组合模式

public class TreeNode {
	private String name;
	private TreeNode parent;
	private Vector<TreeNode> children = new Vector<TreeNode>();
	public TreeNode(String name){
		this.name = name;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public TreeNode getParent() {
		return parent;
	}
	public void setParent(TreeNode parent) {
		this.parent = parent;
	}
	//添加孩子节点
	public void add(TreeNode node){
		children.add(node);
	}
	//删除孩子节点
	public void remove(TreeNode node){
		children.remove(node);
	}
	//取得孩子节点
	public Enumeration<TreeNode> getChildren(){
		return children.elements();
	}
}

public class Tree {
	TreeNode root = null;
	public Tree(String name) {
		root = new TreeNode(name);
	}
	public static void main(String[] args) {
		Tree tree = new Tree("A");
		TreeNode nodeB = new TreeNode("B");
		TreeNode nodeC = new TreeNode("C");
		
		nodeB.add(nodeC);
		tree.root.add(nodeB);
		System.out.println("build the tree finished!");
	}
}

使用场景：将多个对象组合在一起进行操作，常用于表示树形结构中，例如二叉树，数等。