Threads in UIMA

["Howard G." <ho...@yahoo.com>]

I have a question about threads in UIMA.  My application ("Main thread") starts an UIMA Collection Processing Engine (CPE), which contains a Collection-Reader and several Annotators.   Here is my code for starting the CPE:

public class UimaRunCPE extends Thread {
	
  /**
   * The CPE instance.
   */
  private CollectionProcessingEngine mCPE;

    public void runCPE() throws Exception { 
    	
    // parse CPE descriptor
    CpeDescription cpeDesc = UIMAFramework.getXMLParser().parseCpeDescription(
            new XMLInputSource(pathToDescriptor));

    // instantiate CPE
    mCPE = UIMAFramework.produceCollectionProcessingEngine(cpeDesc);

    // Create and register a Status Callback Listener
    mCPE.addStatusCallbackListener(new StatusCallbackListenerImpl());

    // Start Processing
    mCPE.process();
    
    System.out.println("CPE ended\n");
        
   }
}   


As I understand it (I stepped thru it in debug-mode in Eclipse), the CPE works like this -
--
1.  all the Annotator.initialize()'s  are done in "Main thread"

2. when mCPE.process() is called,  these threads are created---
	BaseCPMImpl-Thread
	CPMEngine Thread
	Processing Pipeline#1 Thread
	
3. the Collection-Reader runs in its own thread

4. the Annotator.process() methods run in the Processing Pipeline#1 Thread

5. when all Annotators are done, Processing Pipeline#1 Thread and CPMEngine Thread go away.  Control goes to BaseCPMImpl-Thread.collectionProcessComplete().  When that's done, all processing is over.  

My problem is this:  in Main-thread, mCPE.process() returns right away; it does not wait around to make sure that the CPE finished OK.  I need a way to do that.  It would work if Main-thread could do a join() on BaseCPMImpl-Thread, but I don't see any way to do that.

Any ideas?

Re: Threads in UIMA

["Howard G." <ho...@yahoo.com>]

Sounds good, I'll try it -- Thanks!


--- On Tue, 12/30/08, Adam Lally <al...@alum.rpi.edu> wrote:

> From: Adam Lally <al...@alum.rpi.edu>
> Subject: Re: Threads in UIMA
> To: uima-user@incubator.apache.org, howardg22@yahoo.com
> Date: Tuesday, December 30, 2008, 5:57 PM
> On Tue, Dec 30, 2008 at 5:17 PM, Howard G.
> <ho...@yahoo.com> wrote:
> > My problem is this:  in Main-thread, mCPE.process()
> returns right away; it does not wait around to make sure
> that the CPE finished OK.  I need a way to do that.  It
> would work if Main-thread could do a join() on
> BaseCPMImpl-Thread, but I don't see any way to do that.
> >
> > Any ideas?
> >
> 
> Hi Howard,
> 
> You can do this by waiting for the the
> StatusCallbackListener's
> collectionProcessComplete() method to be called.  For
> example the main
> thread could call wait() on the StatusCallbackListenerImpl
> instance,
> and then
> StatusCallbackListenerImpl.collectionProcessComplete() can
> call notifyAll.
> 
>  -Adam

Re: Threads in UIMA

[Adam Lally <al...@alum.rpi.edu>]

On Tue, Dec 30, 2008 at 5:17 PM, Howard G. <ho...@yahoo.com> wrote:
> My problem is this:  in Main-thread, mCPE.process() returns right away; it does not wait around to make sure that the CPE finished OK.  I need a way to do that.  It would work if Main-thread could do a join() on BaseCPMImpl-Thread, but I don't see any way to do that.
>
> Any ideas?
>

Hi Howard,

You can do this by waiting for the the StatusCallbackListener's
collectionProcessComplete() method to be called.  For example the main
thread could call wait() on the StatusCallbackListenerImpl instance,
and then StatusCallbackListenerImpl.collectionProcessComplete() can
call notifyAll.

 -Adam