設計模式：行爲模式 - 命令模式

命令模式：將一個請求封裝爲一個對象，從而使你可用不同的請求對客戶進行參數化；對請求排隊或記錄請求日誌，以及支持可撤銷的操作

 

UML：

 

JAVA：

public class CommandTest {
    public static void main(String[] args) {
        Receiver r = new Receiver();
        Command c = new ConcreteCommand(r);
        Invoker i = new Invoker();
        i.setCommand(c);
        i.executeCommand();
    }
}

abstract class Command{
    protected Receiver receiver;

    public Command(Receiver receiver) {
        this.receiver = receiver;
    }

    public abstract void execute();
}
class ConcreteCommand extends Command{

    public ConcreteCommand(Receiver receiver) {
        super(receiver);
    }

    @Override
    public void execute() {
        receiver.Action();
    }
}

class Invoker{
    private Command command;

    public void setCommand(Command command) {
        this.command = command;
    }
    public void executeCommand(){
        command.execute();
    }
}

class Receiver{
    public void Action(){
        System.out.println("執行請求");
    }
}