Description Ian Bull 2011-03-08 00:52:06 EST

On a 1.5 VM, the file level locking doesn't appear to 'lock' a location between threads in the same process. That is, if one thread calls lock(), and another thread calls isLocked(), on a 1.5 VM, the call to isLocked() will return *false*, whereas on a 1.6 VM the call to isLocked() will return *true*.

This code snippet demonstrates the problem:

public Object start(IApplicationContext context) throws Exception {  
  Thread t = new Thread(new Runnable() {		
    public void run() {
	  try {
		  lockLocation = getLockLocation(new URI("file:///home/irbull/tmp/locktest"), 1);
		  lockLocation.lock();
	  } catch (IllegalStateException e) {
  		  e.printStackTrace();
  	  } catch (IOException e) {
		  e.printStackTrace();
	  } catch (URISyntaxException e) {
		  e.printStackTrace();
	  }
  }
  });
  t.start();
  t.join();
  System.out.println(getLockLocation(new URI("file:///home/irbull/tmp/locktest"),1).isLocked());
}

private static Location getLockLocation(URI baseLocation, int locationNumber)
		throws IllegalStateException, IOException {
		Location anyLoc = (Location)  Activator.getService(Location.class.getName());
		URI locationURI = URIUtil.append(baseLocation, "" + locationNumber);
		Location location = anyLoc.createLocation(null, URIUtil.toURL(locationURI), false); //$NON-NLS-1$
		location.set(URIUtil.toURL(locationURI),false);
	return location;
}

I didn't see either behaviour specified in the Location class, but maybe I missed it.  This doesn't represent a regression as this never worked before.  However, we should fix this for 3.7.