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  • Elements

    Elements

    package org.jsoup.select;
    
    import org.jsoup.helper.Validate;
    import org.jsoup.nodes.Element;
    import org.jsoup.nodes.FormElement;
    import org.jsoup.nodes.Node;
    
    import java.util.ArrayList;
    import java.util.Arrays;
    import java.util.Collection;
    import java.util.HashSet;
    import java.util.LinkedHashSet;
    import java.util.List;
    
    /**
     A list of {@link Element}s, with methods that act on every element in the list.
     <p>
     To get an {@code Elements} object, use the {@link Element#select(String)} method.
     </p>
    
     @author Jonathan Hedley, jonathan@hedley.net */
    public class Elements extends ArrayList<Element> {
        public Elements() {
        }
    
        public Elements(int initialCapacity) {
            super(initialCapacity);
        }
    
        public Elements(Collection<Element> elements) {
            super(elements);
        }
        
        public Elements(List<Element> elements) {
            super(elements);
        }
        
        public Elements(Element... elements) {
            super(Arrays.asList(elements));
        }
    
        /**
         * Creates a deep copy of these elements.
         * @return a deep copy
         */
        @Override
        public Elements clone() {
            Elements clone = new Elements(size());
    
            for(Element e : this)
                clone.add(e.clone());
            
            return clone;
        }
    
        // attribute methods
        /**
         Get an attribute value from the first matched element that has the attribute.
         @param attributeKey The attribute key.
         @return The attribute value from the first matched element that has the attribute.. If no elements were matched (isEmpty() == true),
         or if the no elements have the attribute, returns empty string.
         @see #hasAttr(String)
         */
        public String attr(String attributeKey) {
            for (Element element : this) {
                if (element.hasAttr(attributeKey))
                    return element.attr(attributeKey);
            }
            return "";
        }
    
        /**
         Checks if any of the matched elements have this attribute defined.
         @param attributeKey attribute key
         @return true if any of the elements have the attribute; false if none do.
         */
        public boolean hasAttr(String attributeKey) {
            for (Element element : this) {
                if (element.hasAttr(attributeKey))
                    return true;
            }
            return false;
        }
    
        /**
         * Get the attribute value for each of the matched elements. If an element does not have this attribute, no value is
         * included in the result set for that element.
         * @param attributeKey the attribute name to return values for. You can add the {@code abs:} prefix to the key to
         * get absolute URLs from relative URLs, e.g.: {@code doc.select("a").eachAttr("abs:href")} .
         * @return a list of each element's attribute value for the attribute
         */
        public List<String> eachAttr(String attributeKey) {
            List<String> attrs = new ArrayList<>(size());
            for (Element element : this) {
                if (element.hasAttr(attributeKey))
                    attrs.add(element.attr(attributeKey));
            }
            return attrs;
        }
    
        /**
         * Set an attribute on all matched elements.
         * @param attributeKey attribute key
         * @param attributeValue attribute value
         * @return this
         */
        public Elements attr(String attributeKey, String attributeValue) {
            for (Element element : this) {
                element.attr(attributeKey, attributeValue);
            }
            return this;
        }
    
        /**
         * Remove an attribute from every matched element.
         * @param attributeKey The attribute to remove.
         * @return this (for chaining)
         */
        public Elements removeAttr(String attributeKey) {
            for (Element element : this) {
                element.removeAttr(attributeKey);
            }
            return this;
        }
    
        /**
         Add the class name to every matched element's {@code class} attribute.
         @param className class name to add
         @return this
         */
        public Elements addClass(String className) {
            for (Element element : this) {
                element.addClass(className);
            }
            return this;
        }
    
        /**
         Remove the class name from every matched element's {@code class} attribute, if present.
         @param className class name to remove
         @return this
         */
        public Elements removeClass(String className) {
            for (Element element : this) {
                element.removeClass(className);
            }
            return this;
        }
    
        /**
         Toggle the class name on every matched element's {@code class} attribute.
         @param className class name to add if missing, or remove if present, from every element.
         @return this
         */
        public Elements toggleClass(String className) {
            for (Element element : this) {
                element.toggleClass(className);
            }
            return this;
        }
    
        /**
         Determine if any of the matched elements have this class name set in their {@code class} attribute.
         @param className class name to check for
         @return true if any do, false if none do
         */
        public boolean hasClass(String className) {
            for (Element element : this) {
                if (element.hasClass(className))
                    return true;
            }
            return false;
        }
        
