UIService: Do *not* conflate the 'initialized' and 'disposed' flags

Earlier, this developer tried to be smart (failing) and reuse the
'initialized' flag to indicate whether to show the user interface
or not. However, that flag did not indicate whether the initialize()
method was run yet, but whether the service's lazy initialization was
already performed or not.

Let's just have a separate flag to indicate whether the context was
disposed or not.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

src/main/java/org/scijava/ui/DefaultUIService.java

@@ -134,6 +134,9 @@ public final class DefaultUIService extends AbstractService implements
 	/** Whether lazy initialization is complete. */
 	private boolean initialized;
 
+	/** Whether the service was disposed */
+	private boolean disposed;
+
 	/** The default user interface to use, if one is not explicitly specified. */
 	private UserInterface defaultUI;
 
@@ -154,7 +157,7 @@ public void addUI(final String name, final UserInterface ui) {
 
 	@Override
 	public void showUI() {
-		if (!initialized) return;
+		if (disposed) return;
 		final UserInterface ui = getDefaultUI();
 		if (ui == null) {
 			throw new IllegalStateException("No UIs available.");
@@ -358,7 +361,7 @@ public synchronized void dispose() {
 		for (int i = uis.size() - 1; i >= 0; i--) {
 			uis.get(i).dispose();
 		}
-		initialized = false;
+		disposed = true;
 	}
 
 	// -- Event handlers --