GUIMultiModelHandler: Inhibit creation of WaitParseThread during GUI startup

Previously, during the constructor of GUIMultiModelHandler, a WaitParseThread
was created. If the startup of the other plugins takes longer than the configured delay
(default = 1s, but can be much shorter via settings), the attempted parse can generate
events that reach other plugins/components that are not yet fully initialised, leading
to NullPointerExceptions, etc.

Now, we inhibit the creation of the WaitParseThread until the startup has
completed.

Fixes #111.

prism/src/userinterface/model/GUIMultiModel.java

@@ -120,6 +120,13 @@ public class GUIMultiModel extends GUIPlugin implements PrismSettingsListener
 		}
 	}
 
+	@Override
+	public void onInitComponentsCompleted()
+	{
+		// forward to multi-model handler
+		handler.onInitComponentsCompleted();
+	}
+
 	public GUIMultiModelHandler getHandler()
 	{
 		return handler;

prism/src/userinterface/model/GUIMultiModelHandler.java

@@ -113,6 +113,9 @@ public class GUIMultiModelHandler extends JPanel implements PrismModelListener
 
 	private Style pepaEditorCommentFast = Style.defaultStyle();
 
+	// flag to indicate whether onInitComponentsCompleted() has already been called
+	private boolean startupCompleted = false;
+
 	// Modification Parse updater
 	private WaitParseThread waiter;
 	private boolean parsing = false;
@@ -142,8 +145,6 @@ public class GUIMultiModelHandler extends JPanel implements PrismModelListener
 		prism = theModel.getPrism();
 		prism.addModelListener(this);
 
-		int parseDelay = theModel.getPrism().getSettings().getInteger(PrismSettings.MODEL_PARSE_DELAY);
-		waiter = new WaitParseThread(parseDelay, this);
 		editor = new GUITextModelEditor("", this);
 		tree = new GUIMultiModelTree(this);
 		splitter = new JSplitPane();
@@ -227,6 +228,14 @@ public class GUIMultiModelHandler extends JPanel implements PrismModelListener
 
 	private synchronized void restartWaitParseThread()
 	{
+		// If the GUIPrism startup has not been completed, as
+		// indicated by the call to onInitComponentsCompleted(),
+		// ignore requests to start the WaitParseThread. This prevents
+		// it from triggering events that are handled by parts of the
+		// GUI that have not been completely initialised.
+		if (!startupCompleted)
+			return;
+
 		if (waiter != null) {
 			waiter.interrupt();
 		}
@@ -236,6 +245,14 @@ public class GUIMultiModelHandler extends JPanel implements PrismModelListener
 		//Funky thread waiting stuff
 	}
 
+	public void onInitComponentsCompleted()
+	{
+		startupCompleted = true;
+
+		// initially, start WaitParseThread
+		restartWaitParseThread();
+	}
+
 	// New model...
 
 	public void newPRISMModel()