CODEWITHSUNDEEP
javaswingjakarta-ee
Mellon
Mellon

Reputation: 38882

How to optimize my code to handle this special event

My program listens to 3 types of events: ADD, DELETE, REFRESH which is triggered by a 3rd party library component on UI. My listener looks like this:

//the timestamp is the time when the event occurs
public void listenToEvent(Event event, long timestamp){
     if(event.getName().equals("ADD")){
           //handle ADD event

     }else if(event.getName().equals("DELETE")){
          //handle DELETE event

    }else if(event.getName().equals("REFRESH")){
          //handle REFRESH event

    }

}

The code works fine for each event, except a little problem with REFRESH event:

when refresh happened on UI, the 3rd party lib component fires consecutive 3 events in a short time, that's: ADD->DELETE->REFRESH, in this case my listener thinks there are 3 events, but actually it is only a refresh action on UI.

How can I optimise my code so that when ADD->DELETE->REFRESH happens consecutively very quickly, my listener could be smart enough to know it is only a REFRESH?

(ADD and DELETE events are NOT instances of the REFRESH event)

Upvotes: 2

Views: 88

Answers (3)

Mellon
Mellon

Reputation: 38882

After some thinking, I came up with my own solution:

That's in ADD & DELETE condition, I use Thread.sleep(1000), then get the system time, after which I compare the latest system time get in REFRESH condition, if the difference is within 1sec, then it is a refresh event.

private long timeout = 1000;
private long addEventTime;
private long deleteEventTime;
private long refreshEventTime;

public void listenToEvent(Event event, long timestamp){
     if(event.getName().equals("ADD")){
           Thread.sleep(timeout);
           addEventTime = System.currentTimeMillis();
           if((refreshEventTime - addEventTime) >timout){
               //handle ADD event
            }


     }else if(event.getName().equals("DELETE")){
           Thread.sleep(timeout);
           deleteEventTime = System.currentTimeMillis();
           if((refreshEventTime - deleteEventTime) >timout){
               //handle DELETE event
            }


    }else if(event.getName().equals("REFRESH")){
          refreshEventTime = System.currentTimeMillis();
          //handle REFRESH event

    }

}

Any guru has any comment on my solution ?

Upvotes: 2

NeplatnyUdaj
NeplatnyUdaj

Reputation: 6242

As I already said in the comments, the piece of code I posted below is working(tested). You will probably need some tweaking of the REFRESH_TIMEOUT and probably make it thread-safe, but I've tested the basic idea:

"If ADD event comes, create a timer for it. When DELETE comes, check if there is a timertask already. If it's not-> process DELETE. If there is -> process REFRESH. If the timer expires-> process ADD"

It's a bit of a hack, but with the information you gave, I think this solution may be the easiest thing to do. You may get into a problems if the proper events are coming faster then is your REFRESH_TIMEOUT. In that case, the logic will get a bit more complicated.

long REFRESH_TIMEOUT=100;
Timer timer = null;
MyTask myTask = null;
public void listenToEvent(Event event, long timestamp){
    if(event.getName().equals("ADD")){
        timer = new Timer();
        timer.schedule(myTask = new MyTask(event), REFRESH_TIMEOUT);
    }
    if(event.getName().equals("DELETE")){
        if (myTask!=null && !myTask.expired){
            processRefresh(event);
            timer.cancel();
        }else{
            processDelete(event);
        }
    }
}

private static class MyTask extends TimerTask {
    Event event;
    boolean expired;
    public MyTask(Event event){
        this.event=event;
    }
    @Override
    public void run() {
        expired=true;
        processAdd(event);
    }
}

private void processAdd(Event e){
    ...
}
private void processDelete(Event e){
    ...
}
private void processRefrsh(Event e){
    ...
}

Upvotes: 2

gabizou
gabizou

Reputation: 113

If the event api is well thought imo, I'd think that an ADD event could be an instance of a REFRESH event.

An example of this would be:

//AccidentAPI provided by FooBar Corp.
public CarAccidentEvent extends AccidentEvent {

    private String carMake;

    public String getMake() {
        return carMake;
    }
}

So, your listener would be able to do something like this:

public void listenToAccidents(AccidentEvent e) {

    if (e instanceOf CarAccidentEvent) {
         doStuff();
    } else if (e instanceOf SkyJumpingEvent) {
         doOtherStuff();
    } else {
         blah();
    }
}

But again, this is going on the assumption that the ADD and DELETE events are instances of the REFRESH event. Though, perhaps their documentation would reveal something further about the EventAPI that may help answer the problem better.

Otherwise, you could add three attributes for the listener for the System's time in Millis which if the time in Millis is a difference greater than say 1ms, then process it, otherwise, go to the REFRESH case.

Upvotes: 0

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