Titanium Worker Thread Module

This is a Titanium module that provides a Web Worker like interface to applications built with Titanium.

This module is designed to be used when applications need to process multi-threaded application logic in the background from the main application thread. These threads are typically expensive, long-lived tasks which can be executed independent of the application processing or the main UI thread.

It is important to note that even though you can use this library to create worker threads, any processing or rendering that must be done by the UI will always continue to be single-threaded by the host OS and executed on the main "UI thread", regardless of how many parallel threads are used in the background.

Example

The following is a trivial echo background service. In your app.js, use the following:

var worker = require('ti.worker');

// create a worker thread instance
var task = worker.createWorker('echo.js');

// subscribe to any worker thread instance messages
task.addEventListener('message',function(event){

    // data that is sent will be in the data property
    alert(event.data);

    // stop terminating this thread instance
    task.terminate();
});

// send data to the worker thread which will be posted on the threads event queue
// you can send any data here
task.postMessage({
    msg:'Hello'
});

Now, in a separate file named echo.js, use the following:

// subscribe to events send with postMessage
worker.addEventListener('message',function(event){

    // send data back to any subscribers
    // pull data from the event from the data property
    worker.postMessage(event.data.msg);
});

Note: the worker global variable is always defined inside the worker thread execution context.

API

• postMessage - send a message to or from the worker thread. Send any data as the first argument.
• terminate - terminate the worker thread and stop as soon as possible processing.
• nextTick - this method is only available inside the worker instance and provides an ability to process the function passed on the next available thread event loop cycle.

Events

• message - receive an event. The data property of the event will contain as-is any data specified as the first argument.
• terminated - the worker thread was terminated.

Properties

The worker instance has only one property:

• url - the url of the worker thread JS file passed in during creation.

Warning

Concurrent programming is dangerous and error prone. We've designed this library to make it easier to build multi-threaded applications in Titanium. However, you should use at your own risk and make sure you do plenty of testing on different devices. You should also understand the concepts of concurrent programming before using this module.

Change Log

1.0 - June 4, 2012

This is the initial commit and it works only on iOS currently.

License

Copyright (c) 2012 by Appcelerator, Inc. All Rights Reserved. This code is licensed under the terms of the Apache Public License, version 2.