        /**
         * Get the form element's value of the first matched element.
         * @return The form element's value, or empty if not set.
         * @see Element#val()
         */
        public String val() {
            if (size() > 0)
                return first().val();
            else
                return "";
        }
        
        /**
         * Set the form element's value in each of the matched elements.
         * @param value The value to set into each matched element
         * @return this (for chaining)
         */
        public Elements val(String value) {
            for (Element element : this)
                element.val(value);
            return this;
        }
        
        /**
         * Get the combined text of all the matched elements.
         * <p>
         * Note that it is possible to get repeats if the matched elements contain both parent elements and their own
         * children, as the Element.text() method returns the combined text of a parent and all its children.
         * @return string of all text: unescaped and no HTML.
         * @see Element#text()
         * @see #eachText()
         */
        public String text() {
            StringBuilder sb = new StringBuilder();
            for (Element element : this) {
                if (sb.length() != 0)
                    sb.append(" ");
                sb.append(element.text());
            }
            return sb.toString();
        }
    
        /**
         Test if any matched Element has any text content, that is not just whitespace.
         @return true if any element has non-blank text content.
         @see Element#hasText()
         */
        public boolean hasText() {
            for (Element element: this) {
                if (element.hasText())
                    return true;
            }
            return false;
        }
    
        /**
         * Get the text content of each of the matched elements. If an element has no text, then it is not included in the
         * result.
         * @return A list of each matched element's text content.
         * @see Element#text()
         * @see Element#hasText()
         * @see #text()
         */
        public List<String> eachText() {
            ArrayList<String> texts = new ArrayList<>(size());
            for (Element el: this) {
                if (el.hasText())
                    texts.add(el.text());
            }
            return texts;
        }
        
        /**
         * Get the combined inner HTML of all matched elements.
         * @return string of all element's inner HTML.
         * @see #text()
         * @see #outerHtml()
         */
        public String html() {
            StringBuilder sb = new StringBuilder();
            for (Element element : this) {
                if (sb.length() != 0)
                    sb.append("
    ");
                sb.append(element.html());
            }
            return sb.toString();
        }
        
        /**
         * Get the combined outer HTML of all matched elements.
         * @return string of all element's outer HTML.
         * @see #text()
         * @see #html()
         */
        public String outerHtml() {
            StringBuilder sb = new StringBuilder();
            for (Element element : this) {
                if (sb.length() != 0)
                    sb.append("
    ");
                sb.append(element.outerHtml());
            }
            return sb.toString();
        }
    
        /**
         * Get the combined outer HTML of all matched elements. Alias of {@link #outerHtml()}.
         * @return string of all element's outer HTML.
         * @see #text()
         * @see #html()
         */
        @Override
        public String toString() {
            return outerHtml();
        }
    
        /**
         * Update the tag name of each matched element. For example, to change each {@code <i>} to a {@code <em>}, do
         * {@code doc.select("i").tagName("em");}
         * @param tagName the new tag name
         * @return this, for chaining
         * @see Element#tagName(String)
         */
        public Elements tagName(String tagName) {
            for (Element element : this) {
                element.tagName(tagName);
            }
            return this;
        }
        
        /**
         * Set the inner HTML of each matched element.
         * @param html HTML to parse and set into each matched element.
         * @return this, for chaining
         * @see Element#html(String)
         */
        public Elements html(String html) {
            for (Element element : this) {
                element.html(html);
            }
            return this;
        }
        
        /**
         * Add the supplied HTML to the start of each matched element's inner HTML.
         * @param html HTML to add inside each element, before the existing HTML
         * @return this, for chaining
         * @see Element#prepend(String)
         */
        public Elements prepend(String html) {
            for (Element element : this) {
                element.prepend(html);
            }
            return this;
        }
        
        /**
         * Add the supplied HTML to the end of each matched element's inner HTML.
         * @param html HTML to add inside each element, after the existing HTML
         * @return this, for chaining
         * @see Element#append(String)
         */
        public Elements append(String html) {
            for (Element element : this) {
                element.append(html);
            }
            return this;
        }
        
