * index of the first character of the subarray and the {@code count}
         * argument specifies the length of the subarray. The contents of the
         * subarray are copied; subsequent modification of the character array does
         * not affect the newly created string.
         *
         * @param  value
         *         Array that is the source of characters
         *
         * @param  offset
         *         The initial offset
         *
         * @param  count
         *         The length
         *
         * @throws  IndexOutOfBoundsException
         *          If the {@code offset} and {@code count} arguments index
         *          characters outside the bounds of the {@code value} array
         */
        public String(char value[], int offset, int count) {
            if (offset < 0) {
                throw new StringIndexOutOfBoundsException(offset);
            }
            if (count < 0) {
                throw new StringIndexOutOfBoundsException(count);
            }
            // Note: offset or count might be near -1>>>1.
            if (offset > value.length - count) {
                throw new StringIndexOutOfBoundsException(offset + count);
            }
            this.offset = 0;
            this.count = count;
            this.value = Arrays.copyOfRange(value, offset, offset+count);
        }
    
        /**
         * Allocates a new {@code String} that contains characters from a subarray
         * of the Unicode code point array argument. The {@code offset} argument
         * is the index of the first code point of the subarray and the
         * {@code count} argument specifies the length of the subarray. The
         * contents of the subarray are converted to {@code char}s; subsequent
         * modification of the {@code int} array does not affect the newly created
         * string.
         *
         * @param  codePoints
         *         Array that is the source of Unicode code points
         *
         * @param  offset
         *         The initial offset
         *
         * @param  count
         *         The length
         *
         * @throws  IllegalArgumentException
         *          If any invalid Unicode code point is found in {@code
         *          codePoints}
         *
         * @throws  IndexOutOfBoundsException
         *          If the {@code offset} and {@code count} arguments index
         *          characters outside the bounds of the {@code codePoints} array
         *
         * @since  1.5
         */
        public String(int[] codePoints, int offset, int count) {
            if (offset < 0) {
                throw new StringIndexOutOfBoundsException(offset);
            }
            if (count < 0) {
                throw new StringIndexOutOfBoundsException(count);
            }
            // Note: offset or count might be near -1>>>1.
            if (offset > codePoints.length - count) {
                throw new StringIndexOutOfBoundsException(offset + count);
            }
    
    	int expansion = 0;
    	int margin = 1;
    	char[] v = new char[count + margin];
    	int x = offset;
    	int j = 0;
    	for (int i = 0; i < count; i++) {
    	    int c = codePoints[x++];
    	    if (c < 0) {
    		throw new IllegalArgumentException();
    	    }
    	    if (margin <= 0 && (j+1) >= v.length) {
    		if (expansion == 0) {
    		    expansion = (((-margin + 1) * count) << 10) / i;
    		    expansion >>= 10;
    		    if (expansion <= 0) {
    			expansion = 1;
    		    }
    		} else {
    		    expansion *= 2;
    		}
                    int newLen = Math.min(v.length+expansion, count*2);
    		margin = (newLen - v.length) - (count - i);
                    v = Arrays.copyOf(v, newLen);
    	    }
    	    if (c < Character.MIN_SUPPLEMENTARY_CODE_POINT) {
    		v[j++] = (char) c;
    	    } else if (c <= Character.MAX_CODE_POINT) {
    		Character.toSurrogates(c, v, j);
    		j += 2;
    		margin--;
    	    } else {
    		throw new IllegalArgumentException();
    	    }
    	}
    	this.offset = 0;
    	this.value = v;
    	this.count = j;
        }
    
        /**
         * Allocates a new {@code String} constructed from a subarray of an array
         * of 8-bit integer values.
         *
         * <p> The {@code offset} argument is the index of the first byte of the
         * subarray, and the {@code count} argument specifies the length of the
         * subarray.
         *
         * <p> Each {@code byte} in the subarray is converted to a {@code char} as
         * specified in the method above.
         *
         * @deprecated This method does not properly convert bytes into characters.
         * As of JDK 1.1, the preferred way to do this is via the
         * {@code String} constructors that take a {@link
         * java.nio.charset.Charset}, charset name, or that use the platform's
         * default charset.
         *
         * @param  ascii
         *         The bytes to be converted to characters
         *
         * @param  hibyte
         *         The top 8 bits of each 16-bit Unicode code unit
         *
         * @param  offset
         *         The initial offset
         * @param  count
         *         The length
         *
         * @throws  IndexOutOfBoundsException
         *          If the {@code offset} or {@code count} argument is invalid
         *
         * @see  #String(byte[], int)
         * @see  #String(byte[], int, int, java.lang.String)
         * @see  #String(byte[], int, int, java.nio.charset.Charset)
         * @see  #String(byte[], int, int)
         * @see  #String(byte[], java.lang.String)
         * @see  #String(byte[], java.nio.charset.Charset)
         * @see  #String(byte[])
         */
        @Deprecated
        public String(byte ascii[], int hibyte, int offset, int count) {
    	checkBounds(ascii, offset, count);
            char value[] = new char[count];
    
            if (hibyte == 0) {
                for (int i = count ; i-- > 0 ;) {
                    value[i] = (char) (ascii[i + offset] & 0xff);
                }
            } else {
                hibyte <<= 8;
                for (int i = count ; i-- > 0 ;) {
                    value[i] = (char) (hibyte | (ascii[i + offset] & 0xff));
                }
            }
    	this.offset = 0;
    	this.count = count;
    	this.value = value;
        }
    
        /**
         * Allocates a new {@code String} containing characters constructed from
         * an array of 8-bit integer values. Each character <i>c</i>in the
         * resulting string is constructed from the corresponding component
         * <i>b</i> in the byte array such that:
         *
         * <blockquote><pre>
         *     <b><i>c</i></b> == (char)(((hibyte & 0xff) << 8)
         *                         | (<b><i>b</i></b> & 0xff))
         * </pre></blockquote>
         *
         * @deprecated  This method does not properly convert bytes into
         * characters.  As of JDK 1.1, the preferred way to do this is via the
         * {@code String} constructors that take a {@link
         * java.nio.charset.Charset}, charset name, or that use the platform's
         * default charset.
         *
         * @param  ascii
         *         The bytes to be converted to characters
         *
         * @param  hibyte
         *         The top 8 bits of each 16-bit Unicode code unit
         *
         * @see  #String(byte[], int, int, java.lang.String)
         * @see  #String(byte[], int, int, java.nio.charset.Charset)
         * @see  #String(byte[], int, int)
         * @see  #String(byte[], java.lang.String)
         * @see  #String(byte[], java.nio.charset.Charset)
         * @see  #String(byte[])
         */
        @Deprecated
        public String(byte ascii[], int hibyte) {
            this(ascii, hibyte, 0, ascii.length);
        }
    
        /* Common private utility method used to bounds check the byte array
         * and requested offset & length values used by the String(byte[],..)
         * constructors.
         */
        private static void checkBounds(byte[] bytes, int offset, int length) {
    	if (length < 0)
    	    throw new StringIndexOutOfBoundsException(length);
    	if (offset < 0)
    	    throw new StringIndexOutOfBoundsException(offset);
    	if (offset > bytes.length - length)
    	    throw new StringIndexOutOfBoundsException(offset + length);
        }
    
        /**
         * Constructs a new {@code String} by decoding the specified subarray of
         * bytes using the specified charset.  The length of the new {@code String}
         * is a function of the charset, and hence may not be equal to the length
         * of the subarray.
         *
         * <p> The behavior of this constructor when the given bytes are not valid
         * in the given charset is unspecified.  The {@link
         * java.nio.charset.CharsetDecoder} class should be used when more control
         * over the decoding process is required.
         *
         * @param  bytes
         *         The bytes to be decoded into characters
         *
         * @param  offset
         *         The index of the first byte to decode
         *
         * @param  length
         *         The number of bytes to decode
    
         * @param  charsetName
         *         The name of a supported {@linkplain java.nio.charset.Charset
         *         charset}
         *
         * @throws  UnsupportedEncodingException
         *          If the named charset is not supported
         *
         * @throws  IndexOutOfBoundsException
         *          If the {@code offset} and {@code length} arguments index
         *          characters outside the bounds of the {@code bytes} array
         *
         * @since  JDK1.1
         */
        public String(byte bytes[], int offset, int length, String charsetName)
    	throws UnsupportedEncodingException
        {
    	if (charsetName == null)
    	    throw new NullPointerException("charsetName");
    	checkBounds(bytes, offset, length);
    	char[] v = StringCoding.decode(charsetName, bytes, offset, length);
    	this.offset = 0;
    	this.count = v.length;
    	this.value = v;
        }
    
        /**
         * Constructs a new {@code String} by decoding the specified subarray of
         * bytes using the specified {@linkplain java.nio.charset.Charset charset}.
         * The length of the new {@code String} is a function of the charset, and
         * hence may not be equal to the length of the subarray.
         *
         * <p> This method always replaces malformed-input and unmappable-character
         * sequences with this charset's default replacement string.  The {@link
         * java.nio.charset.CharsetDecoder} class should be used when more control
         * over the decoding process is required.
         *
         * @param  bytes
         *         The bytes to be decoded into characters
         *
         * @param  offset
         *         The index of the first byte to decode
         *
         * @param  length
         *         The number of bytes to decode
         *
         * @param  charset
         *         The {@linkplain java.nio.charset.Charset charset} to be used to
         *         decode the {@code bytes}
         *
         * @throws  IndexOutOfBoundsException
         *          If the {@code offset} and {@code length} arguments index
         *          characters outside the bounds of the {@code bytes} array
         *
         * @since  1.6
         */
        public String(byte bytes[], int offset, int length, Charset charset) {
    	if (charset == null)
    	    throw new NullPointerException("charset");
    	checkBounds(bytes, offset, length);
    	char[] v = StringCoding.decode(charset, bytes, offset, length);
    	this.offset = 0;
    	this.count = v.length;
    	this.value = v;
        }
    
        /**
         * Constructs a new {@code String} by decoding the specified array of bytes
         * using the specified {@linkplain java.nio.charset.Charset charset}.  The
         * length of the new {@code String} is a function of the charset, and hence
         * may not be equal to the length of the byte array.
         *
         * <p> The behavior of this constructor when the given bytes are not valid
         * in the given charset is unspecified.  The {@link
         * java.nio.charset.CharsetDecoder} class should be used when more control
         * over the decoding process is required.
         *
         * @param  bytes
         *         The bytes to be decoded into characters
         *
         * @param  charsetName
         *         The name of a supported {@linkplain java.nio.charset.Charset
         *         charset}
         *
         * @throws  UnsupportedEncodingException
         *          If the named charset is not supported
         *
         * @since  JDK1.1
         */
        public String(byte bytes[], String charsetName)
    	throws UnsupportedEncodingException
        {
    	this(bytes, 0, bytes.length, charsetName);
        }
    
        /**
         * Constructs a new {@code String} by decoding the specified array of
         * bytes using the specified {@linkplain java.nio.charset.Charset charset}.
         * The length of the new {@code String} is a function of the charset, and
         * hence may not be equal to the length of the byte array.
         *
         * <p> This method always replaces malformed-input and unmappable-character
         * sequences with this charset's default replacement string.  The {@link
         * java.nio.charset.CharsetDecoder} class should be used when more control
         * over the decoding process is required.
         *
         * @param  bytes
         *         The bytes to be decoded into characters
         *
         * @param  charset
         *         The {@linkplain java.nio.charset.Charset charset} to be used to
         *         decode the {@code bytes}
         *
         * @since  1.6
         */
        public String(byte bytes[], Charset charset) {
    	this(bytes, 0, bytes.length, charset);
        }
    
        /**
         * Constructs a new {@code String} by decoding the specified subarray of
         * bytes using the platform's default charset.  The length of the new
         * {@code String} is a function of the charset, and hence may not be equal
         * to the length of the subarray.
         *
         * <p> The behavior of this constructor when the given bytes are not valid
         * in the default charset is unspecified.  The {@link
         * java.nio.charset.CharsetDecoder} class should be used when more control
         * over the decoding process is required.
         *
         * @param  bytes
         *         The bytes to be decoded into characters
         *
         * @param  offset
         *         The index of the first byte to decode
         *
         * @param  length
         *         The number of bytes to decode
         *
         * @throws  IndexOutOfBoundsException
         *          If the {@code offset} and the {@code length} arguments index
         *          characters outside the bounds of the {@code bytes} array
         *
         * @since  JDK1.1
         */
        public String(byte bytes[], int offset, int length) {
    	checkBounds(bytes, offset, length);
    	char[] v  = StringCoding.decode(bytes, offset, length);
    	this.offset = 0;
    	this.count = v.length;
    	this.value = v;
        }
    
