Java 組合模式

Java設(shè)計(jì)模式 - 組合模式

組合模式是結(jié)構(gòu)型模式，因?yàn)樗鼊?chuàng)建了一組對(duì)象的樹結(jié)構(gòu)。

組合模式將一組對(duì)象視為單個(gè)對(duì)象。

組合模式使用一個(gè)類來表示樹結(jié)構(gòu)。

在組合模式中，我們創(chuàng)建一個(gè)包含自己對(duì)象的類的組。

例子

以下代碼使用Employee類來演示組合模式。

import java.util.ArrayList;
import java.util.List;

class Employee {
   private String name;
   private String title;
   private List<Employee> subordinates;

   public Employee(String name,String title) {
      this.name = name;
      this.title = title;
      subordinates = new ArrayList<Employee>();
   }

   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 : "+ title +subordinates +" ]";
   }   
}

public class Main {
   public static void main(String[] args) {
      Employee CEO = new Employee("John","CEO");

      Employee headSales = new Employee("Rob","Sales");

      Employee headMarketing = new Employee("Mike","Marketing");

      Employee programmer1 = new Employee("Lili","Programmer");
      Employee programmer2 = new Employee("Bob","Programmer");

      Employee tester1 = new Employee("Jack","Tester");
      Employee tester2 = new Employee("Tom","Tester");

      CEO.add(headSales);
      CEO.add(headMarketing);

      headSales.add(tester1);
      headSales.add(tester2);

      headMarketing.add(programmer1);
      headMarketing.add(programmer2);

      //print all employees of the organization
      System.out.println(CEO); 
      for (Employee headEmployee : CEO.getSubordinates()) {
         System.out.println(headEmployee);
         for (Employee employee : headEmployee.getSubordinates()) {
            System.out.println(employee);
         }
      }    
   }
}

上面的代碼生成以下結(jié)果。