Command Pattern

May 10, 2021

커맨드 패턴

요청을(행위들을) 캡슐화하고 매개변수를 사용해서 여러가지 다른 요구사항(다양한 command)들을 수행하는데 용이한 디자인 패턴이다.
구성요소
- invoker
- receiver
- command
- concrete-command

다이어그램

예제 [Java]

Command interface command

interface Command {
  void execute();
}

Save Command concrete-command

public class SaveCommand implements Command {
  private Receiver receiver;

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

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

Update Command concrete-command

public class UpdateCommand implements Command {
  private Receiver receiver;

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

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

Receiver receiver

public class Receiver {
  public void saveReceive() {
    System.out.println("saveReceive!!"); 
  }

  public void updateReceive() {
    System.out.println("updateReceive!!!"); 
  }
}

Executor invoker

public class Executor {
  private final Command operation;

  public Executor(Command operation) {
    this.operation = operation;
  }

  public void invoke() {
    this.operation.execute();
  }
}

main 메소드

public static void main(String[] args) {
  Receiver receiver = new Receiver();
  Executor executor = new Executor(new SaveCommand(receiver));
  executor.invoke();
  
  executor = new Executor(new UpdateCommand(receiver));
  executor.invoke();
}