        /**
         * Constructs a new {@code String} by decoding the specified array of bytes
         * using the platform's default charset.  The length of the new {@code
         * String} is a function of the charset, and hence may not be equal to the
         * length of the byte array.
         *
         * <p> The behavior of this constructor when the given bytes are not valid
         * in the default charset is unspecified.  The {@link
         * java.nio.charset.CharsetDecoder} class should be used when more control
         * over the decoding process is required.
         *
         * @param  bytes
         *         The bytes to be decoded into characters
         *
         * @since  JDK1.1
         */
        public String(byte bytes[]) {
    	this(bytes, 0, bytes.length);
        }
    
        /**
         * Allocates a new string that contains the sequence of characters
         * currently contained in the string buffer argument. The contents of the
         * string buffer are copied; subsequent modification of the string buffer
         * does not affect the newly created string.
         *
         * @param  buffer
         *         A {@code StringBuffer}
         */
        public String(StringBuffer buffer) {
            String result = buffer.toString();
            this.value = result.value;
            this.count = result.count;
            this.offset = result.offset;
        }
    
        /**
         * Allocates a new string that contains the sequence of characters
         * currently contained in the string builder argument. The contents of the
         * string builder are copied; subsequent modification of the string builder
         * does not affect the newly created string.
         *
         * <p> This constructor is provided to ease migration to {@code
         * StringBuilder}. Obtaining a string from a string builder via the {@code
         * toString} method is likely to run faster and is generally preferred.
         *
         * @param   builder
         *          A {@code StringBuilder}
         *
         * @since  1.5
         */
        public String(StringBuilder builder) {
            String result = builder.toString();
            this.value = result.value;
            this.count = result.count;
            this.offset = result.offset;
        }
    
    
        // Package private constructor which shares value array for speed.
        String(int offset, int count, char value[]) {
    	this.value = value;
    	this.offset = offset;
    	this.count = count;
        }
    
        /**
         * Returns the length of this string.
         * The length is equal to the number of <a href="Character.html#unicode">Unicode
         * code units</a> in the string.
         *
         * @return  the length of the sequence of characters represented by this
         *          object.
         */
        public int length() {
            return count;
        }
    
        /**
         * Returns <tt>true</tt> if, and only if, {@link #length()} is <tt>0</tt>.
         *
         * @return <tt>true</tt> if {@link #length()} is <tt>0</tt>, otherwise
         * <tt>false</tt>
         *
         * @since 1.6
         */
        public boolean isEmpty() {
    	return count == 0;
        }
    
        /**
         * Returns the <code>char</code> value at the
         * specified index. An index ranges from <code>0</code> to
         * <code>length() - 1</code>. The first <code>char</code> value of the sequence
         * is at index <code>0</code>, the next at index <code>1</code>,
         * and so on, as for array indexing.
         *
         * <p>If the <code>char</code> value specified by the index is a
         * <a href="Character.html#unicode">surrogate</a>, the surrogate
         * value is returned.
         *
         * @param      index   the index of the <code>char</code> value.
         * @return     the <code>char</code> value at the specified index of this string.
         *             The first <code>char</code> value is at index <code>0</code>.
         * @exception  IndexOutOfBoundsException  if the <code>index</code>
         *             argument is negative or not less than the length of this
         *             string.
         */
        public char charAt(int index) {
            if ((index < 0) || (index >= count)) {
                throw new StringIndexOutOfBoundsException(index);
            }
            return value[index + offset];
        }
    
        /**
         * Returns the character (Unicode code point) at the specified
         * index. The index refers to <code>char</code> values
         * (Unicode code units) and ranges from <code>0</code> to
         * {@link #length()}<code> - 1</code>.
         *
         * <p> If the <code>char</code> value specified at the given index
         * is in the high-surrogate range, the following index is less
         * than the length of this <code>String</code>, and the
         * <code>char</code> value at the following index is in the
         * low-surrogate range, then the supplementary code point
         * corresponding to this surrogate pair is returned. Otherwise,
         * the <code>char</code> value at the given index is returned.
         *
         * @param      index the index to the <code>char</code> values
         * @return     the code point value of the character at the
         *             <code>index</code>
         * @exception  IndexOutOfBoundsException  if the <code>index</code>
         *             argument is negative or not less than the length of this
         *             string.
         * @since      1.5
         */
        public int codePointAt(int index) {
            if ((index < 0) || (index >= count)) {
                throw new StringIndexOutOfBoundsException(index);
            }
            return Character.codePointAtImpl(value, offset + index, offset + count);
        }
    
        /**
         * Returns the character (Unicode code point) before the specified
         * index. The index refers to <code>char</code> values
         * (Unicode code units) and ranges from <code>1</code> to {@link
         * CharSequence#length() length}.
         *
         * <p> If the <code>char</code> value at <code>(index - 1)</code>
         * is in the low-surrogate range, <code>(index - 2)</code> is not
         * negative, and the <code>char</code> value at <code>(index -
         * 2)</code> is in the high-surrogate range, then the
         * supplementary code point value of the surrogate pair is
         * returned. If the <code>char</code> value at <code>index -
         * 1</code> is an unpaired low-surrogate or a high-surrogate, the
         * surrogate value is returned.
         *
         * @param     index the index following the code point that should be returned
         * @return    the Unicode code point value before the given index.
         * @exception IndexOutOfBoundsException if the <code>index</code>
         *            argument is less than 1 or greater than the length
         *            of this string.
         * @since     1.5
         */
        public int codePointBefore(int index) {
    	int i = index - 1;
            if ((i < 0) || (i >= count)) {
                throw new StringIndexOutOfBoundsException(index);
            }
            return Character.codePointBeforeImpl(value, offset + index, offset);
        }
    
        /**
         * Returns the number of Unicode code points in the specified text
         * range of this <code>String</code>. The text range begins at the
         * specified <code>beginIndex</code> and extends to the
         * <code>char</code> at index <code>endIndex - 1</code>. Thus the
         * length (in <code>char</code>s) of the text range is
         * <code>endIndex-beginIndex</code>. Unpaired surrogates within
         * the text range count as one code point each.
         *
         * @param beginIndex the index to the first <code>char</code> of
         * the text range.
         * @param endIndex the index after the last <code>char</code> of
         * the text range.
         * @return the number of Unicode code points in the specified text
         * range
         * @exception IndexOutOfBoundsException if the
         * <code>beginIndex</code> is negative, or <code>endIndex</code>
         * is larger than the length of this <code>String</code>, or
         * <code>beginIndex</code> is larger than <code>endIndex</code>.
         * @since  1.5
         */
        public int codePointCount(int beginIndex, int endIndex) {
    	if (beginIndex < 0 || endIndex > count || beginIndex > endIndex) {
    	    throw new IndexOutOfBoundsException();
    	}
    	return Character.codePointCountImpl(value, offset+beginIndex, endIndex-beginIndex);
        }
    
        /**
         * Returns the index within this <code>String</code> that is
         * offset from the given <code>index</code> by
         * <code>codePointOffset</code> code points. Unpaired surrogates
         * within the text range given by <code>index</code> and
         * <code>codePointOffset</code> count as one code point each.
         *
         * @param index the index to be offset
         * @param codePointOffset the offset in code points
         * @return the index within this <code>String</code>
         * @exception IndexOutOfBoundsException if <code>index</code>
         *   is negative or larger then the length of this
         *   <code>String</code>, or if <code>codePointOffset</code> is positive
         *   and the substring starting with <code>index</code> has fewer
         *   than <code>codePointOffset</code> code points,
         *   or if <code>codePointOffset</code> is negative and the substring
         *   before <code>index</code> has fewer than the absolute value
         *   of <code>codePointOffset</code> code points.
         * @since 1.5
         */
        public int offsetByCodePoints(int index, int codePointOffset) {
    	if (index < 0 || index > count) {
    	    throw new IndexOutOfBoundsException();
    	}
    	return Character.offsetByCodePointsImpl(value, offset, count,
    						offset+index, codePointOffset) - offset;
        }
    
        /**
         * Copy characters from this string into dst starting at dstBegin.
         * This method doesn't perform any range checking.
         */
        void getChars(char dst[], int dstBegin) {
            System.arraycopy(value, offset, dst, dstBegin, count);
        }
    
        /**
         * Copies characters from this string into the destination character
         * array.
         * <p>
         * The first character to be copied is at index <code>srcBegin</code>;
         * the last character to be copied is at index <code>srcEnd-1</code>
         * (thus the total number of characters to be copied is
         * <code>srcEnd-srcBegin</code>). The characters are copied into the
         * subarray of <code>dst</code> starting at index <code>dstBegin</code>
         * and ending at index:
         * <p><blockquote><pre>
         *     dstbegin + (srcEnd-srcBegin) - 1
         * </pre></blockquote>
         *
         * @param      srcBegin   index of the first character in the string
         *                        to copy.
         * @param      srcEnd     index after the last character in the string
         *                        to copy.
         * @param      dst        the destination array.
         * @param      dstBegin   the start offset in the destination array.
         * @exception IndexOutOfBoundsException If any of the following
         *            is true:
         *            <ul><li><code>srcBegin</code> is negative.
         *            <li><code>srcBegin</code> is greater than <code>srcEnd</code>
         *            <li><code>srcEnd</code> is greater than the length of this
         *                string
         *            <li><code>dstBegin</code> is negative
         *            <li><code>dstBegin+(srcEnd-srcBegin)</code> is larger than
         *                <code>dst.length</code></ul>
         */
        public void getChars(int srcBegin, int srcEnd, char dst[], int dstBegin) {
            if (srcBegin < 0) {
                throw new StringIndexOutOfBoundsException(srcBegin);
            }
            if (srcEnd > count) {
                throw new StringIndexOutOfBoundsException(srcEnd);
            }
            if (srcBegin > srcEnd) {
                throw new StringIndexOutOfBoundsException(srcEnd - srcBegin);
            }
            System.arraycopy(value, offset + srcBegin, dst, dstBegin,
                 srcEnd - srcBegin);
        }
    
        /**
         * Copies characters from this string into the destination byte array. Each
         * byte receives the 8 low-order bits of the corresponding character. The
         * eight high-order bits of each character are not copied and do not
         * participate in the transfer in any way.
         *
         * <p> The first character to be copied is at index {@code srcBegin}; the
         * last character to be copied is at index {@code srcEnd-1}.  The total
         * number of characters to be copied is {@code srcEnd-srcBegin}. The
         * characters, converted to bytes, are copied into the subarray of {@code
         * dst} starting at index {@code dstBegin} and ending at index:
         *
         * <blockquote><pre>
         *     dstbegin + (srcEnd-srcBegin) - 1
         * </pre></blockquote>
         *
         * @deprecated  This method does not properly convert characters into
         * bytes.  As of JDK 1.1, the preferred way to do this is via the
         * {@link #getBytes()} method, which uses the platform's default charset.
         *
         * @param  srcBegin
         *         Index of the first character in the string to copy
         *
         * @param  srcEnd
         *         Index after the last character in the string to copy
         *
         * @param  dst
         *         The destination array
         *
         * @param  dstBegin
         *         The start offset in the destination array
         *
         * @throws  IndexOutOfBoundsException
         *          If any of the following is true:
         *          <ul>
         *            <li> {@code srcBegin} is negative
         *            <li> {@code srcBegin} is greater than {@code srcEnd}
         *            <li> {@code srcEnd} is greater than the length of this String
         *            <li> {@code dstBegin} is negative
         *            <li> {@code dstBegin+(srcEnd-srcBegin)} is larger than {@code
         *                 dst.length}
         *          </ul>
         */
        @Deprecated
        public void getBytes(int srcBegin, int srcEnd, byte dst[], int dstBegin) {
            if (srcBegin < 0) {
                throw new StringIndexOutOfBoundsException(srcBegin);
            }
            if (srcEnd > count) {
                throw new StringIndexOutOfBoundsException(srcEnd);
            }
            if (srcBegin > srcEnd) {
                throw new StringIndexOutOfBoundsException(srcEnd - srcBegin);
            }
            int j = dstBegin;
            int n = offset + srcEnd;
            int i = offset + srcBegin;
            char[] val = value;   /* avoid getfield opcode */
    
            while (i < n) {
                dst[j++] = (byte)val[i++];
            }
        }
    
