设计模式 组件模式

先写一个抽象类，表示一部分

public abstract class Component {
	protected String name;
	
	public Component(String name)
	{
		this.name=name;
	}
	
	public abstract void Add(Component c);
	public abstract void Remove(Component c);
	public abstract void Display(int depth); 
}

再写叶子节点

public class Leaf extends Component{

	public Leaf(String name) {
		super(name);
		// TODO Auto-generated constructor stub
	}

	@Override
	public void Add(Component c) {
		// TODO Auto-generated method stub
		System.out.println("不能增加一个片叶子");
	}

	@Override
	public void Remove(Component c) {
		// TODO Auto-generated method stub
		System.out.println("不能移除一个片叶子");
	}

	@Override
	public void Display(int depth) {
		// TODO Auto-generated method stub	
		for(int i=0;i<depth;i++)
		{
			System.out.print('-');
		}
		System.out.println(name);
	}

}

import java.util.ArrayList;
import java.util.List;

public class Composite extends Component{

	private List<Component> children =new ArrayList<Component>();
	
	public Composite(String name) {
		super(name);
		// TODO Auto-generated constructor stub
	}

	@Override
	public void Add(Component c) {
		// TODO Auto-generated method stub
		children.add(c);
	}

	@Override
	public void Remove(Component c) {
		// TODO Auto-generated method stub
		children.remove(c);
	}

	@Override
	public void Display(int depth) {
		// TODO Auto-generated method stub
		for(int i=0;i<depth;i++)
		{
			System.out.print('-');
		}
		System.out.println(name);
		
		for (Component component : children) {
			component.Display(depth+2);;
		}
	}

}

在写测试类

public class Program {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Composite root = new Composite("root");
		root.Add(new Leaf("Leaf A"));
		root.Add(new Leaf("Leaf B"));
		
		Composite composite = new Composite("Composite X");
		composite.Add(new Leaf("Leaf XA"));
		composite.Add(new Leaf("Leaf XB"));
		
		root.Add(composite);
		
		Composite composite2 = new Composite("Composite XY");
		composite2.Add(new Leaf("Leaf XYA"));
		composite2.Add(new Leaf("Leaf XYB"));
		composite.Add(composite2);
		
		root.Add(new Leaf("Leaf C"));
		
		
		Leaf leaf =new Leaf("Leaf D");
		root.Add(leaf);
		root.Remove(leaf);
		
		
		
		
		
		root.Display(1);
	}

}