X-Git-Url: http://source.jalview.org/gitweb/?a=blobdiff_plain;ds=sidebyside;f=src%2Fjalview%2Fstructure%2FStructureSelectionManager.java;h=c0c559a6a3be4bf817221502a2a680cf54e761cd;hb=1f491c8c9e66b3accb8bb9eae78c7d9caa63c1ac;hp=741571210680f2c4b334d23553db31fd2f860892;hpb=7ce72ca7fadf35a249427ecb836b22abb04ab653;p=jalview.git

diff --git a/src/jalview/structure/StructureSelectionManager.java b/src/jalview/structure/StructureSelectionManager.java
index 7415712..c0c559a 100644
--- a/src/jalview/structure/StructureSelectionManager.java
+++ b/src/jalview/structure/StructureSelectionManager.java
@@ -1,19 +1,22 @@
 /*
- * Jalview - A Sequence Alignment Editor and Viewer (Version 2.8)
- * Copyright (C) 2012 J Procter, AM Waterhouse, LM Lui, J Engelhardt, G Barton, M Clamp, S Searle
+ * Jalview - A Sequence Alignment Editor and Viewer (Version 2.8.2)
+ * Copyright (C) 2014 The Jalview Authors
  * 
  * This file is part of Jalview.
  * 
  * Jalview is free software: you can redistribute it and/or
  * modify it under the terms of the GNU General Public License 
- * as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
+ * as published by the Free Software Foundation, either version 3
+ * of the License, or (at your option) any later version.
  *  
  * Jalview is distributed in the hope that it will be useful, but 
  * WITHOUT ANY WARRANTY; without even the implied warranty 
  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR 
  * PURPOSE.  See the GNU General Public License for more details.
  * 
- * You should have received a copy of the GNU General Public License along with Jalview.  If not, see <http://www.gnu.org/licenses/>.
+ * You should have received a copy of the GNU General Public License
+ * along with Jalview.  If not, see <http://www.gnu.org/licenses/>.
+ * The Jalview Authors are detailed in the 'AUTHORS' file.
  */
 package jalview.structure;
 
@@ -54,12 +57,27 @@ public class StructureSelectionManager
 
   Hashtable mappingData = new Hashtable();
 
+  private static StructureSelectionManager nullProvider = null;
+
   public static StructureSelectionManager getStructureSelectionManager(
           StructureSelectionManagerProvider context)
   {
-    if (context==null)
+    if (context == null)
     {
-      throw new Error("Implementation error. Structure selection manager's context is 'null'", new NullPointerException("SSM context is null"));
+      if (nullProvider == null)
+      {
+        if (instances != null)
+        {
+          throw new Error(
+                  "Implementation error. Structure selection manager's context is 'null'",
+                  new NullPointerException("SSM context is null"));
+        }
+        else
+        {
+          nullProvider = new StructureSelectionManager();
+        }
+        return nullProvider;
+      }
     }
     if (instances == null)
     {
@@ -68,7 +86,15 @@ public class StructureSelectionManager
     StructureSelectionManager instance = instances.get(context);
     if (instance == null)
     {
-      instances.put(context, instance = new StructureSelectionManager());
+      if (nullProvider != null)
+      {
+        instance = nullProvider;
+      }
+      else
+      {
+        instance = new StructureSelectionManager();
+      }
+      instances.put(context, instance);
     }
     return instance;
   }