Java:使用 onComplete 回调简单实现命令模式？

Question

有人可以指出在哪里可以找到带有 onComplete 回调的命令模式的实现吗？例如可以在串行宏命令中使用该回调？

Answer 1

试试这个

abstract class Command {
    final public void execute(){
          run();
          onComplete();
    }
    protected abstract void run();
    protected abstract void onComplete();
}
//usage
abstract class HiCommand extends Command {
    protected void run(){
        System.out.println("Hi, ");
    }

    protected abstract void onComplete();
}

new HiCommand(){
    @Override
    protected void onComplete() {
        System.out.println("world");
    }
}.execute();

或者这个

interface WhenDone{
    void onComplete();
}

abstract class Command {
    private final WhenDone callback;
    protected Command(WhenDone callback){
        this.callback = callback;
    }
    final public void execute(){
          run();
          callback.onComplete();
    }
    protected abstract void run();
}
//usage
class PrintHi extends Command {
    protected PrintHi(WhenDone callback){
        super(callback);
    }

    protected void run(){
        System.out.println("Hi, ");
    }
}

class PrintWorld implements WhenDone {
    public void onComplete(){
        System.out.println("world!");
    }
}
//somewhere
new PrintHi(new PrintWorld()).execute();

使用示例并非来自现实生活。也许，您应该通过创建 CommandManager 将创建和调用执行分开。