/** 
 * 自定义集合接口, 类似java.util.Collection 
 * 用于数据存储 
 * @author stone 
 * 
 */ 
public interface ICollection<T> { 
   
  IIterator<T> iterator(); //返回迭代器 
  void add(T t); 
  T get(int index); 
} 

/** 
 * 自定义迭代器接口 类似于java.util.Iterator 
 * 用于遍历集合类ICollection的数据 
 * @author stone 
 * 
 */ 
public interface IIterator<T> { 
  boolean hasNext(); 
  boolean hasPrevious(); 
  T next(); 
  T previous(); 
} 

/** 
 * 集合类， 依赖于MyIterator 
 * @author stone 
 */ 
public class MyCollection<T> implements ICollection<T> { 
 
  private T[] arys; 
  private int index = -1; 
  private int capacity = 5; 
   
  public MyCollection() { 
    this.arys = (T[]) new Object[capacity]; 
  } 
   
  @Override 
  public IIterator<T> iterator() { 
    return new MyIterator<T>(this); 
  } 
   
  @Override 
  public void add(T t) { 
    index++; 
    if (index == capacity) { 
      capacity *= 2; 
      this.arys = Arrays.copyOf(arys, capacity); 
       
    } 
    this.arys[index] = t; 
  } 
   
  @Override 
  public T get(int index) { 
    return this.arys[index]; 
  } 
   
} 

/* 
 * 若有新的存储结构，可new 一个ICollection， 对应的 new 一个IIterator来实现它的遍历 
 */ 
@SuppressWarnings({"rawtypes", "unchecked"}) 
public class Test { 
  public static void main(String[] args) { 
    ICollection<Integer> collection = new MyCollection<Integer>(); 
    add(collection, 3, 5, 8, 12, 3, 3, 5); 
    for (IIterator<Integer> iterator = collection.iterator(); iterator.hasNext();) { 
      System.out.println(iterator.next()); 
    } 
     
    System.out.println("-------------"); 
     
    ICollection collection2 = new MyCollection(); 
    add(collection2, "a", "b", "c", 3, 8, 12, 3, 5); 
    for (IIterator iterator = collection2.iterator(); iterator.hasNext();) { 
      System.out.println(iterator.next()); 
    } 
     
  } 
   
  static <T> void add(ICollection<T> c, T ...a) { 
    for (T i : a) { 
      c.add(i); 
    } 
  } 
} 

3 
5 
8 
12 
3 
3 
5 
------------- 
a 
b 
c 
3 
8 
12 
3 
5