Java组合模式（思维导图）

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