        /**
         * Encodes this {@code String} into a sequence of bytes using the named
         * charset, storing the result into a new byte array.
         *
         * <p> The behavior of this method when this string cannot be encoded in
         * the given charset is unspecified.  The {@link
         * java.nio.charset.CharsetEncoder} class should be used when more control
         * over the encoding process is required.
         *
         * @param  charsetName
         *         The name of a supported {@linkplain java.nio.charset.Charset
         *         charset}
         *
         * @return  The resultant byte array
         *
         * @throws  UnsupportedEncodingException
         *          If the named charset is not supported
         *
         * @since  JDK1.1
         */
        public byte[] getBytes(String charsetName)
    	throws UnsupportedEncodingException
        {
    	if (charsetName == null) throw new NullPointerException();
    	return StringCoding.encode(charsetName, value, offset, count);
        }
    
        /**
         * Encodes this {@code String} into a sequence of bytes using the given
         * {@linkplain java.nio.charset.Charset charset}, storing the result into a
         * new byte array.
         *
         * <p> This method always replaces malformed-input and unmappable-character
         * sequences with this charset's default replacement byte array.  The
         * {@link java.nio.charset.CharsetEncoder} class should be used when more
         * control over the encoding process is required.
         *
         * @param  charset
         *         The {@linkplain java.nio.charset.Charset} to be used to encode
         *         the {@code String}
         *
         * @return  The resultant byte array
         *
         * @since  1.6
         */
        public byte[] getBytes(Charset charset) {
    	if (charset == null) throw new NullPointerException();
    	return StringCoding.encode(charset, value, offset, count);
        }
    
        /**
         * Encodes this {@code String} into a sequence of bytes using the
         * platform's default charset, storing the result into a new byte array.
         *
         * <p> The behavior of this method when this string cannot be encoded in
         * the default charset is unspecified.  The {@link
         * java.nio.charset.CharsetEncoder} class should be used when more control
         * over the encoding process is required.
         *
         * @return  The resultant byte array
         *
         * @since      JDK1.1
         */
        public byte[] getBytes() {
    	return StringCoding.encode(value, offset, count);
        }
    
        /**
         * Compares this string to the specified object.  The result is {@code
         * true} if and only if the argument is not {@code null} and is a {@code
         * String} object that represents the same sequence of characters as this
         * object.
         *
         * @param  anObject
         *         The object to compare this {@code String} against
         *
         * @return  {@code true} if the given object represents a {@code String}
         *          equivalent to this string, {@code false} otherwise
         *
         * @see  #compareTo(String)
         * @see  #equalsIgnoreCase(String)
         */
        public boolean equals(Object anObject) {
    	if (this == anObject) {
    	    return true;
    	}
    	if (anObject instanceof String) {
    	    String anotherString = (String)anObject;
    	    int n = count;
    	    if (n == anotherString.count) {
    		char v1[] = value;
    		char v2[] = anotherString.value;
    		int i = offset;
    		int j = anotherString.offset;
    		while (n-- != 0) {
    		    if (v1[i++] != v2[j++])
    			return false;
    		}
    		return true;
    	    }
    	}
    	return false;
        }
    
        /**
         * Compares this string to the specified {@code StringBuffer}.  The result
         * is {@code true} if and only if this {@code String} represents the same
         * sequence of characters as the specified {@code StringBuffer}.
         *
         * @param  sb
         *         The {@code StringBuffer} to compare this {@code String} against
         *
         * @return  {@code true} if this {@code String} represents the same
         *          sequence of characters as the specified {@code StringBuffer},
         *          {@code false} otherwise
         *
         * @since  1.4
         */
        public boolean contentEquals(StringBuffer sb) {
            synchronized(sb) {
                return contentEquals((CharSequence)sb);
            }
        }
    
        /**
         * Compares this string to the specified {@code CharSequence}.  The result
         * is {@code true} if and only if this {@code String} represents the same
         * sequence of char values as the specified sequence.
         *
         * @param  cs
         *         The sequence to compare this {@code String} against
         *
         * @return  {@code true} if this {@code String} represents the same
         *          sequence of char values as the specified sequence, {@code
         *          false} otherwise
         *
         * @since  1.5
         */
        public boolean contentEquals(CharSequence cs) {
            if (count != cs.length())
                return false;
            // Argument is a StringBuffer, StringBuilder
            if (cs instanceof AbstractStringBuilder) {
                char v1[] = value;
                char v2[] = ((AbstractStringBuilder)cs).getValue();
                int i = offset;
                int j = 0;
                int n = count;
                while (n-- != 0) {
                    if (v1[i++] != v2[j++])
                        return false;
                }
            }
            // Argument is a String
            if (cs.equals(this))
                return true;
            // Argument is a generic CharSequence
            char v1[] = value;
            int i = offset;
            int j = 0;
            int n = count;
            while (n-- != 0) {
                if (v1[i++] != cs.charAt(j++))
                    return false;
            }
            return true;
        }
    
        /**
         * Compares this {@code String} to another {@code String}, ignoring case
         * considerations.  Two strings are considered equal ignoring case if they
         * are of the same length and corresponding characters in the two strings
         * are equal ignoring case.
         *
         * <p> Two characters {@code c1} and {@code c2} are considered the same
         * ignoring case if at least one of the following is true:
         * <ul>
         *   <li> The two characters are the same (as compared by the
         *        {@code ==} operator)
         *   <li> Applying the method {@link
         *        java.lang.Character#toUpperCase(char)} to each character
         *        produces the same result
         *   <li> Applying the method {@link
         *        java.lang.Character#toLowerCase(char)} to each character
         *        produces the same result
         * </ul>
         *
         * @param  anotherString
         *         The {@code String} to compare this {@code String} against
         *
         * @return  {@code true} if the argument is not {@code null} and it
         *          represents an equivalent {@code String} ignoring case; {@code
         *          false} otherwise
         *
         * @see  #equals(Object)
         */
        public boolean equalsIgnoreCase(String anotherString) {
            return (this == anotherString) ? true :
                   (anotherString != null) && (anotherString.count == count) &&
    	       regionMatches(true, 0, anotherString, 0, count);
        }
    
        /**
         * Compares two strings lexicographically.
         * The comparison is based on the Unicode value of each character in
         * the strings. The character sequence represented by this
         * <code>String</code> object is compared lexicographically to the
         * character sequence represented by the argument string. The result is
         * a negative integer if this <code>String</code> object
         * lexicographically precedes the argument string. The result is a
         * positive integer if this <code>String</code> object lexicographically
         * follows the argument string. The result is zero if the strings
         * are equal; <code>compareTo</code> returns <code>0</code> exactly when
         * the {@link #equals(Object)} method would return <code>true</code>.
         * <p>
         * This is the definition of lexicographic ordering. If two strings are
         * different, then either they have different characters at some index
         * that is a valid index for both strings, or their lengths are different,
         * or both. If they have different characters at one or more index
         * positions, let <i>k</i> be the smallest such index; then the string
         * whose character at position <i>k</i> has the smaller value, as
         * determined by using the < operator, lexicographically precedes the
         * other string. In this case, <code>compareTo</code> returns the
         * difference of the two character values at position <code>k</code> in
         * the two string -- that is, the value:
         * <blockquote><pre>
         * this.charAt(k)-anotherString.charAt(k)
         * </pre></blockquote>
         * If there is no index position at which they differ, then the shorter
         * string lexicographically precedes the longer string. In this case,
         * <code>compareTo</code> returns the difference of the lengths of the
         * strings -- that is, the value:
         * <blockquote><pre>
         * this.length()-anotherString.length()
         * </pre></blockquote>
         *
         * @param   anotherString   the <code>String</code> to be compared.
         * @return  the value <code>0</code> if the argument string is equal to
         *          this string; a value less than <code>0</code> if this string
         *          is lexicographically less than the string argument; and a
         *          value greater than <code>0</code> if this string is
         *          lexicographically greater than the string argument.
         */
        public int compareTo(String anotherString) {
    	int len1 = count;
    	int len2 = anotherString.count;
    	int n = Math.min(len1, len2);
    	char v1[] = value;
    	char v2[] = anotherString.value;
    	int i = offset;
    	int j = anotherString.offset;
    
    	if (i == j) {
    	    int k = i;
    	    int lim = n + i;
    	    while (k < lim) {
    		char c1 = v1[k];
    		char c2 = v2[k];
    		if (c1 != c2) {
    		    return c1 - c2;
    		}
    		k++;
    	    }
    	} else {
    	    while (n-- != 0) {
    		char c1 = v1[i++];
    		char c2 = v2[j++];
    		if (c1 != c2) {
    		    return c1 - c2;
    		}
    	    }
    	}
    	return len1 - len2;
        }
    
        /**
         * A Comparator that orders <code>String</code> objects as by
         * <code>compareToIgnoreCase</code>. This comparator is serializable.
         * <p>
         * Note that this Comparator does <em>not</em> take locale into account,
         * and will result in an unsatisfactory ordering for certain locales.
         * The java.text package provides <em>Collators</em> to allow
         * locale-sensitive ordering.
         *
         * @see     java.text.Collator#compare(String, String)
         * @since   1.2
         */
        public static final Comparator<String> CASE_INSENSITIVE_ORDER
                                             = new CaseInsensitiveComparator();
        private static class CaseInsensitiveComparator
                             implements Comparator<String>, java.io.Serializable {
    	// use serialVersionUID from JDK 1.2.2 for interoperability
    	private static final long serialVersionUID = 8575799808933029326L;
    
            public int compare(String s1, String s2) {
                int n1=s1.length(), n2=s2.length();
                for (int i1=0, i2=0; i1<n1 && i2<n2; i1++, i2++) {
                    char c1 = s1.charAt(i1);
                    char c2 = s2.charAt(i2);
                    if (c1 != c2) {
                        c1 = Character.toUpperCase(c1);
                        c2 = Character.toUpperCase(c2);
                        if (c1 != c2) {
                            c1 = Character.toLowerCase(c1);
                            c2 = Character.toLowerCase(c2);
                            if (c1 != c2) {
                                return c1 - c2;
                            }
                        }
                    }
                }
                return n1 - n2;
            }
        }
    
        /**
         * Compares two strings lexicographically, ignoring case
         * differences. This method returns an integer whose sign is that of
         * calling <code>compareTo</code> with normalized versions of the strings
         * where case differences have been eliminated by calling
         * <code>Character.toLowerCase(Character.toUpperCase(character))</code> on
         * each character.
         * <p>
         * Note that this method does <em>not</em> take locale into account,
         * and will result in an unsatisfactory ordering for certain locales.
         * The java.text package provides <em>collators</em> to allow
         * locale-sensitive ordering.
         *
         * @param   str   the <code>String</code> to be compared.
         * @return  a negative integer, zero, or a positive integer as the
         *		specified String is greater than, equal to, or less
         *		than this String, ignoring case considerations.
         * @see     java.text.Collator#compare(String, String)
         * @since   1.2
         */
        public int compareToIgnoreCase(String str) {
            return CASE_INSENSITIVE_ORDER.compare(this, str);
        }
    
        /**
         * Tests if two string regions are equal.
         * <p>
         * A substring of this <tt>String</tt> object is compared to a substring
         * of the argument other. The result is true if these substrings
         * represent identical character sequences. The substring of this
         * <tt>String</tt> object to be compared begins at index <tt>toffset</tt>
         * and has length <tt>len</tt>. The substring of other to be compared
         * begins at index <tt>ooffset</tt> and has length <tt>len</tt>. The
         * result is <tt>false</tt> if and only if at least one of the following
         * is true:
         * <ul><li><tt>toffset</tt> is negative.
         * <li><tt>ooffset</tt> is negative.
         * <li><tt>toffset+len</tt> is greater than the length of this
         * <tt>String</tt> object.
         * <li><tt>ooffset+len</tt> is greater than the length of the other
         * argument.
         * <li>There is some nonnegative integer <i>k</i> less than <tt>len</tt>
         * such that:
         * <tt>this.charAt(toffset+<i>k</i>) != other.charAt(ooffset+<i>k</i>)</tt>
         * </ul>
         *
         * @param   toffset   the starting offset of the subregion in this string.
         * @param   other     the string argument.
         * @param   ooffset   the starting offset of the subregion in the string
         *                    argument.
         * @param   len       the number of characters to compare.
         * @return  <code>true</code> if the specified subregion of this string
         *          exactly matches the specified subregion of the string argument;
         *          <code>false</code> otherwise.
         */
        public boolean regionMatches(int toffset, String other, int ooffset,
    				 int len) {
    	char ta[] = value;
    	int to = offset + toffset;
    	char pa[] = other.value;
    	int po = other.offset + ooffset;
    	// Note: toffset, ooffset, or len might be near -1>>>1.
    	if ((ooffset < 0) || (toffset < 0) || (toffset > (long)count - len)
    	    || (ooffset > (long)other.count - len)) {
    	    return false;
    	}
    	while (len-- > 0) {
    	    if (ta[to++] != pa[po++]) {
    	        return false;
    	    }
    	}
    	return true;
        }
    
