[design pattern] [java] Decorator pattern

這種模式讓你不用修改現有的interface，
並且對其新添加功能，

重點在於Employee.java的第七行，
除了複寫walk的method，還添加了
run的method在裡面.




Human.java

package com.test.decoratorpattern;

public interface Human {

 void walk(String msg);
}

Man.java

package com.test.decoratorpattern;

public class Man implements Human{

 @Override
 public void walk(String msg) {
  System.out.println("class is Man , "+msg);
 }

}

ManDecorator.java

package com.test.decoratorpattern;

public class ManDecorator implements Human {

 protected Human decoratedHuman;

 public ManDecorator(Human decoratedHuman) {
  this.decoratedHuman = decoratedHuman;
 }

 public void walk(String msg) {
  decoratedHuman.walk("class is ManDecorator:"+msg);
 }

}

Employee.java

package com.test.decoratorpattern;

public class Employee extends ManDecorator {

 public Employee(Human decoratedHuman) {
  super(decoratedHuman);
  // TODO Auto-generated constructor stub
 }

 @Override
 public void walk(String msg) {
  decoratedHuman.walk(msg);
  run(decoratedHuman);
 }

 private void run(Human decoratedHuman) {
  System.out.println("class is Employee: Run");
 }

}

testDecorator.java

package com.test.decoratorpattern;

public class testDecorator {

 public static void main(String[] args) {
  // TODO Auto-generated method stub

  Human man = new Man();
  man.walk(" man ");
  
  Human employee = new Employee(new Man());
  employee.walk(" employee ");

        
 }

}

Console

class is Man ,  man 
class is Man ,  employee 
class is Employee: Run