        /**
         * Insert the supplied HTML before each matched element's outer HTML.
         * @param html HTML to insert before each element
         * @return this, for chaining
         * @see Element#before(String)
         */
        public Elements before(String html) {
            for (Element element : this) {
                element.before(html);
            }
            return this;
        }
        
        /**
         * Insert the supplied HTML after each matched element's outer HTML.
         * @param html HTML to insert after each element
         * @return this, for chaining
         * @see Element#after(String)
         */
        public Elements after(String html) {
            for (Element element : this) {
                element.after(html);
            }
            return this;
        }
    
        /**
         Wrap the supplied HTML around each matched elements. For example, with HTML
         {@code <p><b>This</b> is <b>Jsoup</b></p>},
         <code>doc.select("b").wrap("&lt;i&gt;&lt;/i&gt;");</code>
         becomes {@code <p><i><b>This</b></i> is <i><b>jsoup</b></i></p>}
         @param html HTML to wrap around each element, e.g. {@code <div class="head"></div>}. Can be arbitrarily deep.
         @return this (for chaining)
         @see Element#wrap
         */
        public Elements wrap(String html) {
            Validate.notEmpty(html);
            for (Element element : this) {
                element.wrap(html);
            }
            return this;
        }
    
        /**
         * Removes the matched elements from the DOM, and moves their children up into their parents. This has the effect of
         * dropping the elements but keeping their children.
         * <p>
         * This is useful for e.g removing unwanted formatting elements but keeping their contents.
         * </p>
         * 
         * E.g. with HTML: <p>{@code <div><font>One</font> <font><a href="/">Two</a></font></div>}</p>
         * <p>{@code doc.select("font").unwrap();}</p>
         * <p>HTML = {@code <div>One <a href="/">Two</a></div>}</p>
         *
         * @return this (for chaining)
         * @see Node#unwrap
         */
        public Elements unwrap() {
            for (Element element : this) {
                element.unwrap();
            }
            return this;
        }
    
        /**
         * Empty (remove all child nodes from) each matched element. This is similar to setting the inner HTML of each
         * element to nothing.
         * <p>
         * E.g. HTML: {@code <div><p>Hello <b>there</b></p> <p>now</p></div>}<br>
         * <code>doc.select("p").empty();</code><br>
         * HTML = {@code <div><p></p> <p></p></div>}
         * @return this, for chaining
         * @see Element#empty()
         * @see #remove()
         */
        public Elements empty() {
            for (Element element : this) {
                element.empty();
            }
            return this;
        }
    
        /**
         * Remove each matched element from the DOM. This is similar to setting the outer HTML of each element to nothing.
         * <p>
         * E.g. HTML: {@code <div><p>Hello</p> <p>there</p> <img /></div>}<br>
         * <code>doc.select("p").remove();</code><br>
         * HTML = {@code <div> <img /></div>}
         * <p>
         * Note that this method should not be used to clean user-submitted HTML; rather, use {@link org.jsoup.safety.Cleaner} to clean HTML.
         * @return this, for chaining
         * @see Element#empty()
         * @see #empty()
         */
        public Elements remove() {
            for (Element element : this) {
                element.remove();
            }
            return this;
        }
        
        // filters
        
        /**
         * Find matching elements within this element list.
         * @param query A {@link Selector} query
         * @return the filtered list of elements, or an empty list if none match.
         */
        public Elements select(String query) {
            return Selector.select(query, this);
        }
    
        /**
         * Remove elements from this list that match the {@link Selector} query.
         * <p>
         * E.g. HTML: {@code <div class=logo>One</div> <div>Two</div>}<br>
         * <code>Elements divs = doc.select("div").not(".logo");</code><br>
         * Result: {@code divs: [<div>Two</div>]}
         * <p>
         * @param query the selector query whose results should be removed from these elements
         * @return a new elements list that contains only the filtered results
         */
        public Elements not(String query) {
            Elements out = Selector.select(query, this);
            return Selector.filterOut(this, out);
        }
        
        /**
         * Get the <i>nth</i> matched element as an Elements object.
         * <p>
         * See also {@link #get(int)} to retrieve an Element.
         * @param index the (zero-based) index of the element in the list to retain
         * @return Elements containing only the specified element, or, if that element did not exist, an empty list.
         */
        public Elements eq(int index) {
            return size() > index ? new Elements(get(index)) : new Elements();
        }
        