        /**
         * Tests if two string regions are equal.
         * <p>
         * A substring of this <tt>String</tt> object is compared to a substring
         * of the argument <tt>other</tt>. The result is <tt>true</tt> if these
         * substrings represent character sequences that are the same, ignoring
         * case if and only if <tt>ignoreCase</tt> is true. The substring of
         * this <tt>String</tt> object to be compared begins at index
         * <tt>toffset</tt> and has length <tt>len</tt>. The substring of
         * <tt>other</tt> to be compared begins at index <tt>ooffset</tt> and
         * has length <tt>len</tt>. The result is <tt>false</tt> if and only if
         * at least one of the following is true:
         * <ul><li><tt>toffset</tt> is negative.
         * <li><tt>ooffset</tt> is negative.
         * <li><tt>toffset+len</tt> is greater than the length of this
         * <tt>String</tt> object.
         * <li><tt>ooffset+len</tt> is greater than the length of the other
         * argument.
         * <li><tt>ignoreCase</tt> is <tt>false</tt> and there is some nonnegative
         * integer <i>k</i> less than <tt>len</tt> such that:
         * <blockquote><pre>
         * this.charAt(toffset+k) != other.charAt(ooffset+k)
         * </pre></blockquote>
         * <li><tt>ignoreCase</tt> is <tt>true</tt> and there is some nonnegative
         * integer <i>k</i> less than <tt>len</tt> such that:
         * <blockquote><pre>
         * Character.toLowerCase(this.charAt(toffset+k)) !=
                   Character.toLowerCase(other.charAt(ooffset+k))
         * </pre></blockquote>
         * and:
         * <blockquote><pre>
         * Character.toUpperCase(this.charAt(toffset+k)) !=
         *         Character.toUpperCase(other.charAt(ooffset+k))
         * </pre></blockquote>
         * </ul>
         *
         * @param   ignoreCase   if <code>true</code>, ignore case when comparing
         *                       characters.
         * @param   toffset      the starting offset of the subregion in this
         *                       string.
         * @param   other        the string argument.
         * @param   ooffset      the starting offset of the subregion in the string
         *                       argument.
         * @param   len          the number of characters to compare.
         * @return  <code>true</code> if the specified subregion of this string
         *          matches the specified subregion of the string argument;
         *          <code>false</code> otherwise. Whether the matching is exact
         *          or case insensitive depends on the <code>ignoreCase</code>
         *          argument.
         */
        public boolean regionMatches(boolean ignoreCase, int toffset,
                               String other, int ooffset, int len) {
            char ta[] = value;
            int to = offset + toffset;
            char pa[] = other.value;
            int po = other.offset + ooffset;
            // Note: toffset, ooffset, or len might be near -1>>>1.
            if ((ooffset < 0) || (toffset < 0) || (toffset > (long)count - len) ||
                    (ooffset > (long)other.count - len)) {
                return false;
            }
            while (len-- > 0) {
                char c1 = ta[to++];
                char c2 = pa[po++];
                if (c1 == c2) {
                    continue;
                }
                if (ignoreCase) {
                    // If characters don't match but case may be ignored,
                    // try converting both characters to uppercase.
                    // If the results match, then the comparison scan should
                    // continue.
                    char u1 = Character.toUpperCase(c1);
                    char u2 = Character.toUpperCase(c2);
                    if (u1 == u2) {
                        continue;
                    }
                    // Unfortunately, conversion to uppercase does not work properly
                    // for the Georgian alphabet, which has strange rules about case
                    // conversion.  So we need to make one last check before
                    // exiting.
                    if (Character.toLowerCase(u1) == Character.toLowerCase(u2)) {
                        continue;
                    }
                }
                return false;
            }
            return true;
        }
    
        /**
         * Tests if the substring of this string beginning at the
         * specified index starts with the specified prefix.
         *
         * @param   prefix    the prefix.
         * @param   toffset   where to begin looking in this string.
         * @return  <code>true</code> if the character sequence represented by the
         *          argument is a prefix of the substring of this object starting
         *          at index <code>toffset</code>; <code>false</code> otherwise.
         *          The result is <code>false</code> if <code>toffset</code> is
         *          negative or greater than the length of this
         *          <code>String</code> object; otherwise the result is the same
         *          as the result of the expression
         *          <pre>
         *          this.substring(toffset).startsWith(prefix)
         *          </pre>
         */
        public boolean startsWith(String prefix, int toffset) {
    	char ta[] = value;
    	int to = offset + toffset;
    	char pa[] = prefix.value;
    	int po = prefix.offset;
    	int pc = prefix.count;
    	// Note: toffset might be near -1>>>1.
    	if ((toffset < 0) || (toffset > count - pc)) {
    	    return false;
    	}
    	while (--pc >= 0) {
    	    if (ta[to++] != pa[po++]) {
    	        return false;
    	    }
    	}
    	return true;
        }
    
        /**
         * Tests if this string starts with the specified prefix.
         *
         * @param   prefix   the prefix.
         * @return  <code>true</code> if the character sequence represented by the
         *          argument is a prefix of the character sequence represented by
         *          this string; <code>false</code> otherwise.
         *          Note also that <code>true</code> will be returned if the
         *          argument is an empty string or is equal to this
         *          <code>String</code> object as determined by the
         *          {@link #equals(Object)} method.
         * @since   1. 0
         */
        public boolean startsWith(String prefix) {
    	return startsWith(prefix, 0);
        }
    
        /**
         * Tests if this string ends with the specified suffix.
         *
         * @param   suffix   the suffix.
         * @return  <code>true</code> if the character sequence represented by the
         *          argument is a suffix of the character sequence represented by
         *          this object; <code>false</code> otherwise. Note that the
         *          result will be <code>true</code> if the argument is the
         *          empty string or is equal to this <code>String</code> object
         *          as determined by the {@link #equals(Object)} method.
         */
        public boolean endsWith(String suffix) {
    	return startsWith(suffix, count - suffix.count);
        }
    
        /**
         * Returns a hash code for this string. The hash code for a
         * <code>String</code> object is computed as
         * <blockquote><pre>
         * s[0]*31^(n-1) + s[1]*31^(n-2) + ... + s[n-1]
         * </pre></blockquote>
         * using <code>int</code> arithmetic, where <code>s[i]</code> is the
         * <i>i</i>th character of the string, <code>n</code> is the length of
         * the string, and <code>^</code> indicates exponentiation.
         * (The hash value of the empty string is zero.)
         *
         * @return  a hash code value for this object.
         */
        public int hashCode() {
    	int h = hash;
    	if (h == 0) {
    	    int off = offset;
    	    char val[] = value;
    	    int len = count;
    
                for (int i = 0; i < len; i++) {
                    h = 31*h + val[off++];
                }
                hash = h;
            }
            return h;
        }
    
        /**
         * Returns the index within this string of the first occurrence of
         * the specified character. If a character with value
         * <code>ch</code> occurs in the character sequence represented by
         * this <code>String</code> object, then the index (in Unicode
         * code units) of the first such occurrence is returned. For
         * values of <code>ch</code> in the range from 0 to 0xFFFF
         * (inclusive), this is the smallest value <i>k</i> such that:
         * <blockquote><pre>
         * this.charAt(<i>k</i>) == ch
         * </pre></blockquote>
         * is true. For other values of <code>ch</code>, it is the
         * smallest value <i>k</i> such that:
         * <blockquote><pre>
         * this.codePointAt(<i>k</i>) == ch
         * </pre></blockquote>
         * is true. In either case, if no such character occurs in this
         * string, then <code>-1</code> is returned.
         *
         * @param   ch   a character (Unicode code point).
         * @return  the index of the first occurrence of the character in the
         *          character sequence represented by this object, or
         *          <code>-1</code> if the character does not occur.
         */
        public int indexOf(int ch) {
    	return indexOf(ch, 0);
        }
    
        /**
         * Returns the index within this string of the first occurrence of the
         * specified character, starting the search at the specified index.
         * <p>
         * If a character with value <code>ch</code> occurs in the
         * character sequence represented by this <code>String</code>
         * object at an index no smaller than <code>fromIndex</code>, then
         * the index of the first such occurrence is returned. For values
         * of <code>ch</code> in the range from 0 to 0xFFFF (inclusive),
         * this is the smallest value <i>k</i> such that:
         * <blockquote><pre>
         * (this.charAt(<i>k</i>) == ch) && (<i>k</i> >= fromIndex)
         * </pre></blockquote>
         * is true. For other values of <code>ch</code>, it is the
         * smallest value <i>k</i> such that:
         * <blockquote><pre>
         * (this.codePointAt(<i>k</i>) == ch) && (<i>k</i> >= fromIndex)
         * </pre></blockquote>
         * is true. In either case, if no such character occurs in this
         * string at or after position <code>fromIndex</code>, then
         * <code>-1</code> is returned.
         *
         * <p>
         * There is no restriction on the value of <code>fromIndex</code>. If it
         * is negative, it has the same effect as if it were zero: this entire
         * string may be searched. If it is greater than the length of this
         * string, it has the same effect as if it were equal to the length of
         * this string: <code>-1</code> is returned.
         *
         * <p>All indices are specified in <code>char</code> values
         * (Unicode code units).
         *
         * @param   ch          a character (Unicode code point).
         * @param   fromIndex   the index to start the search from.
         * @return  the index of the first occurrence of the character in the
         *          character sequence represented by this object that is greater
         *          than or equal to <code>fromIndex</code>, or <code>-1</code>
         *          if the character does not occur.
         */
        public int indexOf(int ch, int fromIndex) {
    	int max = offset + count;
    	char v[] = value;
    
    	if (fromIndex < 0) {
    	    fromIndex = 0;
    	} else if (fromIndex >= count) {
    	    // Note: fromIndex might be near -1>>>1.
    	    return -1;
    	}
    
    	int i = offset + fromIndex;
    	if (ch < Character.MIN_SUPPLEMENTARY_CODE_POINT) {
    	    // handle most cases here (ch is a BMP code point or a
    	    // negative value (invalid code point))
    	    for (; i < max ; i++) {
    		if (v[i] == ch) {
    		    return i - offset;
    		}
    	    }
    	    return -1;
    	}
    
    	if (ch <= Character.MAX_CODE_POINT) {
    	    // handle supplementary characters here
    	    char[] surrogates = Character.toChars(ch);
    	    for (; i < max; i++) {
    		if (v[i] == surrogates[0]) {
    		    if (i + 1 == max) {
    			break;
    		    }
    		    if (v[i+1] == surrogates[1]) {
    			return i - offset;
    		    }
    		}
    	    }
    	}
    	return -1;
        }
    
        /**
         * Returns the index within this string of the last occurrence of
         * the specified character. For values of <code>ch</code> in the
         * range from 0 to 0xFFFF (inclusive), the index (in Unicode code
         * units) returned is the largest value <i>k</i> such that:
         * <blockquote><pre>
         * this.charAt(<i>k</i>) == ch
         * </pre></blockquote>
         * is true. For other values of <code>ch</code>, it is the
         * largest value <i>k</i> such that:
         * <blockquote><pre>
         * this.codePointAt(<i>k</i>) == ch
         * </pre></blockquote>
         * is true.  In either case, if no such character occurs in this
         * string, then <code>-1</code> is returned.  The
         * <code>String</code> is searched backwards starting at the last
         * character.
         *
         * @param   ch   a character (Unicode code point).
         * @return  the index of the last occurrence of the character in the
         *          character sequence represented by this object, or
         *          <code>-1</code> if the character does not occur.
         */
        public int lastIndexOf(int ch) {
    	return lastIndexOf(ch, count - 1);
        }
    
