java - 向主 java 发送事件

Question

我有一个CountDownTimer类，当它完成倒计时时，它应该向主java(或任何使用它的类)分派(dispatch)一个事件，让它知道它已经完成。

这是我的类(class):

import com.google.gwt.user.client.Timer;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.ui.Label;

public class CountTimer {

    private Label targetText;
    private String direction;
    private int minutes;
    private int seconds;
    private int totalSeconds;
    private int timeTotal;
    private int timeLoaded;
    private Boolean test;

    Timer timer;


    public CountTimer(int min,int sec,String dir,Label targetTextField)
    {
        minutes = min * 60;
        seconds = sec;
        timeTotal = minutes + seconds;
        if (dir == "down") {
            totalSeconds = minutes + seconds;
        }
        else {
            totalSeconds = 0;
        }
        if (targetTextField != null) {
            targetText = targetTextField;
        }
        direction = dir;
    }

    public void start()
    {
        timer = new Timer(){
            public void run(){  
                timeLoaded +=  1;

                if (direction == "up") {
                    totalSeconds++;
                }
                else {
                    totalSeconds--;
                }

                seconds = totalSeconds % 60;
                minutes = (int) Math.floor(totalSeconds / 60);
                String minutesDisplay = (minutes < 10) ? "0" + Integer.toString(minutes) : Integer.toString(minutes);
                String secondsDisplay= (seconds < 10) ? "0" + Integer.toString(seconds): Integer.toString(seconds);
                if (targetText != null) {
                    targetText.setText( minutesDisplay + ":" + secondsDisplay);
                }
                if (test=true)  {
                    consoleLog(minutesDisplay + ":" + secondsDisplay);  
                }

                if(timeTotal == timeLoaded) {
                    //DISPATCH CUSTOM EVENT TO MAIN.JAVA HERE
                    Window.alert("OK");
                    timer.cancel();
                }
            }
        };

        timer.scheduleRepeating(1000);        
    }

    public int getTimeTotal()
    {
        return timeTotal;
    }

    public int getTimeLoaded()
    {
        return timeLoaded;
    }

    public int getProg()
    {
        return (int) Math.floor(timeLoaded/timeTotal*100);
    }

    public native final void consoleLog(String msg)/*-{
    console.log(msg);
}-*/;

}

请帮忙，我该怎么做？

Answer 1

我相信您正在寻求实现发布-订阅模式。 http://en.wikipedia.org/wiki/Publish%E2%80%93subscribe_pattern

您可以允许订阅者在您的对象上注册。一旦您完成操作，它就可以通知订阅者操作​​已完成。

示例:

public interface Subscriber {
    public void notify();
}

public class Publisher {
    private ArrayList<Subscriber> subscribers = new ArrayList<>();

    public void addSubscriber(Subscriber s) {
        subscribers.add(s);
    }

    public void doWork() {
        System.sleep(100);
            notifyAll();
    }

    private void notifyAll() {
        for(Subscriber s : subscribers) {
            s.notify();
        }
    }
}