组合模式- 2020-12-02 22:54- 设计模式

组合模式 一般用于处理树型结构

demo

  1. /**
  2.  * 节点
  3.  *
  4.  * @author Bai
  5.  * @date 2020/12/2 22:30
  6.  */
  7. @Data
  8. public class Node {
  9.     /**
  10.      * 节点名称
  11.      */
  12.     private String name;
  14.     public Node(String name) {
  15.         this.name = name;
  16.     }
  17. }
  2. /**
  3.  * @author Bai
  4.  * @date 2020/12/2 22:31
  5.  */
  6. public class BranchNode extends Node {
  7.     public BranchNode(String name) {
  8.         super(name);
  9.     }
  11.     /**
  12.      * 子节点
  13.      */
  14.     private List<Node> childNodes = new ArrayList<>();
  16.     public BranchNode add(Node node) {
  17.         childNodes.add(node);
  18.         return this;
  19.     }
  21.     public List<Node> getChildNodes() {
  22.         return childNodes;
  23.     }
  25.     public void setChildNodes(List<Node> childNodes) {
  26.         this.childNodes = childNodes;
  27.     }
  28. }
  1.  @Test
  2.     public void demo() {
  3.         //模拟一次 目录路径， 并且打印出 从根目录到子目录的 所有路径
  4.         //根节点
  5.         BranchNode root = new BranchNode("root");
  6.         //根节点下有两个子级目录 chapter1 chapter2
  7.         BranchNode chapter1 = new BranchNode("chapter1");
  8.         //chapter1 下有两个子级目录
  9.         BranchNode chapter1_1 = new BranchNode("chapter1_1");
  10.         //chapter1_1下有一个子级
  11.         Node chapter1_1_1 = new Node("chapter1_1_1");
  12.         chapter1_1.add(chapter1_1_1);
  13.         //chapter1_2为叶子目录
  14.         Node chapter1_2 = new Node("chapter1_2");
  15.         chapter1.add(chapter1_1).add(chapter1_2);
  17.         //chapter2 下有三个子级目录
  18.         BranchNode chapter2 = new BranchNode("chapter2");
  19.         //chapter2 下有两个子级目录
  20.         BranchNode chapter2_1 = new BranchNode("chapter2_1");
  21.         //chapter2_1 下有一个子级
  22.         Node chapter2_1_1 = new Node("chapter2_1_1");
  23.         chapter2_1.add(chapter2_1_1);
  24.         //chapter1_2为叶子目录
  25.         Node chapter2_2 = new Node("chapter1_2");
  26.         Node chapter2_3 = new Node("chapter2_3");
  27.         chapter2.add(chapter2_1).add(chapter2_2).add(chapter2_3);
  29.         root.add(chapter1);
  30.         root.add(chapter2);
  32.         //递归打印出来每个节点
  33.         print(root, 0);
  34.     }
  36.     private void print(Node root, int depth) {
  37.         for (int i = 0; i < depth; i++) {
  38.             System.out.print("——");
  39.         }
  40.         System.out.println(root.getName());
  41.         if (root instanceof BranchNode) {
  42.             BranchNode branchNode = (BranchNode) root;
  43.             for (Node childNode : branchNode.getChildNodes()) {
  44.                 print(childNode, depth + 1);
  45.             }
  46.         }
  47.     }

**

  1. root
  2. ——chapter1
  3. ————chapter1_1
  4. ——————chapter1_1_1
  5. ————chapter1_2
  6. ——chapter2
  7. ————chapter2_1
  8. ——————chapter2_1_1
  9. ————chapter1_2
  10. ————chapter2_3

**