        /**
         * Returns the index within this string of the last occurrence of
         * the specified character, searching backward starting at the
         * specified index. For values of <code>ch</code> in the range
         * from 0 to 0xFFFF (inclusive), the index returned is the largest
         * value <i>k</i> such that:
         * <blockquote><pre>
         * (this.charAt(<i>k</i>) == ch) && (<i>k</i> <= fromIndex)
         * </pre></blockquote>
         * is true. For other values of <code>ch</code>, it is the
         * largest value <i>k</i> such that:
         * <blockquote><pre>
         * (this.codePointAt(<i>k</i>) == ch) && (<i>k</i> <= fromIndex)
         * </pre></blockquote>
         * is true. In either case, if no such character occurs in this
         * string at or before position <code>fromIndex</code>, then
         * <code>-1</code> is returned.
         *
         * <p>All indices are specified in <code>char</code> values
         * (Unicode code units).
         *
         * @param   ch          a character (Unicode code point).
         * @param   fromIndex   the index to start the search from. There is no
         *          restriction on the value of <code>fromIndex</code>. If it is
         *          greater than or equal to the length of this string, it has
         *          the same effect as if it were equal to one less than the
         *          length of this string: this entire string may be searched.
         *          If it is negative, it has the same effect as if it were -1:
         *          -1 is returned.
         * @return  the index of the last occurrence of the character in the
         *          character sequence represented by this object that is less
         *          than or equal to <code>fromIndex</code>, or <code>-1</code>
         *          if the character does not occur before that point.
         */
        public int lastIndexOf(int ch, int fromIndex) {
    	int min = offset;
    	char v[] = value;
    
    	int i = offset + ((fromIndex >= count) ? count - 1 : fromIndex);
    
    	if (ch < Character.MIN_SUPPLEMENTARY_CODE_POINT) {
    	    // handle most cases here (ch is a BMP code point or a
    	    // negative value (invalid code point))
    	    for (; i >= min ; i--) {
    		if (v[i] == ch) {
    		    return i - offset;
    		}
    	    }
    	    return -1;
    	}
    
    	int max = offset + count;
    	if (ch <= Character.MAX_CODE_POINT) {
    	    // handle supplementary characters here
    	    char[] surrogates = Character.toChars(ch);
    	    for (; i >= min; i--) {
    		if (v[i] == surrogates[0]) {
    		    if (i + 1 == max) {
    			break;
    		    }
    		    if (v[i+1] == surrogates[1]) {
    			return i - offset;
    		    }
    		}
    	    }
    	}
    	return -1;
        }
    
        /**
         * Returns the index within this string of the first occurrence of the
         * specified substring. The integer returned is the smallest value
         * <i>k</i> such that:
         * <blockquote><pre>
         * this.startsWith(str, <i>k</i>)
         * </pre></blockquote>
         * is <code>true</code>.
         *
         * @param   str   any string.
         * @return  if the string argument occurs as a substring within this
         *          object, then the index of the first character of the first
         *          such substring is returned; if it does not occur as a
         *          substring, <code>-1</code> is returned.
         */
        public int indexOf(String str) {
    	return indexOf(str, 0);
        }
    
        /**
         * Returns the index within this string of the first occurrence of the
         * specified substring, starting at the specified index.  The integer
         * returned is the smallest value <tt>k</tt> for which:
         * <blockquote><pre>
         *     k >= Math.min(fromIndex, this.length()) && this.startsWith(str, k)
         * </pre></blockquote>
         * If no such value of <i>k</i> exists, then -1 is returned.
         *
         * @param   str         the substring for which to search.
         * @param   fromIndex   the index from which to start the search.
         * @return  the index within this string of the first occurrence of the
         *          specified substring, starting at the specified index.
         */
        public int indexOf(String str, int fromIndex) {
            return indexOf(value, offset, count,
                           str.value, str.offset, str.count, fromIndex);
        }
    
        /**
         * Code shared by String and StringBuffer to do searches. The
         * source is the character array being searched, and the target
         * is the string being searched for.
         *
         * @param   source       the characters being searched.
         * @param   sourceOffset offset of the source string.
         * @param   sourceCount  count of the source string.
         * @param   target       the characters being searched for.
         * @param   targetOffset offset of the target string.
         * @param   targetCount  count of the target string.
         * @param   fromIndex    the index to begin searching from.
         */
        static int indexOf(char[] source, int sourceOffset, int sourceCount,
                           char[] target, int targetOffset, int targetCount,
                           int fromIndex) {
    	if (fromIndex >= sourceCount) {
                return (targetCount == 0 ? sourceCount : -1);
    	}
        	if (fromIndex < 0) {
        	    fromIndex = 0;
        	}
    	if (targetCount == 0) {
    	    return fromIndex;
    	}
    
            char first  = target[targetOffset];
            int max = sourceOffset + (sourceCount - targetCount);
    
            for (int i = sourceOffset + fromIndex; i <= max; i++) {
                /* Look for first character. */
                if (source[i] != first) {
                    while (++i <= max && source[i] != first);
                }
    
                /* Found first character, now look at the rest of v2 */
                if (i <= max) {
                    int j = i + 1;
                    int end = j + targetCount - 1;
                    for (int k = targetOffset + 1; j < end && source[j] ==
                             target[k]; j++, k++);
    
                    if (j == end) {
                        /* Found whole string. */
                        return i - sourceOffset;
                    }
                }
            }
            return -1;
        }
    
        /**
         * Returns the index within this string of the rightmost occurrence
         * of the specified substring.  The rightmost empty string "" is
         * considered to occur at the index value <code>this.length()</code>.
         * The returned index is the largest value <i>k</i> such that
         * <blockquote><pre>
         * this.startsWith(str, k)
         * </pre></blockquote>
         * is true.
         *
         * @param   str   the substring to search for.
         * @return  if the string argument occurs one or more times as a substring
         *          within this object, then the index of the first character of
         *          the last such substring is returned. If it does not occur as
         *          a substring, <code>-1</code> is returned.
         */
        public int lastIndexOf(String str) {
    	return lastIndexOf(str, count);
        }
    
        /**
         * Returns the index within this string of the last occurrence of the
         * specified substring, searching backward starting at the specified index.
         * The integer returned is the largest value <i>k</i> such that:
         * <blockquote><pre>
         *     k <= Math.min(fromIndex, this.length()) && this.startsWith(str, k)
         * </pre></blockquote>
         * If no such value of <i>k</i> exists, then -1 is returned.
         *
         * @param   str         the substring to search for.
         * @param   fromIndex   the index to start the search from.
         * @return  the index within this string of the last occurrence of the
         *          specified substring.
         */
        public int lastIndexOf(String str, int fromIndex) {
            return lastIndexOf(value, offset, count,
                               str.value, str.offset, str.count, fromIndex);
        }
    
        /**
         * Code shared by String and StringBuffer to do searches. The
         * source is the character array being searched, and the target
         * is the string being searched for.
         *
         * @param   source       the characters being searched.
         * @param   sourceOffset offset of the source string.
         * @param   sourceCount  count of the source string.
         * @param   target       the characters being searched for.
         * @param   targetOffset offset of the target string.
         * @param   targetCount  count of the target string.
         * @param   fromIndex    the index to begin searching from.
         */
        static int lastIndexOf(char[] source, int sourceOffset, int sourceCount,
                               char[] target, int targetOffset, int targetCount,
                               int fromIndex) {
            /*
    	 * Check arguments; return immediately where possible. For
    	 * consistency, don't check for null str.
    	 */
            int rightIndex = sourceCount - targetCount;
    	if (fromIndex < 0) {
    	    return -1;
    	}
    	if (fromIndex > rightIndex) {
    	    fromIndex = rightIndex;
    	}
    	/* Empty string always matches. */
    	if (targetCount == 0) {
    	    return fromIndex;
    	}
    
            int strLastIndex = targetOffset + targetCount - 1;
    	char strLastChar = target[strLastIndex];
    	int min = sourceOffset + targetCount - 1;
    	int i = min + fromIndex;
    
        startSearchForLastChar:
    	while (true) {
    	    while (i >= min && source[i] != strLastChar) {
    		i--;
    	    }
    	    if (i < min) {
    		return -1;
    	    }
    	    int j = i - 1;
    	    int start = j - (targetCount - 1);
    	    int k = strLastIndex - 1;
    
    	    while (j > start) {
    	        if (source[j--] != target[k--]) {
    		    i--;
    		    continue startSearchForLastChar;
    		}
    	    }
    	    return start - sourceOffset + 1;
    	}
        }
    
        /**
         * Returns a new string that is a substring of this string. The
         * substring begins with the character at the specified index and
         * extends to the end of this string. <p>
         * Examples:
         * <blockquote><pre>
         * "unhappy".substring(2) returns "happy"
         * "Harbison".substring(3) returns "bison"
         * "emptiness".substring(9) returns "" (an empty string)
         * </pre></blockquote>
         *
         * @param      beginIndex   the beginning index, inclusive.
         * @return     the specified substring.
         * @exception  IndexOutOfBoundsException  if
         *             <code>beginIndex</code> is negative or larger than the
         *             length of this <code>String</code> object.
         */
        public String substring(int beginIndex) {
    	return substring(beginIndex, count);
        }
    
        /**
         * Returns a new string that is a substring of this string. The
         * substring begins at the specified <code>beginIndex</code> and
         * extends to the character at index <code>endIndex - 1</code>.
         * Thus the length of the substring is <code>endIndex-beginIndex</code>.
         * <p>
         * Examples:
         * <blockquote><pre>
         * "hamburger".substring(4, 8) returns "urge"
         * "smiles".substring(1, 5) returns "mile"
         * </pre></blockquote>
         *
         * @param      beginIndex   the beginning index, inclusive.
         * @param      endIndex     the ending index, exclusive.
         * @return     the specified substring.
         * @exception  IndexOutOfBoundsException  if the
         *             <code>beginIndex</code> is negative, or
         *             <code>endIndex</code> is larger than the length of
         *             this <code>String</code> object, or
         *             <code>beginIndex</code> is larger than
         *             <code>endIndex</code>.
         */
        public String substring(int beginIndex, int endIndex) {
    	if (beginIndex < 0) {
    	    throw new StringIndexOutOfBoundsException(beginIndex);
    	}
    	if (endIndex > count) {
    	    throw new StringIndexOutOfBoundsException(endIndex);
    	}
    	if (beginIndex > endIndex) {
    	    throw new StringIndexOutOfBoundsException(endIndex - beginIndex);
    	}
    	return ((beginIndex == 0) && (endIndex == count)) ? this :
    	    new String(offset + beginIndex, endIndex - beginIndex, value);
        }
    
        /**
         * Returns a new character sequence that is a subsequence of this sequence.
         *
         * <p> An invocation of this method of the form
         *
         * <blockquote><pre>
         * str.subSequence(begin, end)</pre></blockquote>
         *
         * behaves in exactly the same way as the invocation
         *
         * <blockquote><pre>
         * str.substring(begin, end)</pre></blockquote>
         *
         * This method is defined so that the <tt>String</tt> class can implement
         * the {@link CharSequence} interface. </p>
         *
         * @param      beginIndex   the begin index, inclusive.
         * @param      endIndex     the end index, exclusive.
         * @return     the specified subsequence.
         *
         * @throws  IndexOutOfBoundsException
         *          if <tt>beginIndex</tt> or <tt>endIndex</tt> are negative,
         *          if <tt>endIndex</tt> is greater than <tt>length()</tt>,
         *          or if <tt>beginIndex</tt> is greater than <tt>startIndex</tt>
         *
         * @since 1.4
         * @spec JSR-51
         */
        public CharSequence subSequence(int beginIndex, int endIndex) {
            return this.substring(beginIndex, endIndex);
        }
    
