JAL-1517 update copyright to version 2.8.2

[jalview.git] / src / jalview / structure / StructureSelectionManager.java

diff --git a/src/jalview/structure/StructureSelectionManager.java b/src/jalview/structure/StructureSelectionManager.java
index 7415712..c69b3ad 100644 (file)
--- a/src/jalview/structure/StructureSelectionManager.java
+++ b/src/jalview/structure/StructureSelectionManager.java
@@ -1,6 +1,6 @@
 /*
- * 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.
  * 
@@ -14,6 +14,7 @@
  * 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/>.
+ * The Jalview Authors are detailed in the 'AUTHORS' file.
  */
 package jalview.structure;
 
@@ -53,13 +54,25 @@ public class StructureSelectionManager
   }
 
   Hashtable mappingData = new Hashtable();
-
+  private static StructureSelectionManager nullProvider = null;
   public static StructureSelectionManager getStructureSelectionManager(
           StructureSelectionManagerProvider context)
   {
-    if (context==null)
-    {
-      throw new Error("Implementation error. Structure selection manager's context is 'null'", new NullPointerException("SSM context is null"));
+    if (context==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 +81,13 @@ 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;
   }