java手动实现集合(数组形式)

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直接上代码：

package bean;

import java.util.Iterator;

public class ListDemo<T> implements Iterable<T> {

    private Object[] obj;
    private int size;
    private Iterator<T> iterator;

    public int getSize() {
        return size+1;
    }

    public ListDemo(){
        iterator = new IteratorImpl();
        size = 0;
        obj = new Object[10];
    }

    public void addItem(Object o){
        if(size%10==9){
            Object[] objTemp = obj;
            obj = new Object[objTemp.length+10];
            for(int i=0;i<objTemp.length;++i){
                obj[i] = objTemp[i];
            }
        }
        obj[size] = o;
        size++;
    }

    public void remove(int index){
        obj[index] = null;
        size--;
    }

    public Iterator<T> getIterator(){
        return iterator;
    }

    @SuppressWarnings("unchecked")
    public T getObject(int index){
        if(index>size){
            System.err.println("超出范围！");
            throw new IndexOutOfBoundsException("超出范围！");
        }
        return (T) obj[index-1];
    }

    @Override
    public Iterator<T> iterator() {
        // TODO Auto-generated method stub
        return iterator;
    }

    private class IteratorImpl implements Iterator<T>{

        private int index = 0;

        @Override
        public boolean hasNext() {
            // TODO Auto-generated method stub
            return index != size;
        }

        @SuppressWarnings("unchecked")
        @Override
        public T next() {
            // TODO Auto-generated method stub
            return (T)obj[index++];
        }

    }


}