Attach UncaughtExceptionHandler to a TimerTask

Question

Hi

Is it possible to attach an UncaughtExceptionHandler to a TimerTask? (Other than by calling Thread.setDefaultUncaughtExceptionHandler())

Cheers

Rich

Answer 1

You can write a TimerTask proxy that catches Throwable from run.

public final class TimerTaskCatcher extends TimerTask {
    private final TimerTask orig;
    private final Thread.UncaughtExceptionHandler handler;
    public TimerTaskCatcher(
        TimerTask orig, 
        Thread.UncaughtExceptionHandler handler
    } {
        if (orig == null || handler == null) {
            throw new NullPointerException();
        }
        this.orig = orig;
        this.handler = handler;
    }
    @Override public boolean cancel() {
        return orig.cancel();
    }
    @Override public void run() {
        try {
            orig.run();
        } catch (Throwable exc) {
            handler.uncaughtException(Thread.currentThread(), exc);
        }
    }
    @Override public long scheduledExecutionTime() {
        return orig.scheduledExecutionTime();
    }
}

BTW: You might want to consider using java.util.concurrent instead of Timer.

Answer 2

Yes, I think so. There's an instance method (setUncaughtExceptionHandler) in Thread class that set's the thread's UncaughtExceptionHandler.

In your run method of the TimerTask you can do something like this:

public void run() {
    Thread.currentThread().setUncaughtExceptionHandler(eh);
}