Java 命令模式

 Java設計模式 - 命令模式

命令模式是數據驅動設計模式它是行為模式之一。

請求被作為命令的對象包裝傳遞給invoker對象。

Invoker對象將命令傳遞到相應的對象并且該對象執(zhí)行該命令。

例子

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

interface Command {
  void execute();
}

class MouseCursor {
  private int x = 10;
  private int y = 10;
  public void move() {
    System.out.println("Old Position:"+x +":"+y);
    x++;
    y++;
    System.out.println("New Position:"+x +":"+y);
    
  }

  public void reset() {
    System.out.println("reset");
    x = 10;
    y = 10;
  }
}

class MoveCursor implements Command {
  private MouseCursor abcStock;

  public MoveCursor(MouseCursor abcStock) {
    this.abcStock = abcStock;
  }

  public void execute() {
    abcStock.move();
  }
}

class ResetCursor implements Command {
  private MouseCursor abcStock;

  public ResetCursor(MouseCursor abcStock) {
    this.abcStock = abcStock;
  }

  public void execute() {
    abcStock.reset();
  }
}

class MouseCommands {
  private List<Command> orderList = new ArrayList<Command>();

  public void takeOrder(Command order) {
    orderList.add(order);
  }

  public void placeOrders() {
    for (Command order : orderList) {
      order.execute();
    }
    orderList.clear();
  }
}

public class Main {
  public static void main(String[] args) {
    MouseCursor cursor = new MouseCursor();

    MoveCursor moveCursor = new MoveCursor(cursor);
    ResetCursor resetCursor = new ResetCursor(cursor);

    MouseCommands commands= new MouseCommands();
    commands.takeOrder(moveCursor);
    commands.takeOrder(resetCursor);

    commands.placeOrders();
  }
}

上面的代碼生成以下結果。