X-Git-Url: http://source.jalview.org/gitweb/?a=blobdiff_plain;f=src%2Fjalview%2Fdatamodel%2FAlignment.java;h=35ee8c4ef9fafc31d5b7c0e39386fa79ee1deae4;hb=3446323f14bb8a2842cb83f74ed3f41c99b62759;hp=fd918fc709fffdf48390fb8a80f70c36d5614799;hpb=4956fb78f7222e84d0d7008a6b91146d6c61d151;p=jalview.git

diff --git a/src/jalview/datamodel/Alignment.java b/src/jalview/datamodel/Alignment.java
index fd918fc..35ee8c4 100755
--- a/src/jalview/datamodel/Alignment.java
+++ b/src/jalview/datamodel/Alignment.java
@@ -226,18 +226,21 @@ public class Alignment implements AlignmentI
   {
     if (dataset != null)
     {
+
       // maintain dataset integrity
-      if (snew.getDatasetSequence() != null)
-      {
-        getDataset().addSequence(snew.getDatasetSequence());
-      }
-      else
+      SequenceI dsseq = snew.getDatasetSequence();
+      if (dsseq == null)
       {
         // derive new sequence
         SequenceI adding = snew.deriveSequence();
-        getDataset().addSequence(adding.getDatasetSequence());
         snew = adding;
+        dsseq = snew.getDatasetSequence();
       }
+      if (getDataset().findIndex(dsseq) == -1)
+      {
+        getDataset().addSequence(dsseq);
+      }
+
     }
     if (sequences == null)
     {
@@ -287,13 +290,23 @@ public class Alignment implements AlignmentI
   }
 
   @Override
-  public void finalize()
+  public void finalize() throws Throwable
   {
     if (getDataset() != null)
     {
       getDataset().removeAlignmentRef();
     }
 
+    nullReferences();
+    super.finalize();
+  }
+
+  /**
+   * Defensively nulls out references in case this object is not garbage
+   * collected
+   */
+  void nullReferences()
+  {
     dataset = null;
     sequences = null;
     groups = null;
@@ -302,14 +315,16 @@ public class Alignment implements AlignmentI
   }
 
   /**
-   * decrement the alignmentRefs counter by one and call finalize if it goes to
-   * zero.
+   * decrement the alignmentRefs counter by one and null references if it goes
+   * to zero.
+   * 
+   * @throws Throwable
    */
-  private void removeAlignmentRef()
+  private void removeAlignmentRef() throws Throwable
   {
     if (--alignmentRefs == 0)
     {
-      finalize();
+      nullReferences();
     }
   }