Java-数据结构-Bag（单链表）

package model.API;


import java.util.Iterator;
import java.util.NoSuchElementException;

public class bag<E> implements Cloneable, Iterable<E> {
    private E[] data;
    private int manyItems;

    public Iterator<E> iterator() {
        return new bagIterator();
    }

    private class bagIterator implements Iterator<E> {
        private int current = 0;

        public boolean hasNext() {
            return current < size();
        }

        public E next() {
            if (!hasNext()) {
                throw new NoSuchElementException();
            }
            return data[current++];
        }

    }

    public bag() {
        final int INITIAL_CAPACITY = 10;
        manyItems = 0;
        data = (E[]) new Object[INITIAL_CAPACITY];
    }

    public bag(int initialCapacity) {
        if (initialCapacity < 0)
            throw new IllegalArgumentException("The initialCapacity is negative: " + initialCapacity);
        manyItems = 0;
        data = (E[]) new Object[initialCapacity];
    }

    public int size() {
        return manyItems;
    }

    public int getCapacity() {
        return data.length;
    }

    public void ensureCapacity(int minimumCapacity) {
        E biggerArray[];
        if (data.length < minimumCapacity) {
            biggerArray = (E[]) new Object[minimumCapacity];
            System.arraycopy(data, 0, biggerArray, 0, manyItems);
            data = biggerArray;
        }
    }

    public void add(E element) {
        if (manyItems == data.length) {
            ensureCapacity((manyItems + 1) * 2);
        }
        data[manyItems++] = element;
    }

    public void addAll(bag<E> addend) {
        ensureCapacity(manyItems + addend.manyItems);
        System.arraycopy(addend.data, 0, data, manyItems, addend.manyItems);
        manyItems += addend.manyItems;
    }

    //相当于一个数组,能够传入0个至n个参数
    public void addMany(E... elements) {
        if (manyItems + elements.length > data.length) {
            ensureCapacity((manyItems + elements.length) * 2);
        }
        System.arraycopy(elements, 0, data, manyItems, elements.length);
        manyItems += elements.length;
    }

    public bag<E> clone() {
        bag<E> copy;
        try {
            copy = (bag<E>) super.clone();
        } catch (CloneNotSupportedException e) {
            throw new RuntimeException("This class does not implement Cloneable");
        }
        copy.data = data.clone();
        return copy;
    }

    public boolean remove(E target) {
        int index;
        for (index = 0; (index < manyItems) && !target.equals(data[index]); index++) ;//对象比较
        if (index == manyItems) return false;
        else {
            data[index] = data[--manyItems];
            return true;
        }
    }

    public int removeMany(E... targets) {
        int count = 0;
        for (E target : targets)
            if (remove(target))
                count++;
        return count;
    }

    public void trimToSize() {
        E[] trimmedArray;
        if (data.length != manyItems) {
            trimmedArray = (E[]) new Object[manyItems];
            System.arraycopy(data, 0, trimmedArray, 0, manyItems);
            data = trimmedArray;
        }
    }

}