how to run a javascript function asynchronously, without using setTimeout?

Question

its a server side Javascript (rhino engine), so setTimeout is not available. how to run a function asynchronously?

score 42 · Answer 1 · answered Apr 24 '11 at 00:32

42

You can use java.util.Timer and java.util.TimerTask to roll your own set/clear Timeout and set/clear Interval functions:

var setTimeout,
    clearTimeout,
    setInterval,
    clearInterval;

(function () {
    var timer = new java.util.Timer();
    var counter = 1; 
    var ids = {};

    setTimeout = function (fn,delay) {
        var id = counter++;
        ids[id] = new JavaAdapter(java.util.TimerTask,{run: fn});
        timer.schedule(ids[id],delay);
        return id;
    }

    clearTimeout = function (id) {
        ids[id].cancel();
        timer.purge();
        delete ids[id];
    }

    setInterval = function (fn,delay) {
        var id = counter++; 
        ids[id] = new JavaAdapter(java.util.TimerTask,{run: fn});
        timer.schedule(ids[id],delay,delay);
        return id;
    }

    clearInterval = clearTimeout;

})()

answered Apr 24 '11 at 00:32

Weston C

3,642
2
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1

Whit your code snippet, i was able to run Jasmine tests inside Rhino without the need of EnvJS. Thanks! – Gian Marco May 28 '11 at 15:25
I wish I could give you 100 upvotes, very awesome. Thanks so much. – Upgradingdave Aug 12 '11 at 17:03
2

Awesome. Thanks! To be fully compatibile with browsers, you need to handle omission of delay as well. MDN says that the minium delay as per the HTML5 spec is 4ms, so add the following: if (delay == null) { delay = 4; } – Brandon Bloom Apr 20 '12 at 10:08
@DaveParoulek You can give a bounty to Weston ;) – Stephan Feb 16 '14 at 17:40
3

**NOTA:** Rhino 1.7R4 has a bug that prevents the code in this answer to run. Either downgrade to 1.7R3 or use a newer version. (Check this discussion for details on newer versions: https://groups.google.com/d/msg/mozilla-rhino/6vvcjg_7NNU/XnWEPEyfcfwJ) – Stephan Feb 16 '14 at 18:47
4

@Alex, I created version that uses `ScheduledThreadPoolExecutor` instead of `Timer` and works in 1.7R4: https://gist.github.com/nbeloglazov/9633318 – Mikita Belahlazau Mar 19 '14 at 00:48

score 5 · Accepted Answer · edited Oct 16 '13 at 12:20

5

Have a look at the Multithreaded Script Execution example on the Rhino Examples page. Basically, JavaScript does not support threading directly, but you may be able to use a Java thread to achieve what you are looking for.

edited Oct 16 '13 at 12:20

nwellnhof

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answered Feb 14 '10 at 16:42

Justin Ethier

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score 3 · Answer 3 · edited May 23 '17 at 12:33

Another version using ScheduledThreadPoolExecutor, compatible with Rhino 1.7R4 and proposed by @Nikita-Beloglazov:

var setTimeout, clearTimeout, setInterval, clearInterval;

(function () {
    var executor = new java.util.concurrent.Executors.newScheduledThreadPool(1);
    var counter = 1;
    var ids = {};

    setTimeout = function (fn,delay) {
        var id = counter++;
        var runnable = new JavaAdapter(java.lang.Runnable, {run: fn});
        ids[id] = executor.schedule(runnable, delay, 
            java.util.concurrent.TimeUnit.MILLISECONDS);
        return id;
    }

    clearTimeout = function (id) {
        ids[id].cancel(false);
        executor.purge();
        delete ids[id];
    }

    setInterval = function (fn,delay) {
        var id = counter++;
        var runnable = new JavaAdapter(java.lang.Runnable, {run: fn});
        ids[id] = executor.scheduleAtFixedRate(runnable, delay, delay, 
            java.util.concurrent.TimeUnit.MILLISECONDS);
        return id;
    }

    clearInterval = clearTimeout;

})()

Reference: https://gist.github.com/nbeloglazov/9633318

how to run a javascript function asynchronously, without using setTimeout?

3 Answers3

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