数组实现顺序表

public class <AnyType> implements Iterable<AnyType> {
    private static final int DEFAULT_CAPACITY = 10;
    private int thesize;
    private AnyType[] theItems;
    public (){
        clear();
    }
    public void clear(){
        thesize = 0;
        ensureCapacity(DEFAULT_CAPACITY);
    }
    public int size(){
        return thesize;
    }
    public boolean isEmpty(){
        return size()==0;
    }
    public void trimTosize(){
        ensureCapacity(size());
    }
    public AnyType get(int idx){
        if(idx < 0 && idx >= size()){
            throw new ArrayIndexOutOfBoundsException();
        }
        return theItems[idx];
    }
    public AnyType set(int idx, AnyType newVal){
        if(idx < 0 && idx >= size()){
            throw new ArrayIndexOutOfBoundsException();
        }
        AnyType old = theItems[idx];
        theItems[idx] = newVal;
        return old;
    }
    
    * 数组过小时对数组进行扩容
    * @param newCapacity 新的数组大小
    */
    public void ensureCapacity(int newCapacity){
        if (newCapacity<thesize)
            return;
        AnyType[] old = theItems;
        theItems = (AnyType[]) new Object[newCapacity];
        for (int i = 0; i < size(); i++) {
            theItems[i] = old[i];
        }
    }
    public boolean add(AnyType x){
        add(size(),x);
        return true;
    }
    
    * 指定位置添加元素
    * @param idx 指定位置
    * @param x 添加元素
    */
    public void add(int idx, AnyType x){
        if (theItems.length==size())
            ensureCapacity(size()*2+1);
        for (int i = thesize; i>idx; i--){
            theItems[i]=theItems[i-1];
        }
        theItems[idx] = x;
        thesize++;
    }
    public AnyType remove(int idx){
        AnyType removedItem = theItems[idx];
        for (int i = idx; i<size(); i++){
            theItems[i]=theItems[i+1];
        }
        thesize--;
        return removedItem;
    }
    
    * Returns an iterator over elements of type {@code T}.
    *
    * @return an Iterator.
    */
    
    public Iterator<AnyType> iterator() {
        return new ArrayListIterator() ;
    }
    private class ArrayListIterator implements java.util.Iterator<AnyType>{
        private int current = 0;
        
        public boolean hasNext() {
            return current<size();
        }
        
        public AnyType next() {
            if (!hasNext()){
                throw new java.util.NoSuchElementException();
            }
            return theItems[current++];
        }
        
        public void remove() {
            MyArrayList.this.remove(--current);
        }
    }
}