        /**
         * Test if any of the matched elements match the supplied query.
         * @param query A selector
         * @return true if at least one element in the list matches the query.
         */
        public boolean is(String query) {
            Evaluator eval = QueryParser.parse(query);
            for (Element e : this) {
                if (e.is(eval))
                    return true;
            }
            return false;
        }
    
        /**
         * Get the immediate next element sibling of each element in this list.
         * @return next element siblings.
         */
        public Elements next() {
            return siblings(null, true, false);
        }
    
        /**
         * Get the immediate next element sibling of each element in this list, filtered by the query.
         * @param query CSS query to match siblings against
         * @return next element siblings.
         */
        public Elements next(String query) {
            return siblings(query, true, false);
        }
    
        /**
         * Get all of the following element siblings of each element in this list.
         * @return all following element siblings.
         */
        public Elements nextAll() {
            return siblings(null, true, true);
        }
    
        /**
         * Get all of the following element siblings of each element in this list, filtered by the query.
         * @param query CSS query to match siblings against
         * @return all following element siblings.
         */
        public Elements nextAll(String query) {
            return siblings(query, true, true);
        }
    
        /**
         * Get the immediate previous element sibling of each element in this list.
         * @return previous element siblings.
         */
        public Elements prev() {
            return siblings(null, false, false);
        }
    
        /**
         * Get the immediate previous element sibling of each element in this list, filtered by the query.
         * @param query CSS query to match siblings against
         * @return previous element siblings.
         */
        public Elements prev(String query) {
            return siblings(query, false, false);
        }
    
        /**
         * Get all of the previous element siblings of each element in this list.
         * @return all previous element siblings.
         */
        public Elements prevAll() {
            return siblings(null, false, true);
        }
    
        /**
         * Get all of the previous element siblings of each element in this list, filtered by the query.
         * @param query CSS query to match siblings against
         * @return all previous element siblings.
         */
        public Elements prevAll(String query) {
            return siblings(query, false, true);
        }
    
        private Elements siblings(String query, boolean next, boolean all) {
            Elements els = new Elements();
            Evaluator eval = query != null? QueryParser.parse(query) : null;
            for (Element e : this) {
                do {
                    Element sib = next ? e.nextElementSibling() : e.previousElementSibling();
                    if (sib == null) break;
                    if (eval == null)
                        els.add(sib);
                    else if (sib.is(eval))
                        els.add(sib);
                    e = sib;
                } while (all);
            }
            return els;
        }
    
        /**
         * Get all of the parents and ancestor elements of the matched elements.
         * @return all of the parents and ancestor elements of the matched elements
         */
        public Elements parents() {
            HashSet<Element> combo = new LinkedHashSet<>();
            for (Element e: this) {
                combo.addAll(e.parents());
            }
            return new Elements(combo);
        }
    
        // list-like methods
        /**
         Get the first matched element.
         @return The first matched element, or <code>null</code> if contents is empty.
         */
        public Element first() {
            return isEmpty() ? null : get(0);
        }
    
        /**
         Get the last matched element.
         @return The last matched element, or <code>null</code> if contents is empty.
         */
        public Element last() {
            return isEmpty() ? null : get(size() - 1);
        }
    
        /**
         * Perform a depth-first traversal on each of the selected elements.
         * @param nodeVisitor the visitor callbacks to perform on each node
         * @return this, for chaining
         */
        public Elements traverse(NodeVisitor nodeVisitor) {
            NodeTraversor.traverse(nodeVisitor, this);
            return this;
        }
    
        /**
         * Perform a depth-first filtering on each of the selected elements.
         * @param nodeFilter the filter callbacks to perform on each node
         * @return this, for chaining
         */
        public Elements filter(NodeFilter nodeFilter) {
            NodeTraversor.filter(nodeFilter, this);
            return this;
        }
    
        /**
         * Get the {@link FormElement} forms from the selected elements, if any.
         * @return a list of {@link FormElement}s pulled from the matched elements. The list will be empty if the elements contain
         * no forms.
         */
        public List<FormElement> forms() {
            ArrayList<FormElement> forms = new ArrayList<>();
            for (Element el: this)
                if (el instanceof FormElement)
                    forms.add((FormElement) el);
            return forms;
        }
    
    }

    ##############################

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  • 原文地址:https://www.cnblogs.com/herd/p/15490422.html
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