Re: [Geotools-gt2-users] StyledMapPane memory leak?

[Trevor S. <ts...@ty...>]

On Thu, 2005-04-14 at 05:19, Oliver Meyn wrote:
> I've been working with StyledMapPanes for the last few months but only 
> recently started ramping up the layers in the MapContexts I've been 
> feeding to the Pane.  I've narrowed the "leak" (cumulative memory usage 
> within the jvm) to the setContext method of StyledMapPane, such that 
> when I feed the StyledMapPane a sufficiently large MapContext as follows:
> 
>        MapContext map;
>        /* add some layers */
> 
>        StyledMapPane mapPane = new StyledMapPane();
>        mapPane.setMapContext(this.map);
>        mapPane.setMapContext(null);
>        mapPane = null;
> 
> then I start losing memory.  I've tried running the gc, setting the 
> thread to sleep to wait for gc, both, but no joy.  If I try this test 
> with just an empty DefaultMapContext it works fine, but that's so little 
> memory that my (rather simple) test might not reveal the flaw.
> 
> Looking at the StyledMapPane code it appears that setMapContext really 
> just sets the context of the Renderer in turn, but before I try to get 
> deeper into that I'm hoping someone has some bright ideas as to what's 
> going on and how I can fix it.
> 
I noticed a similar issue a while ago while I was playing with
aerial photos.  In order to prevent my application from running
out of memory, I had to do the following when I removed a coverage
layer:

        if (gridCoverageIds.size() > 0) {
            for (Iterator iter = coverageLayers.iterator();
iter.hasNext();) {
                RenderedLayer element = (RenderedLayer) iter.next();
                map.getRenderer().removeLayer(element);
                element.dispose();
                iter.remove();
            }
            gridCoverageIds.clear();
            // Renderer caches both the original and projected images --
perhaps one reason it's slow
            // without the belowe for loop, we get OutOfMemoryErrors
            RenderedLayer[] renderedLayers =
map.getRenderer().getLayers();
            for (int i = 0; i < renderedLayers.length; i++) {
                if (renderedLayers[i] instanceof RenderedGridCoverage) {
                    map.getRenderer().removeLayer(renderedLayers[i]);
                    renderedLayers[i].dispose();
                }
            }
        }

The dispose() method of RenderedLayer says "really get rid of yourself."

I haven't yet created a JIRA issue for this, but I'll be playing with
it again in the next two days and I'll report my findings (with the
help of a profiler).

-- 
Trevor Stone | Software Engineer | tel 800-554-4434 | fax 303-271-1930 | eMail ts...@ty...
Tyler Technologies | Eagle Division | 14142 Denver West Pkwy Suite 155 | Lakewood, CO 80401 | www.tyler-eagle.com