JAL-1645 Version-Rel Version 2.9 Year-Rel 2015 Licensing glob
[jalview.git] / src / jalview / commands / EditCommand.java
index d9f51e0..1cd6fcc 100644 (file)
-/*\r
- * Jalview - A Sequence Alignment Editor and Viewer\r
- * Copyright (C) 2006 AM Waterhouse, J Procter, G Barton, M Clamp, S Searle\r
- *\r
- * This program is free software; you can redistribute it and/or\r
- * modify it under the terms of the GNU General Public License\r
- * as published by the Free Software Foundation; either version 2\r
- * of the License, or (at your option) any later version.\r
- *\r
- * This program is distributed in the hope that it will be useful,\r
- * but WITHOUT ANY WARRANTY; without even the implied warranty of\r
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\r
- * GNU General Public License for more details.\r
- *\r
- * You should have received a copy of the GNU General Public License\r
- * along with this program; if not, write to the Free Software\r
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA\r
- */\r
-package jalview.commands;\r
-\r
-import jalview.datamodel.*;\r
-\r
-import java.util.Hashtable;\r
-\r
-/**\r
- *\r
- * <p>Title: EditCommmand</p>\r
- *\r
- * <p>Description: Essential information for performing\r
- * undo and redo for cut/paste insert/delete gap\r
- * which can be stored in the HistoryList </p>\r
- *\r
- * <p>Copyright: Copyright (c) 2006</p>\r
- *\r
- * <p>Company: Dundee University</p>\r
- *\r
- * @author not attributable\r
- * @version 1.0\r
- */\r
-public class EditCommand implements CommandI\r
-{\r
-  public static final int INSERT_GAP = 0;\r
-  public static final int DELETE_GAP = 1;\r
-  public static final int CUT = 2;\r
-  public static final int PASTE = 3;\r
-\r
-  Edit[] edits;\r
-\r
-  String description;\r
-\r
-  public EditCommand()\r
-  {}\r
-\r
-  public EditCommand(String description)\r
-  {\r
-    this.description = description;\r
-  }\r
-\r
-  public EditCommand( String description,\r
-                      int command,\r
-                      SequenceI[] seqs,\r
-                      int position,\r
-                      int number,\r
-                      AlignmentI al)\r
-   {\r
-     this.description = description;\r
-     if ( command==CUT || command==PASTE)\r
-     {\r
-       edits = new Edit[]{new Edit(command, seqs, position, number, al)};\r
-     }\r
-\r
-     performEdit(0);\r
-  }\r
-\r
-\r
-  final public String getDescription()\r
-  {\r
-    return description;\r
-  }\r
-\r
-  public int getSize()\r
-  {\r
-    return edits==null?0:edits.length;\r
-  }\r
-\r
-  final public AlignmentI getAlignment()\r
-  {\r
-    return edits[0].al;\r
-  }\r
-\r
-\r
-  final public void appendEdit(int command,\r
-                         SequenceI[] seqs,\r
-                         int position,\r
-                         int number,\r
-                         AlignmentI al,\r
-                         boolean performEdit)\r
-  {\r
-    Edit edit = new Edit(command, seqs, position, number, al.getGapCharacter());\r
-    if(al.getHeight()==seqs.length)\r
-    {\r
-      edit.al = al;\r
-      edit.fullAlignmentHeight = true;\r
-    }\r
-\r
-    if (edits != null)\r
-    {\r
-      Edit[] temp = new Edit[edits.length + 1];\r
-      System.arraycopy(edits, 0, temp, 0, edits.length);\r
-      edits = temp;\r
-      edits[edits.length - 1] = edit;\r
-    }\r
-    else\r
-      edits = new Edit[] {  edit  };\r
-\r
-    if (performEdit)\r
-      performEdit(edits.length - 1);\r
-  }\r
-\r
-  final void performEdit(int commandIndex)\r
-  {\r
-    int eSize = edits.length;\r
-    for (int e = commandIndex; e < eSize; e++)\r
-    {\r
-      if (edits[e].command==INSERT_GAP)\r
-      {\r
-        insertGap(edits[e]);\r
-      }\r
-      else if (edits[e].command==DELETE_GAP)\r
-      {\r
-        deleteGap(edits[e]);\r
-      }\r
-      else if(edits[e].command==CUT)\r
-      {\r
-        cut(edits[e]);\r
-      }\r
-      else if(edits[e].command==PASTE)\r
-      {\r
-        paste(edits[e]);\r
-      }\r
-    }\r
-  }\r
-\r
-  final public void doCommand()\r
-  {\r
-    performEdit(0);\r
-  }\r
-\r
-  final public void undoCommand()\r
-  {\r
-    int e = 0, eSize = edits.length;\r
-    for (e = eSize-1; e > -1; e--)\r
-    {\r
-      if (edits[e].command==INSERT_GAP)\r
-      {\r
-        deleteGap(edits[e]);\r
-      }\r
-      else if (edits[e].command==DELETE_GAP)\r
-      {\r
-        insertGap(edits[e]);\r
-      }\r
-      else if (edits[e].command==CUT)\r
-      {\r
-        paste(edits[e]);\r
-      }\r
-      else if (edits[e].command==PASTE)\r
-      {\r
-        cut(edits[e]);\r
-      }\r
-    }\r
-  }\r
-\r
-  final void insertGap(Edit command)\r
-  {\r
-    for(int s=0; s<command.seqs.length; s++)\r
-    {\r
-        command.seqs[s].insertCharAt(command.position,\r
-                                     command.number,\r
-                                     command.gapChar);\r
-    }\r
-\r
-    adjustAnnotations(command, true);\r
-  }\r
-\r
-  final void deleteGap(Edit command)\r
-  {\r
-    for (int s = 0; s < command.seqs.length; s++)\r
