设计模式7：Decorator

Node.java:

package gendwang.cisco.com;

public class Node 
{
	int value;
	Node next;
}

List.java:

package gendwang.cisco.com;

public interface List 
{
	public void addNode(int value);
	public void print();
}

LinkedList.java:

package gendwang.cisco.com;

public class LinkedList implements List
{
	private Node head = null;
	
	public void addNode(int value)
	{
		Node node = new Node();
		node.value = value;
		node.next = head;
		head = node;
	}
	
	public void print()
	{
		Node tmp = head;
		while(tmp != null)
		{
			System.out.print(tmp.value + " ");
			tmp = tmp.next;
		}
	}
}

DecoratorList.java:

package gendwang.cisco.com;

public class DecoratorList implements List
{
	private List list;
	
	public DecoratorList(List list)
	{
		this.list = list;
	}
	
	public void addNode(int value)
	{
		list.addNode(value);
	}
	
	public void print()
	{
		list.print();
	}
}

CountedList.java:

package gendwang.cisco.com;

public class CountedList extends DecoratorList 
{
	private int size = 0;
	
	public CountedList(List list)
	{
		super(list);
	}
	
	public void addNode(int value)
	{
		size++;
		super.addNode(value);
	}
	
	public void printSize()
	{
		System.out.println("size is " + size);
	}
}

Test.java:

package gendwang.cisco.com;

public class Test
{
	public static void main(String[] args) 
	{
		List list = new LinkedList();
		CountedList countedList = new CountedList(list);
		
		countedList.addNode(6);
		countedList.print();
		countedList.printSize();
		
		countedList.addNode(7);
		countedList.print();
		countedList.printSize();
		
		countedList.addNode(10);
		countedList.print();
		countedList.printSize();
	}

}