SDP04-04例子代码.rar

interface MyCollection { MyIterator createIterator(); } interface MyIterator { void first(); void next(); boolean isLast(); Object currentItem(); } class NewCollection implements MyCollection { private Object[] obj={"dog","pig","cat","monkey","pig"}; public MyIterator createIterator() { return new NewIterator(); } private class NewIterator implements MyIterator { private int currentIndex=0; public void first() { currentIndex=0; } public void next() { if(currentIndex<obj.length) { currentIndex++; } } public void previous() { if(currentIndex>0) { currentIndex--; } } public boolean isLast() { return currentIndex==obj.length; } public boolean isFirst() { return currentIndex==0; } public Object currentItem() { return obj[currentIndex]; } } } class Client { public static void process(MyCollection collection) { MyIterator i=collection.createIterator(); while(!i.isLast()) { System.out.println(i.currentItem().toString()); i.next(); } } public static void main(String a[]) { MyCollection collection=new NewCollection(); process(collection); } }