        /**
         * Concatenates the specified string to the end of this string.
         * <p>
         * If the length of the argument string is <code>0</code>, then this
         * <code>String</code> object is returned. Otherwise, a new
         * <code>String</code> object is created, representing a character
         * sequence that is the concatenation of the character sequence
         * represented by this <code>String</code> object and the character
         * sequence represented by the argument string.<p>
         * Examples:
         * <blockquote><pre>
         * "cares".concat("s") returns "caress"
         * "to".concat("get").concat("her") returns "together"
         * </pre></blockquote>
         *
         * @param   str   the <code>String</code> that is concatenated to the end
         *                of this <code>String</code>.
         * @return  a string that represents the concatenation of this object's
         *          characters followed by the string argument's characters.
         */
        public String concat(String str) {
    	int otherLen = str.length();
    	if (otherLen == 0) {
    	    return this;
    	}
    	char buf[] = new char[count + otherLen];
    	getChars(0, count, buf, 0);
    	str.getChars(0, otherLen, buf, count);
    	return new String(0, count + otherLen, buf);
        }
    
        /**
         * Returns a new string resulting from replacing all occurrences of
         * <code>oldChar</code> in this string with <code>newChar</code>.
         * <p>
         * If the character <code>oldChar</code> does not occur in the
         * character sequence represented by this <code>String</code> object,
         * then a reference to this <code>String</code> object is returned.
         * Otherwise, a new <code>String</code> object is created that
         * represents a character sequence identical to the character sequence
         * represented by this <code>String</code> object, except that every
         * occurrence of <code>oldChar</code> is replaced by an occurrence
         * of <code>newChar</code>.
         * <p>
         * Examples:
         * <blockquote><pre>
         * "mesquite in your cellar".replace('e', 'o')
         *         returns "mosquito in your collar"
         * "the war of baronets".replace('r', 'y')
         *         returns "the way of bayonets"
         * "sparring with a purple porpoise".replace('p', 't')
         *         returns "starring with a turtle tortoise"
         * "JonL".replace('q', 'x') returns "JonL" (no change)
         * </pre></blockquote>
         *
         * @param   oldChar   the old character.
         * @param   newChar   the new character.
         * @return  a string derived from this string by replacing every
         *          occurrence of <code>oldChar</code> with <code>newChar</code>.
         */
        public String replace(char oldChar, char newChar) {
    	if (oldChar != newChar) {
    	    int len = count;
    	    int i = -1;
    	    char[] val = value; /* avoid getfield opcode */
    	    int off = offset;   /* avoid getfield opcode */
    
    	    while (++i < len) {
    		if (val[off + i] == oldChar) {
    		    break;
    		}
    	    }
    	    if (i < len) {
    		char buf[] = new char[len];
    		for (int j = 0 ; j < i ; j++) {
    		    buf[j] = val[off+j];
    		}
    		while (i < len) {
    		    char c = val[off + i];
    		    buf[i] = (c == oldChar) ? newChar : c;
    		    i++;
    		}
    		return new String(0, len, buf);
    	    }
    	}
    	return this;
        }
    
        /**
         * Tells whether or not this string matches the given <a
         * href="../util/regex/Pattern.html#sum">regular expression</a>.
         *
         * <p> An invocation of this method of the form
         * <i>str</i><tt>.matches(</tt><i>regex</i><tt>)</tt> yields exactly the
         * same result as the expression
         *
         * <blockquote><tt> {@link java.util.regex.Pattern}.{@link
         * java.util.regex.Pattern#matches(String,CharSequence)
         * matches}(</tt><i>regex</i><tt>,</tt> <i>str</i><tt>)</tt></blockquote>
         *
         * @param   regex
         *          the regular expression to which this string is to be matched
         *
         * @return  <tt>true</tt> if, and only if, this string matches the
         *          given regular expression
         *
         * @throws  PatternSyntaxException
         *          if the regular expression's syntax is invalid
         *
         * @see java.util.regex.Pattern
         *
         * @since 1.4
         * @spec JSR-51
         */
        public boolean matches(String regex) {
            return Pattern.matches(regex, this);
        }
    
        /**
         * Returns true if and only if this string contains the specified
         * sequence of char values.
         *
         * @param s the sequence to search for
         * @return true if this string contains <code>s</code>, false otherwise
         * @throws NullPointerException if <code>s</code> is <code>null</code>
         * @since 1.5
         */
        public boolean contains(CharSequence s) {
            return indexOf(s.toString()) > -1;
        }
    
        /**
         * Replaces the first substring of this string that matches the given <a
         * href="../util/regex/Pattern.html#sum">regular expression</a> with the
         * given replacement.
         *
         * <p> An invocation of this method of the form
         * <i>str</i><tt>.replaceFirst(</tt><i>regex</i><tt>,</tt> <i>repl</i><tt>)</tt>
         * yields exactly the same result as the expression
         *
         * <blockquote><tt>
         * {@link java.util.regex.Pattern}.{@link java.util.regex.Pattern#compile
         * compile}(</tt><i>regex</i><tt>).{@link
         * java.util.regex.Pattern#matcher(java.lang.CharSequence)
         * matcher}(</tt><i>str</i><tt>).{@link java.util.regex.Matcher#replaceFirst
         * replaceFirst}(</tt><i>repl</i><tt>)</tt></blockquote>
         *
         *<p>
         * Note that backslashes (<tt></tt>) and dollar signs (<tt>$</tt>) in the
         * replacement string may cause the results to be different than if it were
         * being treated as a literal replacement string; see
         * {@link java.util.regex.Matcher#replaceFirst}.
         * Use {@link java.util.regex.Matcher#quoteReplacement} to suppress the special
         * meaning of these characters, if desired.
         *
         * @param   regex
         *          the regular expression to which this string is to be matched
         * @param   replacement
         *          the string to be substituted for the first match
         *
         * @return  The resulting <tt>String</tt>
         *
         * @throws  PatternSyntaxException
         *          if the regular expression's syntax is invalid
         *
         * @see java.util.regex.Pattern
         *
         * @since 1.4
         * @spec JSR-51
         */
        public String replaceFirst(String regex, String replacement) {
    	return Pattern.compile(regex).matcher(this).replaceFirst(replacement);
        }
    
        /**
         * Replaces each substring of this string that matches the given <a
         * href="../util/regex/Pattern.html#sum">regular expression</a> with the
         * given replacement.
         *
         * <p> An invocation of this method of the form
         * <i>str</i><tt>.replaceAll(</tt><i>regex</i><tt>,</tt> <i>repl</i><tt>)</tt>
         * yields exactly the same result as the expression
         *
         * <blockquote><tt>
         * {@link java.util.regex.Pattern}.{@link java.util.regex.Pattern#compile
         * compile}(</tt><i>regex</i><tt>).{@link
         * java.util.regex.Pattern#matcher(java.lang.CharSequence)
         * matcher}(</tt><i>str</i><tt>).{@link java.util.regex.Matcher#replaceAll
         * replaceAll}(</tt><i>repl</i><tt>)</tt></blockquote>
         *
         *<p>
         * Note that backslashes (<tt></tt>) and dollar signs (<tt>$</tt>) in the
         * replacement string may cause the results to be different than if it were
         * being treated as a literal replacement string; see
         * {@link java.util.regex.Matcher#replaceAll Matcher.replaceAll}.
         * Use {@link java.util.regex.Matcher#quoteReplacement} to suppress the special
         * meaning of these characters, if desired.
         *
         * @param   regex
         *          the regular expression to which this string is to be matched
         * @param   replacement
         *          the string to be substituted for each match
         *
         * @return  The resulting <tt>String</tt>
         *
         * @throws  PatternSyntaxException
         *          if the regular expression's syntax is invalid
         *
         * @see java.util.regex.Pattern
         *
         * @since 1.4
         * @spec JSR-51
         */
        public String replaceAll(String regex, String replacement) {
    	return Pattern.compile(regex).matcher(this).replaceAll(replacement);
        }
    
        /**
         * Replaces each substring of this string that matches the literal target
         * sequence with the specified literal replacement sequence. The
         * replacement proceeds from the beginning of the string to the end, for
         * example, replacing "aa" with "b" in the string "aaa" will result in
         * "ba" rather than "ab".
         *
         * @param  target The sequence of char values to be replaced
         * @param  replacement The replacement sequence of char values
         * @return  The resulting string
         * @throws NullPointerException if <code>target</code> or
         *         <code>replacement</code> is <code>null</code>.
         * @since 1.5
         */
        public String replace(CharSequence target, CharSequence replacement) {
            return Pattern.compile(target.toString(), Pattern.LITERAL).matcher(
                this).replaceAll(Matcher.quoteReplacement(replacement.toString()));
        }
    
        /**
         * Splits this string around matches of the given
         * <a href="../util/regex/Pattern.html#sum">regular expression</a>.
         *
         * <p> The array returned by this method contains each substring of this
         * string that is terminated by another substring that matches the given
         * expression or is terminated by the end of the string.  The substrings in
         * the array are in the order in which they occur in this string.  If the
         * expression does not match any part of the input then the resulting array
         * has just one element, namely this string.
         *
         * <p> The <tt>limit</tt> parameter controls the number of times the
         * pattern is applied and therefore affects the length of the resulting
         * array.  If the limit <i>n</i> is greater than zero then the pattern
         * will be applied at most <i>n</i> - 1 times, the array's
         * length will be no greater than <i>n</i>, and the array's last entry
         * will contain all input beyond the last matched delimiter.  If <i>n</i>
         * is non-positive then the pattern will be applied as many times as
         * possible and the array can have any length.  If <i>n</i> is zero then
         * the pattern will be applied as many times as possible, the array can
         * have any length, and trailing empty strings will be discarded.
         *
         * <p> The string <tt>"boo:and:foo"</tt>, for example, yields the
         * following results with these parameters:
         *
         * <blockquote><table cellpadding=1 cellspacing=0 summary="Split example showing regex, limit, and result">
         * <tr>
         *     <th>Regex</th>
         *     <th>Limit</th>
         *     <th>Result</th>
         * </tr>
         * <tr><td align=center>:</td>
         *     <td align=center>2</td>
         *     <td><tt>{ "boo", "and:foo" }</tt></td></tr>
         * <tr><td align=center>:</td>
         *     <td align=center>5</td>
         *     <td><tt>{ "boo", "and", "foo" }</tt></td></tr>
         * <tr><td align=center>:</td>
         *     <td align=center>-2</td>
         *     <td><tt>{ "boo", "and", "foo" }</tt></td></tr>
         * <tr><td align=center>o</td>
         *     <td align=center>5</td>
         *     <td><tt>{ "b", "", ":and:f", "", "" }</tt></td></tr>
         * <tr><td align=center>o</td>
         *     <td align=center>-2</td>
         *     <td><tt>{ "b", "", ":and:f", "", "" }</tt></td></tr>
         * <tr><td align=center>o</td>
         *     <td align=center>0</td>
         *     <td><tt>{ "b", "", ":and:f" }</tt></td></tr>
         * </table></blockquote>
         *
         * <p> An invocation of this method of the form
         * <i>str.</i><tt>split(</tt><i>regex</i><tt>,</tt> <i>n</i><tt>)</tt>
         * yields the same result as the expression
         *
         * <blockquote>
         * {@link java.util.regex.Pattern}.{@link java.util.regex.Pattern#compile
         * compile}<tt>(</tt><i>regex</i><tt>)</tt>.{@link
         * java.util.regex.Pattern#split(java.lang.CharSequence,int)
         * split}<tt>(</tt><i>str</i><tt>,</tt> <i>n</i><tt>)</tt>
         * </blockquote>
         *
         *
         * @param  regex
         *         the delimiting regular expression
         *
         * @param  limit
         *         the result threshold, as described above
         *
         * @return  the array of strings computed by splitting this string
         *          around matches of the given regular expression
         *
         * @throws  PatternSyntaxException
         *          if the regular expression's syntax is invalid
         *
         * @see java.util.regex.Pattern
         *
         * @since 1.4
         * @spec JSR-51
         */
        public String[] split(String regex, int limit) {
    	return Pattern.compile(regex).split(this, limit);
        }
    
