ArrayList与LinkedList

package charpter3;
import java.util.Iterator;
import java.util.NoSuchElementException;

public class MyArrayList <AnyType> implements Iterable<AnyType> {
	
	private static final int DEFAULT_CAP = 10;
	
	private int theSize ;
	private AnyType [] theItems ;
	
	public MyArrayList(){
		clear() ;
	}
	public void clear (){
		theSize =0;
		ensureCap(DEFAULT_CAP);
	}
	
	public boolean isEmpty (){
		return size()==0;
	}
	
	public void trimToSize(){
		ensureCap(size()) ;
	}
	public AnyType get(int idx){
		if (idx<0|| idx>= size())
			throw new ArrayIndexOutOfBoundsException();
		return theItems[idx] ;
	}
	/**
	 * 返回了原来的值
	 */
	public AnyType set(int idx, AnyType newVal ){
		if (idx<0|| idx>=size()) 
			throw new ArrayIndexOutOfBoundsException() ;
		AnyType old = theItems[idx] ;
		theItems[idx] = newVal ;
		return old ;
	}
	
	public int  size(){
		return theSize ;
	}
	public void ensureCap(int newCap){
		if (newCap<theSize)
			return ;
		AnyType [] old = theItems ;
		theItems = (AnyType[]) new Object[newCap] ;
		for (int i=0;i<size() ; i++){
			theItems[i] = old[i];
		}
	}
	
	public boolean add (AnyType x ){
		add(size(), x);
		return true ;
	}
	
	public void add(int idx ,AnyType x ){
		if (theItems.length== size()) 
			ensureCap(size()*2+1);
		for (int i = theSize;i>idx;i--){
			theItems[i]= theItems[i-1]; //向后移动 
		}
		theItems[idx] = x;
		theSize++;
	}
	public AnyType remove (int idx){
		AnyType removedItem = theItems[idx] ;
		for (int i=idx ;i<size()-1 ; i++){ //后面的前移
			theItems [i] =theItems[i+1] ;
		}
		theSize --;
		return removedItem ;
	}
	public Iterator<AnyType> iterator() {
		// TODO Auto-generated method stub
		return new ArrayListIterator();
	}

	private class ArrayListIterator implements Iterator<AnyType>{
		
		private int current =0;
		
		public boolean hasNext() {
			// TODO Auto-generated method stub
			return current<size(); 
		}

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

		@Override
		public void remove() {
			MyArrayList.this.remove(--current) ;
		}

	}

}

class OuterClass {
    ...
    static class StaticNestedClass {
        ...
    }
    class InnerClass {
        ...
    }
}