Handle empty firstComment of a Note

Resolves #27

Author: kmpoppe

notesolver/src/main/java/org/openstreetmap/josm/plugins/notesolver/NoteSolverPlugin.java

@@ -405,7 +405,7 @@ private List<JMenuItem> mainMenuEntries(Enum<menuTypes> menuType) {
 					returnList.add(
 						createMenuItem(
 							NoteText.noteShortText(note), 
-							note.getFirstComment().toString(),
+							(note.getFirstComment() != null ? note.getFirstComment().toString() : ""),
 							new ActionListener() {
 								@Override
 								public void actionPerformed(ActionEvent ev) {

notesolver/src/main/java/org/openstreetmap/josm/plugins/notesolver/NoteText.java

@@ -1,15 +1,24 @@
 package org.openstreetmap.josm.plugins.notesolver;
 
+import org.openstreetmap.josm.tools.I18n;
 import org.openstreetmap.josm.data.notes.*;
 
 public class NoteText {
 	private static int maxMenuItemLen = 50;
 	public static String noteShortText(Note n) {
-		String firstComment = n.getFirstComment().toString();
-		if (firstComment.length() > maxMenuItemLen) firstComment = firstComment.substring(0, maxMenuItemLen) + "...";
+		String firstComment = "";
+		String firstUser = "";
+		if (n.getFirstComment() != null) {
+			firstUser = n.getFirstComment().getUser().getName().toString();
+			firstComment = n.getFirstComment().toString();
+			if (firstComment.length() > maxMenuItemLen) firstComment = firstComment.substring(0, maxMenuItemLen) + "...";
+		} else {
+			firstUser = I18n.tr("Deleted user");
+			firstComment = I18n.tr("Deleted comment");
+		}
 		String menuItemText =   
 			"* " + Long.toString(n.getId()) + " " +
-			"[" + n.getFirstComment().getUser().getName().toString() + 
+			"[" + firstUser + 
 			": " + firstComment + 
 			"]";
 		return menuItemText;