[udig-dev] Add Layer Wizard Performance

[Emily Gouge <egouge@xxxxxxxxxxxxxxx>]

I noticed if I dragged a layer from the catalog onto the map it was 
added instantly. However if I used the Add Data wizard the layers were 
added immediately, but it would take another 5-10 seconds for the wizard 
to close.
I always found this somewhat annoying, so I decided to see if I could 
find the source of the issue.

I discovered the problem occurs when Tools' enabled states are updated 
after the newly added layers is selected.  Updating each tool (from the 
import data wizard) makes a Display.AsyncExec call for each tool, which 
apparently, when you have 40 or so tools, causes quite a delay.  This 
was not a problem when dragging from the catalog as this code is already 
executed in the display thread.

This can be fixed by wrapping the setEnabled calls in a single Display 
thread so it is only done once.  I accomplished this by updating the 
ToolManager.setEnabled function as shown below (so it is execute once 
for each category of tools).

If this seems reasonable to others I can contribute the change back to 
the uDig master easily enough.

Emily

private void setEnabled( final IMap map, final Collection<? extends 
ToolCategory> categories) {
  if(selectedLayerListener == null)
    selectedLayerListener = new EditManagerListener();

  selectedLayerListener.setCurrentMap(map);

    //One listener is enough. Say NO to listeners hell:)
  if(!map.getEditManager().containsListener(selectedLayerListener))
    map.getEditManager().addListener(selectedLayerListener);

  PlatformGIS.syncInDisplayThread(new Runnable(){
    @Override
    public void run() {
      ILayer selectedLayer = map.getEditManager().getSelectedLayer();
			
      for( ToolCategory cat : categories ) {
        for( ModalItem item : cat ) {
          OpFilter enablesFor = item.getEnablesFor();
          // JG: I don't trust asserts in production code!
          // assert enablesFor instanceof LazyOpFilter;
          if( !(enablesFor instanceof LazyOpFilter) ){
            enablesFor = new LazyOpFilter(item, enablesFor);
          }

          boolean accept = enablesFor.accept(selectedLayer);
          item.setEnabled(accept);
        }
      }
  }});
}