图1 组合模式【点击查看图片】
1,以公司职员为例的结构
package com.cnblogs.mufasa.demo3; import java.util.ArrayList; import java.util.List; public class Employee { private String name; private String dept; private int salary; private List<Employee> subordinates; //构造函数 public Employee(String name,String dept, int sal) { this.name = name; this.dept = dept; this.salary = sal; subordinates = new ArrayList<Employee>();//【核心所在】 } public void add(Employee e) { subordinates.add(e); } public void remove(Employee e) { subordinates.remove(e); } public List<Employee> getSubordinates(){ return subordinates; } public String toString(){ return ("Employee :[ Name : "+ name +", dept : "+ dept + ", salary :" + salary+" ]"); } }
package com.cnblogs.mufasa.demo3; public class CompositePatternDemo { public static void main(String[] args) { Employee CEO = new Employee("John","CEO", 30000); Employee headSales = new Employee("Robert","Head Sales", 20000); Employee headMarketing = new Employee("Michel","Head Marketing", 20000); Employee clerk1 = new Employee("Laura","Marketing", 10000); Employee clerk2 = new Employee("Bob","Marketing", 10000); Employee salesExecutive1 = new Employee("Richard","Sales", 10000); Employee salesExecutive2 = new Employee("Rob","Sales", 10000); CEO.add(headSales); CEO.add(headMarketing); headSales.add(salesExecutive1); headSales.add(salesExecutive2); headMarketing.add(clerk1); headMarketing.add(clerk2); //打印该组织的所有员工 System.out.println(CEO); for (Employee headEmployee : CEO.getSubordinates()) { System.out.println(headEmployee); for (Employee employee : headEmployee.getSubordinates()) { System.out.println(employee); } } } }
2,以枝叶为例的结构
package com.cnblogs.mufasa.demo1; import java.util.ArrayList; import java.util.List; public class ComponentDemo { public abstract class Component {//内部类 String name; public abstract void add(Component c); public abstract void remove(Component c); public abstract void eachChild(); } // 组合部件类 public class Leaf extends Component {//树叶 // 叶子节点不具备添加的能力,所以不实现 @Override public void add(Component c) { // TODO Auto-generated method stub System.out.println(""); } // 叶子节点不具备添加的能力必然也不能删除 @Override public void remove(Component c) { // TODO Auto-generated method stub System.out.println(""); } // 叶子节点没有子节点所以显示自己的执行结果 @Override public void eachChild() { // TODO Auto-generated method stub System.out.println(name + "执行了"); } } // 组合类 public class Composite extends Component {//树枝 // 用来保存节点的子节点 List<Component> list = new ArrayList<Component>(); // 添加节点 添加部件 @Override public void add(Component c) { // TODO Auto-generated method stub list.add(c); } // 删除节点 删除部件 @Override public void remove(Component c) { // TODO Auto-generated method stub list.remove(c); } // 遍历子节点 @Override public void eachChild() { // TODO Auto-generated method stub System.out.println(name + "执行了"); for (Component c : list) { c.eachChild(); } } } }
package com.cnblogs.mufasa.demo1; public class Client { public static void main(String[] args) { ComponentDemo demo = new ComponentDemo(); // 构造根节点 ComponentDemo.Composite rootComposite = demo.new Composite(); rootComposite.name = "根节点"; // 左节点 ComponentDemo.Composite compositeLeft = demo.new Composite(); compositeLeft.name = "左节点"; // 构建右节点,添加两个叶子几点,也就是子部件 ComponentDemo.Composite compositeRight = demo.new Composite(); compositeRight.name = "右节点"; ComponentDemo.Leaf leaf1 = demo.new Leaf(); leaf1.name = "右-子节点1"; ComponentDemo.Leaf leaf2 = demo.new Leaf(); leaf2.name = "右-子节点2"; compositeRight.add(leaf1); compositeRight.add(leaf2); // 左右节点加入 根节点 rootComposite.add(compositeRight); rootComposite.add(compositeLeft); // 遍历组合部件 rootComposite.eachChild(); } }
3,核心
将元素进行分级