HeadFirst设计模式_读书笔记_005_命令模式

命令模式：允许将发出请求的对象和接受并执行这些请求的对象分割开来，即实现请求调用者和请求接受者之间的解耦。定义：将请求封装成对象，以便使用不同的请求、队列或者日志来参数化其他对象。

 

调用命令的是Invoker,执行命令的实际上是Receiver。通过命令模式，将各种动作封装成Command,实现了Invoker和Receiver的彻底解耦。Invoker只管发出命令，Receiver只管执行相应的操作。

public interface Command {

	public void execute();
}

 

public class Dog {
	
	public void foundBone()
	{
		System.out.println("找骨头~~");
	}
	
	public void bark()
	{
		System.out.println("汪汪~~");
	}
	
	public void sing()
	{
		System.out.println("狗狗在唱歌~~");
	}

}

 

public class DogBarkCommand implements Command{

	private Dog dog;
	
	public DogBarkCommand(Dog dog)
	{
		this.dog = dog;
	}
	
	@Override
	public void execute() {
		dog.bark();
	}

}

 

public class DogFoundBoneCommand implements Command {

	private Dog dog;
	
	public DogFoundBoneCommand(Dog dog)
	{
		this.dog = dog;
	}
	@Override
	public void execute() {
		dog.foundBone();
	}

}

 

public class DogSingCommand implements Command{

	private Dog dog;
	
	public DogSingCommand(Dog dog)
	{
		this.dog = dog;
	}
	
	@Override
	public void execute() {
		this.dog.sing();	
	}

}

 

public class Invoker {
	
	Command command;
	
	public void setCommand(Command command)
	{
		this.command = command;
	}
	
	public void invoke()
	{
		this.command.execute();
	}

}

 

public class Test {

	public static void main(String args[])
	{
		Dog dog = new Dog();
		Command barkcommand = new DogBarkCommand(dog);
		Invoker invoker = new Invoker();
		invoker.setCommand(barkcommand);
		invoker.invoke();
	}
}