读《研磨设计模式》-代码笔记-组合模式
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import java.util.ArrayList;import java.util.List;abstract class Component {public abstract void printStruct(String preStr);public void addChild(Component child) {throw new UnsupportedOperationException("addChild():not allowed.");}public void removeChild(Component child) {throw new UnsupportedOperationException("removeChild():not allowed.");}public Component getChild(int index) {throw new UnsupportedOperationException("getChild():not allowed.");}}class Leaf extends Component {private String name;public Leaf(String name) {this.name = name;}@Overridepublic void printStruct(String preStr) {System.out.println(preStr + "-" + name);}}class Composite extends Component {private String name;private List<Component> list;public Composite(String name) {this.name = name;}public void addChild(Component child) {if (list == null) {list = new ArrayList<Component>();}list.add(child);}public void removeChild(Component child) {if (list != null) {list.remove(child);}}@Overridepublic void printStruct(String preStr) {System.out.println(preStr + "+" + name);if (list != null) {preStr += " ";for (Component child : list) {child.printStruct(preStr);}}}}public class CompositePattern {public static void main(String[] args) {Component root = new Composite("服装");Component c1 = new Composite("男装");Component c2 = new Composite("女装");// 定义所有的叶子对象Component leaf1 = new Leaf("衬衣");Component leaf2 = new Leaf("夹克");Component leaf3 = new Leaf("裙子");Component leaf4 = new Leaf("套装");// 按照树的结构来组合组合对象和叶子对象root.addChild(c1);root.addChild(c2);c1.addChild(leaf1);c1.addChild(leaf2);c2.addChild(leaf3);c2.addChild(leaf4);// 调用根对象的输出功能来输出整棵树root.printStruct("");}}