        /**
         * Splits this string around matches of the given <a
         * href="../util/regex/Pattern.html#sum">regular expression</a>.
         *
         * <p> This method works as if by invoking the two-argument {@link
         * #split(String, int) split} method with the given expression and a limit
         * argument of zero.  Trailing empty strings are therefore not included in
         * the resulting array.
         *
         * <p> The string <tt>"boo:and:foo"</tt>, for example, yields the following
         * results with these expressions:
         *
         * <blockquote><table cellpadding=1 cellspacing=0 summary="Split examples showing regex and result">
         * <tr>
         *  <th>Regex</th>
         *  <th>Result</th>
         * </tr>
         * <tr><td align=center>:</td>
         *     <td><tt>{ "boo", "and", "foo" }</tt></td></tr>
         * <tr><td align=center>o</td>
         *     <td><tt>{ "b", "", ":and:f" }</tt></td></tr>
         * </table></blockquote>
         *
         *
         * @param  regex
         *         the delimiting regular expression
         *
         * @return  the array of strings computed by splitting this string
         *          around matches of the given regular expression
         *
         * @throws  PatternSyntaxException
         *          if the regular expression's syntax is invalid
         *
         * @see java.util.regex.Pattern
         *
         * @since 1.4
         * @spec JSR-51
         */
        public String[] split(String regex) {
            return split(regex, 0);
        }
    
        /**
         * Converts all of the characters in this <code>String</code> to lower
         * case using the rules of the given <code>Locale</code>.  Case mapping is based
         * on the Unicode Standard version specified by the {@link java.lang.Character Character}
         * class. Since case mappings are not always 1:1 char mappings, the resulting
         * <code>String</code> may be a different length than the original <code>String</code>.
         * <p>
         * Examples of lowercase  mappings are in the following table:
         * <table border="1" summary="Lowercase mapping examples showing language code of locale, upper case, lower case, and description">
         * <tr>
         *   <th>Language Code of Locale</th>
         *   <th>Upper Case</th>
         *   <th>Lower Case</th>
         *   <th>Description</th>
         * </tr>
         * <tr>
         *   <td>tr (Turkish)</td>
         *   <td>u0130</td>
         *   <td>u0069</td>
         *   <td>capital letter I with dot above -> small letter i</td>
         * </tr>
         * <tr>
         *   <td>tr (Turkish)</td>
         *   <td>u0049</td>
         *   <td>u0131</td>
         *   <td>capital letter I -> small letter dotless i </td>
         * </tr>
         * <tr>
         *   <td>(all)</td>
         *   <td>French Fries</td>
         *   <td>french fries</td>
         *   <td>lowercased all chars in String</td>
         * </tr>
         * <tr>
         *   <td>(all)</td>
         *   <td><img src="doc-files/capiota.gif" alt="capiota"><img src="doc-files/capchi.gif" alt="capchi">
         *       <img src="doc-files/captheta.gif" alt="captheta"><img src="doc-files/capupsil.gif" alt="capupsil">
         *       <img src="doc-files/capsigma.gif" alt="capsigma"></td>
         *   <td><img src="doc-files/iota.gif" alt="iota"><img src="doc-files/chi.gif" alt="chi">
         *       <img src="doc-files/theta.gif" alt="theta"><img src="doc-files/upsilon.gif" alt="upsilon">
         *       <img src="doc-files/sigma1.gif" alt="sigma"></td>
         *   <td>lowercased all chars in String</td>
         * </tr>
         * </table>
         *
         * @param locale use the case transformation rules for this locale
         * @return the <code>String</code>, converted to lowercase.
         * @see     java.lang.String#toLowerCase()
         * @see     java.lang.String#toUpperCase()
         * @see     java.lang.String#toUpperCase(Locale)
         * @since   1.1
         */
        public String toLowerCase(Locale locale) {
    	if (locale == null) {
    	    throw new NullPointerException();
            }
    
            int     firstUpper;
    
    	/* Now check if there are any characters that need to be changed. */
    	scan: {
    	    for (firstUpper = 0 ; firstUpper < count; ) {
    		char c = value[offset+firstUpper];
    		if ((c >= Character.MIN_HIGH_SURROGATE) &&
    		    (c <= Character.MAX_HIGH_SURROGATE)) {
    		    int supplChar = codePointAt(firstUpper);
    		    if (supplChar != Character.toLowerCase(supplChar)) {
    		        break scan;
    		    }
    		    firstUpper += Character.charCount(supplChar);
    		} else {
    		    if (c != Character.toLowerCase(c)) {
    		        break scan;
    		    }
    		    firstUpper++;
    		}
    	    }
    	    return this;
    	}
    
            char[]  result = new char[count];
    	int     resultOffset = 0;  /* result may grow, so i+resultOffset
    				    * is the write location in result */
    
            /* Just copy the first few lowerCase characters. */
            System.arraycopy(value, offset, result, 0, firstUpper);
    
    	String lang = locale.getLanguage();
    	boolean localeDependent =
                (lang == "tr" || lang == "az" || lang == "lt");
            char[] lowerCharArray;
            int lowerChar;
            int srcChar;
            int srcCount;
            for (int i = firstUpper; i < count; i += srcCount) {
    	    srcChar = (int)value[offset+i];
    	    if ((char)srcChar >= Character.MIN_HIGH_SURROGATE &&
    	        (char)srcChar <= Character.MAX_HIGH_SURROGATE) {
    		srcChar = codePointAt(i);
    		srcCount = Character.charCount(srcChar);
    	    } else {
    	        srcCount = 1;
    	    }
                if (localeDependent || srcChar == 'u03A3') { // GREEK CAPITAL LETTER SIGMA
                    lowerChar = ConditionalSpecialCasing.toLowerCaseEx(this, i, locale);
                } else {
                    lowerChar = Character.toLowerCase(srcChar);
                }
                if ((lowerChar == Character.ERROR) ||
                    (lowerChar >= Character.MIN_SUPPLEMENTARY_CODE_POINT)) {
                    if (lowerChar == Character.ERROR) {
                        lowerCharArray =
                            ConditionalSpecialCasing.toLowerCaseCharArray(this, i, locale);
                    } else if (srcCount == 2) {
    		    resultOffset += Character.toChars(lowerChar, result, i + resultOffset) - srcCount;
    		    continue;
                    } else {
    		    lowerCharArray = Character.toChars(lowerChar);
    		}
    
                    /* Grow result if needed */
                    int mapLen = lowerCharArray.length;
    		if (mapLen > srcCount) {
                        char[] result2 = new char[result.length + mapLen - srcCount];
                        System.arraycopy(result, 0, result2, 0,
                            i + resultOffset);
                        result = result2;
    		}
                    for (int x=0; x<mapLen; ++x) {
                        result[i+resultOffset+x] = lowerCharArray[x];
                    }
                    resultOffset += (mapLen - srcCount);
                } else {
                    result[i+resultOffset] = (char)lowerChar;
                }
            }
            return new String(0, count+resultOffset, result);
        }
    
        /**
         * Converts all of the characters in this <code>String</code> to lower
         * case using the rules of the default locale. This is equivalent to calling
         * <code>toLowerCase(Locale.getDefault())</code>.
         * <p>
         * <b>Note:</b> This method is locale sensitive, and may produce unexpected
         * results if used for strings that are intended to be interpreted locale
         * independently.
         * Examples are programming language identifiers, protocol keys, and HTML
         * tags.
         * For instance, <code>"TITLE".toLowerCase()</code> in a Turkish locale
         * returns <code>"tu0131tle"</code>, where 'u0131' is the LATIN SMALL
         * LETTER DOTLESS I character.
         * To obtain correct results for locale insensitive strings, use
         * <code>toLowerCase(Locale.ENGLISH)</code>.
         * <p>
         * @return  the <code>String</code>, converted to lowercase.
         * @see     java.lang.String#toLowerCase(Locale)
         */
        public String toLowerCase() {
            return toLowerCase(Locale.getDefault());
        }
    
        /**
         * Converts all of the characters in this <code>String</code> to upper
         * case using the rules of the given <code>Locale</code>. Case mapping is based
         * on the Unicode Standard version specified by the {@link java.lang.Character Character}
         * class. Since case mappings are not always 1:1 char mappings, the resulting
         * <code>String</code> may be a different length than the original <code>String</code>.
         * <p>
         * Examples of locale-sensitive and 1:M case mappings are in the following table.
         * <p>
         * <table border="1" summary="Examples of locale-sensitive and 1:M case mappings. Shows Language code of locale, lower case, upper case, and description.">
         * <tr>
         *   <th>Language Code of Locale</th>
         *   <th>Lower Case</th>
         *   <th>Upper Case</th>
         *   <th>Description</th>
         * </tr>
         * <tr>
         *   <td>tr (Turkish)</td>
         *   <td>u0069</td>
         *   <td>u0130</td>
         *   <td>small letter i -> capital letter I with dot above</td>
         * </tr>
         * <tr>
         *   <td>tr (Turkish)</td>
         *   <td>u0131</td>
         *   <td>u0049</td>
         *   <td>small letter dotless i -> capital letter I</td>
         * </tr>
         * <tr>
         *   <td>(all)</td>
         *   <td>u00df</td>
         *   <td>u0053 u0053</td>
         *   <td>small letter sharp s -> two letters: SS</td>
         * </tr>
         * <tr>
         *   <td>(all)</td>
         *   <td>Fahrvergnügen</td>
         *   <td>FAHRVERGNÜGEN</td>
         *   <td></td>
         * </tr>
         * </table>
         * @param locale use the case transformation rules for this locale
         * @return the <code>String</code>, converted to uppercase.
         * @see     java.lang.String#toUpperCase()
         * @see     java.lang.String#toLowerCase()
         * @see     java.lang.String#toLowerCase(Locale)
         * @since   1.1
         */
        public String toUpperCase(Locale locale) {
    	if (locale == null) {
    	    throw new NullPointerException();
            }
    
            int     firstLower;
    
    	/* Now check if there are any characters that need to be changed. */
    	scan: {
    	    for (firstLower = 0 ; firstLower < count; ) {
    		int c = (int)value[offset+firstLower];
    		int srcCount;
    		if ((c >= Character.MIN_HIGH_SURROGATE) &&
    		    (c <= Character.MAX_HIGH_SURROGATE)) {
    		    c = codePointAt(firstLower);
    		    srcCount = Character.charCount(c);
    		} else {
    		    srcCount = 1;
    		}
    		int upperCaseChar = Character.toUpperCaseEx(c);
    		if ((upperCaseChar == Character.ERROR) ||
    		    (c != upperCaseChar)) {
    		    break scan;
    		}
    		firstLower += srcCount;
    	    }
    	    return this;
    	}
    
            char[]  result       = new char[count]; /* may grow */
    	int     resultOffset = 0;  /* result may grow, so i+resultOffset
    				    * is the write location in result */
    
    	/* Just copy the first few upperCase characters. */
    	System.arraycopy(value, offset, result, 0, firstLower);
    
    	String lang = locale.getLanguage();
    	boolean localeDependent =
                (lang == "tr" || lang == "az" || lang == "lt");
            char[] upperCharArray;
            int upperChar;
            int srcChar;
            int srcCount;
            for (int i = firstLower; i < count; i += srcCount) {
    	    srcChar = (int)value[offset+i];
    	    if ((char)srcChar >= Character.MIN_HIGH_SURROGATE &&
    	        (char)srcChar <= Character.MAX_HIGH_SURROGATE) {
    		srcChar = codePointAt(i);
    		srcCount = Character.charCount(srcChar);
    	    } else {
    	        srcCount = 1;
    	    }
                if (localeDependent) {
                    upperChar = ConditionalSpecialCasing.toUpperCaseEx(this, i, locale);
                } else {
                    upperChar = Character.toUpperCaseEx(srcChar);
                }
                if ((upperChar == Character.ERROR) ||
                    (upperChar >= Character.MIN_SUPPLEMENTARY_CODE_POINT)) {
                    if (upperChar == Character.ERROR) {
                        if (localeDependent) {
                            upperCharArray =
                                ConditionalSpecialCasing.toUpperCaseCharArray(this, i, locale);
                        } else {
                            upperCharArray = Character.toUpperCaseCharArray(srcChar);
                        }
                    } else if (srcCount == 2) {
    		    resultOffset += Character.toChars(upperChar, result, i + resultOffset) - srcCount;
    		    continue;
                    } else {
                        upperCharArray = Character.toChars(upperChar);
    		}
    
                    /* Grow result if needed */
                    int mapLen = upperCharArray.length;
    		if (mapLen > srcCount) {
                        char[] result2 = new char[result.length + mapLen - srcCount];
                        System.arraycopy(result, 0, result2, 0,
                            i + resultOffset);
                        result = result2;
    		}
                    for (int x=0; x<mapLen; ++x) {
                        result[i+resultOffset+x] = upperCharArray[x];
                    }
                    resultOffset += (mapLen - srcCount);
                } else {
                    result[i+resultOffset] = (char)upperChar;
                }
            }
            return new String(0, count+resultOffset, result);
        }
    
