package test.edu.inter; 
 
public interface IteratorObj { 
  
  /** 
  * 移动到第一个元素 
  */ 
 public void first(); 
 /** 
  * 移动到下一个元素 
  */ 
 public boolean hasNextItem(); 
 /** 
  * 返还当前元素 
  */ 
 public Object currentItem(); 
 
} 


package test.edu.inter; 
 
public interface DataSet { 
 public IteratorObj getIterator(); 
} 



package test.edu.inter; 
 
 
public class Iterator1 implements IteratorObj { 
  
 private Dataobj set; 
 private int size; 
 private int index=0; 
  
 public Iterator1(Dataobj set){ 
  this.set = set; 
  this.size = set.getSize(); 
 } 
 
 @Override 
 public void first() { 
  // TODO Auto-generated method stub 
  this.index = 0; 
 } 
  
 @Override 
 public boolean hasNextItem() { 
  if(index<size){ 
   return true; 
  } 
  return false; 
 } 
 
 @Override 
 public Object currentItem() { 
  Object ob = set.getItem(index); 
  if(index<size){ 
   index++; 
  } 
  return ob; 
 } 
} 



package test.edu.inter; 
 
public class Dataobj implements DataSet { 
  
 private Object[] objArray = null; 
  /** 
   * 传入聚合对象 
   */ 
 public Dataobj(Object[] objArray){ 
   this.objArray = objArray; 
  } 
  
 @Override 
 public IteratorObj getIterator() { 
  return new Iterator1(this); 
 } 
  
 public Object getItem(int index){ 
  return objArray[index]; 
 } 
 public int getSize(){ 
  return objArray.length; 
 } 
} 



package test.edu.inter; 
 
public class Client { 
 
 /** 
  * @param args 
  */ 
 public static void main(String[] args) { 
  // TODO Auto-generated method stub 
  String[] str={"12312","dasda","dasd","12d","asd"}; 
  Dataobj ao = new Dataobj(str); 
  IteratorObj io = ao.getIterator(); 
  while(io.hasNextItem()){ 
   System.out.println(io.currentItem()); 
  } 
 } 
} 

12312 
dasda 
dasd 
12d 
asd 

import java.util.Iterator;
public interface Itr extends Iterator{
   //再次调用next()方法时所用的指标
   int cursor = 0;
   //最近一次调用时所用的指标
   int lastRet = -1;
   int expectedModCount = modCount;
   public boolean hasNext(){
     return cursor!=size();
   }
   public Object next(){
     try{
       Object next = get(cursor);
       checkForComodification();
       lastRet = cursor++;
       return next;
     }catch(IndexOutOfBoundsException e){
       checkForComodification();
       throw new NoSuchElementException();
     }
   }
   //删除最后遍历过的元素，remove()方法只能删除最后遍历的元素
   public void remove(){
     if(lastRet ==-1)
       throw new IllegalStateException();
     checkForComodification();
     try{
       AbstractList.this.remove(lastRet);
       if(lastRet<cursor)
          cursor--;
       lastRet = -1;
       expectedModCount = modCount;
     }catch(IndexOutOfBoundsException e){
       throw new ConcurrentModificationException();
     }
   }
   public void checkForComodification(){
     if(modCount!=expectedModCount)
       throw new ConcurrentModificationException();
   }
}