Pass messages between main thread and FX application thread

Question

I'm launching an FX Application thread from a Main thread using Application.launch [outlined here: {thread:id=2530636}]
I'm trying to have the Aplication thread return information to the Main thread, but Application.launch returns void. Is there an easy way to communicate between the Main thread and the Application thread?
So far I have googled and found:
- MOM (Message Orientated Middleware)
- Sockets
Any thoughts/ideas/examples are appreciated - especially examples ;) - right now I am looking at using Sockets to show/hide the application and for passing data.
What is the preferred method? Are there others which I have not found (gasp) via Google?
Dave.
Edited by: cr0ck3t on 30-Apr-2013 21:04
Edited by: cr0ck3t on 30-Apr-2013 21:05

Answer 1

Is there an easy way to get a reference to these objects from both the Main thread and the FX Application thread - called via Application.launch() from the Main thread? Or do I have to use Sockets or MOM?Not much to do with concurrent programming is what I would call easy. It seems easy - but it's not.
You can kind of do what you are describing using Java concurrency constructs without using sockets or some Message Oriented Middleware (MOM) package.
With the Java concurrency stuff you are really implementing your own form or lightweight MOM.
If you have quite a complex application with lots of messages going back and forth then some kind of MOM package such as camel or ActiveMQ (http://camel.apache.org) is useful.
You can find a sample of various thread interactions with JavaFX here:
https://gist.github.com/jewelsea/5500981 "Simulation of dragons eating dwarves using multiple threads"
Linked code is just demo-ware to try out different concurrency facilities and not necessarily a recommended strategy.
If your curious, you could take a look at it and try to work out what it is, what it does and how it does it.
The main pattern followed is that from a blocking queue:
http://docs.oracle.com/javase/6/docs/api/java/util/concurrent/BlockingQueue.html
Note that once you call launch from the main thread, no subsequent statements in the main method will be run until the JavaFX application shuts down. So you can't really launch from the main thread and communicate with a JavaFX app from the main thread. Instead you need to spawn another thread (or set of threads) for communication with the JavaFX app.
But really, in most cases, the best solution with concurrency is not to deal with it at all (or at least as little as possible). Write everything in JavaFX, use the JavaFX animation framework for timing related stuff and use the JavaFX concurrency utilities for times when you really need multiple thread interaction.
http://docs.oracle.com/javafx/2/threads/jfxpub-threads.htm
To get further help, you might be better off describing exactly (i.e. really specific) what you are trying to do in a new question, perhaps with a sample solution in an sscce http://sscce.org