        /**
         * Converts all of the characters in this <code>String</code> to upper
         * case using the rules of the default locale. This method is equivalent to
         * <code>toUpperCase(Locale.getDefault())</code>.
         * <p>
         * <b>Note:</b> This method is locale sensitive, and may produce unexpected
         * results if used for strings that are intended to be interpreted locale
         * independently.
         * Examples are programming language identifiers, protocol keys, and HTML
         * tags.
         * For instance, <code>"title".toUpperCase()</code> in a Turkish locale
         * returns <code>"Tu0130TLE"</code>, where 'u0130' is the LATIN CAPITAL
         * LETTER I WITH DOT ABOVE character.
         * To obtain correct results for locale insensitive strings, use
         * <code>toUpperCase(Locale.ENGLISH)</code>.
         * <p>
         * @return  the <code>String</code>, converted to uppercase.
         * @see     java.lang.String#toUpperCase(Locale)
         */
        public String toUpperCase() {
            return toUpperCase(Locale.getDefault());
        }
    
        /**
         * Returns a copy of the string, with leading and trailing whitespace
         * omitted.
         * <p>
         * If this <code>String</code> object represents an empty character
         * sequence, or the first and last characters of character sequence
         * represented by this <code>String</code> object both have codes
         * greater than <code>'u0020'</code> (the space character), then a
         * reference to this <code>String</code> object is returned.
         * <p>
         * Otherwise, if there is no character with a code greater than
         * <code>'u0020'</code> in the string, then a new
         * <code>String</code> object representing an empty string is created
         * and returned.
         * <p>
         * Otherwise, let <i>k</i> be the index of the first character in the
         * string whose code is greater than <code>'u0020'</code>, and let
         * <i>m</i> be the index of the last character in the string whose code
         * is greater than <code>'u0020'</code>. A new <code>String</code>
         * object is created, representing the substring of this string that
         * begins with the character at index <i>k</i> and ends with the
         * character at index <i>m</i>-that is, the result of
         * <code>this.substring(<i>k</i>, <i>m</i>+1)</code>.
         * <p>
         * This method may be used to trim whitespace (as defined above) from
         * the beginning and end of a string.
         *
         * @return  A copy of this string with leading and trailing white
         *          space removed, or this string if it has no leading or
         *          trailing white space.
         */
        public String trim() {
    	int len = count;
    	int st = 0;
    	int off = offset;      /* avoid getfield opcode */
    	char[] val = value;    /* avoid getfield opcode */
    
    	while ((st < len) && (val[off + st] <= ' ')) {
    	    st++;
    	}
    	while ((st < len) && (val[off + len - 1] <= ' ')) {
    	    len--;
    	}
    	return ((st > 0) || (len < count)) ? substring(st, len) : this;
        }
    
        /**
         * This object (which is already a string!) is itself returned.
         *
         * @return  the string itself.
         */
        public String toString() {
    	return this;
        }
    
        /**
         * Converts this string to a new character array.
         *
         * @return  a newly allocated character array whose length is the length
         *          of this string and whose contents are initialized to contain
         *          the character sequence represented by this string.
         */
        public char[] toCharArray() {
    	char result[] = new char[count];
    	getChars(0, count, result, 0);
    	return result;
        }
    
        /**
         * Returns a formatted string using the specified format string and
         * arguments.
         *
         * <p> The locale always used is the one returned by {@link
         * java.util.Locale#getDefault() Locale.getDefault()}.
         *
         * @param  format
         *         A <a href="../util/Formatter.html#syntax">format string</a>
         *
         * @param  args
         *         Arguments referenced by the format specifiers in the format
         *         string.  If there are more arguments than format specifiers, the
         *         extra arguments are ignored.  The number of arguments is
         *         variable and may be zero.  The maximum number of arguments is
         *         limited by the maximum dimension of a Java array as defined by
         *         the <a href="http://java.sun.com/docs/books/vmspec/">Java
         *         Virtual Machine Specification</a>.  The behaviour on a
         *         <tt>null</tt> argument depends on the <a
         *         href="../util/Formatter.html#syntax">conversion</a>.
         *
         * @throws  IllegalFormatException
         *          If a format string contains an illegal syntax, a format
         *          specifier that is incompatible with the given arguments,
         *          insufficient arguments given the format string, or other
         *          illegal conditions.  For specification of all possible
         *          formatting errors, see the <a
         *          href="../util/Formatter.html#detail">Details</a> section of the
         *          formatter class specification.
         *
         * @throws  NullPointerException
         *          If the <tt>format</tt> is <tt>null</tt>
         *
         * @return  A formatted string
         *
         * @see  java.util.Formatter
         * @since  1.5
         */
        public static String format(String format, Object ... args) {
    	return new Formatter().format(format, args).toString();
        }
    
        /**
         * Returns a formatted string using the specified locale, format string,
         * and arguments.
         *
         * @param  l
         *         The {@linkplain java.util.Locale locale} to apply during
         *         formatting.  If <tt>l</tt> is <tt>null</tt> then no localization
         *         is applied.
         *
         * @param  format
         *         A <a href="../util/Formatter.html#syntax">format string</a>
         *
         * @param  args
         *         Arguments referenced by the format specifiers in the format
         *         string.  If there are more arguments than format specifiers, the
         *         extra arguments are ignored.  The number of arguments is
         *         variable and may be zero.  The maximum number of arguments is
         *         limited by the maximum dimension of a Java array as defined by
         *         the <a href="http://java.sun.com/docs/books/vmspec/">Java
         *         Virtual Machine Specification</a>.  The behaviour on a
         *         <tt>null</tt> argument depends on the <a
         *         href="../util/Formatter.html#syntax">conversion</a>.
         *
         * @throws  IllegalFormatException
         *          If a format string contains an illegal syntax, a format
         *          specifier that is incompatible with the given arguments,
         *          insufficient arguments given the format string, or other
         *          illegal conditions.  For specification of all possible
         *          formatting errors, see the <a
         *          href="../util/Formatter.html#detail">Details</a> section of the
         *          formatter class specification
         *
         * @throws  NullPointerException
         *          If the <tt>format</tt> is <tt>null</tt>
         *
         * @return  A formatted string
         *
         * @see  java.util.Formatter
         * @since  1.5
         */
        public static String format(Locale l, String format, Object ... args) {
    	return new Formatter(l).format(format, args).toString();
        }
    
        /**
         * Returns the string representation of the <code>Object</code> argument.
         *
         * @param   obj   an <code>Object</code>.
         * @return  if the argument is <code>null</code>, then a string equal to
         *          <code>"null"</code>; otherwise, the value of
         *          <code>obj.toString()</code> is returned.
         * @see     java.lang.Object#toString()
         */
        public static String valueOf(Object obj) {
    	return (obj == null) ? "null" : obj.toString();
        }
    
        /**
         * Returns the string representation of the <code>char</code> array
         * argument. The contents of the character array are copied; subsequent
         * modification of the character array does not affect the newly
         * created string.
         *
         * @param   data   a <code>char</code> array.
         * @return  a newly allocated string representing the same sequence of
         *          characters contained in the character array argument.
         */
        public static String valueOf(char data[]) {
    	return new String(data);
        }
    
        /**
         * Returns the string representation of a specific subarray of the
         * <code>char</code> array argument.
         * <p>
         * The <code>offset</code> argument is the index of the first
         * character of the subarray. The <code>count</code> argument
         * specifies the length of the subarray. The contents of the subarray
         * are copied; subsequent modification of the character array does not
         * affect the newly created string.
         *
         * @param   data     the character array.
         * @param   offset   the initial offset into the value of the
         *                  <code>String</code>.
         * @param   count    the length of the value of the <code>String</code>.
         * @return  a string representing the sequence of characters contained
         *          in the subarray of the character array argument.
         * @exception IndexOutOfBoundsException if <code>offset</code> is
         *          negative, or <code>count</code> is negative, or
         *          <code>offset+count</code> is larger than
         *          <code>data.length</code>.
         */
        public static String valueOf(char data[], int offset, int count) {
    	return new String(data, offset, count);
        }
    
        /**
         * Returns a String that represents the character sequence in the
         * array specified.
         *
         * @param   data     the character array.
         * @param   offset   initial offset of the subarray.
         * @param   count    length of the subarray.
         * @return  a <code>String</code> that contains the characters of the
         *          specified subarray of the character array.
         */
        public static String copyValueOf(char data[], int offset, int count) {
    	// All public String constructors now copy the data.
    	return new String(data, offset, count);
        }
    
        /**
         * Returns a String that represents the character sequence in the
         * array specified.
         *
         * @param   data   the character array.
         * @return  a <code>String</code> that contains the characters of the
         *          character array.
         */
        public static String copyValueOf(char data[]) {
    	return copyValueOf(data, 0, data.length);
        }
    
        /**
         * Returns the string representation of the <code>boolean</code> argument.
         *
         * @param   b   a <code>boolean</code>.
         * @return  if the argument is <code>true</code>, a string equal to
         *          <code>"true"</code> is returned; otherwise, a string equal to
         *          <code>"false"</code> is returned.
         */
        public static String valueOf(boolean b) {
    	return b ? "true" : "false";
        }
    
        /**
         * Returns the string representation of the <code>char</code>
         * argument.
         *
         * @param   c   a <code>char</code>.
         * @return  a string of length <code>1</code> containing
         *          as its single character the argument <code>c</code>.
         */
        public static String valueOf(char c) {
    	char data[] = {c};
    	return new String(0, 1, data);
        }
    
        /**
         * Returns the string representation of the <code>int</code> argument.
         * <p>
         * The representation is exactly the one returned by the
         * <code>Integer.toString</code> method of one argument.
         *
         * @param   i   an <code>int</code>.
         * @return  a string representation of the <code>int</code> argument.
         * @see     java.lang.Integer#toString(int, int)
         */
        public static String valueOf(int i) {
            return Integer.toString(i, 10);
        }
    
        /**
         * Returns the string representation of the <code>long</code> argument.
         * <p>
         * The representation is exactly the one returned by the
         * <code>Long.toString</code> method of one argument.
         *
         * @param   l   a <code>long</code>.
         * @return  a string representation of the <code>long</code> argument.
         * @see     java.lang.Long#toString(long)
         */
        public static String valueOf(long l) {
            return Long.toString(l, 10);
        }
    
        /**
         * Returns the string representation of the <code>float</code> argument.
         * <p>
         * The representation is exactly the one returned by the
         * <code>Float.toString</code> method of one argument.
         *
         * @param   f   a <code>float</code>.
         * @return  a string representation of the <code>float</code> argument.
         * @see     java.lang.Float#toString(float)
         */
        public static String valueOf(float f) {
    	return Float.toString(f);
        }
    
        /**
         * Returns the string representation of the <code>double</code> argument.
         * <p>
         * The representation is exactly the one returned by the
         * <code>Double.toString</code> method of one argument.
         *
         * @param   d   a <code>double</code>.
         * @return  a  string representation of the <code>double</code> argument.
         * @see     java.lang.Double#toString(double)
         */
        public static String valueOf(double d) {
    	return Double.toString(d);
        }
    
        /**
         * Returns a canonical representation for the string object.
         * <p>
         * A pool of strings, initially empty, is maintained privately by the
         * class <code>String</code>.
         * <p>
         * When the intern method is invoked, if the pool already contains a
         * string equal to this <code>String</code> object as determined by
         * the {@link #equals(Object)} method, then the string from the pool is
         * returned. Otherwise, this <code>String</code> object is added to the
         * pool and a reference to this <code>String</code> object is returned.
         * <p>
         * It follows that for any two strings <code>s</code> and <code>t</code>,
         * <code>s.intern() == t.intern()</code> is <code>true</code>
         * if and only if <code>s.equals(t)</code> is <code>true</code>.
         * <p>
         * All literal strings and string-valued constant expressions are
         * interned. String literals are defined in §3.10.5 of the
         * <a href="http://java.sun.com/docs/books/jls/html/">Java Language
         * Specification</a>
         *
         * @return  a string that has the same contents as this string, but is
         *          guaranteed to be from a pool of unique strings.
         */
        public native String intern();
    
    }
    
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  • 原文地址:https://www.cnblogs.com/heiniao/p/5807650.html
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