-    {\r
-      command.seqs[s].deleteChars(command.position, command.position+command.number);\r
-    }\r
-\r
-    adjustAnnotations(command, false);\r
-  }\r
-\r
-  void cut(Edit command)\r
-  {\r
-    command.string = new char [command.seqs.length][];\r
-\r
-    for(int i=0; i<command.seqs.length; i++)\r
-    {\r
-      if(command.seqs[i].getLength()>command.position)\r
-      {\r
-        command.string[i] = command.seqs[i].getSequence(command.position,\r
-            command.position + command.number);\r
-\r
-        if(command.seqs[i].getDatasetSequence()!=null\r
-        || command.seqs[i].getSequenceFeatures()!=null)\r
-        {\r
-          for (int s = command.position; s < command.position + command.number; s++)\r
-          {\r
-            if (jalview.schemes.ResidueProperties\r
-                .aaIndex[command.seqs[i].getCharAt(s)] != 23)\r
-            {\r
-              adjustFeatures(command, i,\r
-                             command.seqs[i].findPosition(command.position),\r
-                             command.seqs[i].findPosition(command.position +\r
-                                                          command.number),\r
-                             false);\r
-              break;\r
-            }\r
-          }\r
-        }\r
-        command.seqs[i].deleteChars(command.position,\r
-                                    command.position + command.number);\r
-      }\r
-\r
-      if(command.seqs[i].getLength()<1)\r
-      {\r
-        command.al.deleteSequence(command.seqs[i]);\r
-      }\r
-    }\r
-\r
-    adjustAnnotations(command, false);\r
-  }\r
-\r
-  void paste(Edit command)\r
-  {\r
-    StringBuffer tmp;\r
-    boolean newDSNeeded;\r
-    int start=0, end=0;\r
-\r
-    for(int i=0; i<command.seqs.length; i++)\r
-    {\r
-      newDSNeeded = false;\r
-      if(command.seqs[i].getLength()<1)\r
-      {\r
-        // ie this sequence was deleted, we need to\r
-        // read it to the alignment\r
-        if (command.alIndex[i] < command.al.getHeight())\r
-          command.al.getSequences().insertElementAt(command.seqs[i],\r
-              command.alIndex[i]);\r
-        else\r
-          command.al.addSequence(command.seqs[i]);\r
-      }\r
-      tmp = new StringBuffer();\r
-      tmp.append(command.seqs[i].getSequence());\r
-\r
-      if(command.string!=null && command.string[i]!=null)\r
-      {\r
-        if(command.position>=tmp.length())\r
-        {\r
-          //This occurs if padding is on, and residues\r
-          //are removed from end of alignment\r
-          int length = command.position-tmp.length();\r
-          while (length > 0)\r
-          {\r
-            tmp.append(command.gapChar);\r
-            length--;\r
-          }\r
-        }\r
-        tmp.insert(command.position, command.string[i]);\r
-\r
-        for (int s = 0; s < command.string[i].length; s++)\r
-        {\r
-          if (jalview.schemes.ResidueProperties.aaIndex[command.string[i][s]] != 23)\r
-          {\r
-            newDSNeeded = true;\r
-            start = command.seqs[i].findPosition(command.position);\r
-            end = command.seqs[i].findPosition(command.position+command.number);\r
-            break;\r
-          }\r
-        }\r
-        command.string[i] = null;\r
-      }\r
-\r
-\r
-      command.seqs[i].setSequence(tmp.toString());\r
-\r
-      if(newDSNeeded)\r
-      {\r
-        if (command.seqs[i].getDatasetSequence() != null)\r
-        {\r
-          Sequence ds = new Sequence(command.seqs[i].getName(),\r
-                                     jalview.analysis.AlignSeq.extractGaps(\r
-                                         jalview.util.Comparison.GapChars,\r
-                                         command.seqs[i].getSequenceAsString()\r
-                                     ),\r
-                                     command.seqs[i].getStart(),\r
-                                     command.seqs[i].getEnd());\r
-          ds.setDescription(command.seqs[i].getDescription());\r
-          command.seqs[i].setDatasetSequence(ds);\r
-        }\r
-\r
-        adjustFeatures(command, i, start, end, true);\r
-      }\r
-    }\r
-\r
-\r
-    adjustAnnotations(command, true);\r
-\r
-    command.string = null;\r
-  }\r
-\r
-\r
-  final void adjustAnnotations(Edit command, boolean insert)\r
-  {\r
-\r
-    AlignmentAnnotation [] annotations = null;\r
-\r
-    if (command.fullAlignmentHeight)\r
-    {\r
-      annotations = command.al.getAlignmentAnnotation();\r
-    }\r
-    else\r
-    {\r
-      int aSize = 0;\r
-      AlignmentAnnotation [] tmp;\r
-      for(int s=0; s<command.seqs.length; s++)\r
-      {\r
-        if(command.seqs[s].getAnnotation()==null)\r
-          continue;\r
-\r
-        if (aSize == 0)\r
-            annotations = command.seqs[s].getAnnotation();\r
-        else\r
-        {\r
-          tmp = new AlignmentAnnotation\r
-              [aSize + command.seqs[s].getAnnotation().length];\r
-\r
-          System.arraycopy(annotations,0,tmp,0,aSize);\r
-\r
-          System.arraycopy(command.seqs[s].getAnnotation(),\r
-              0,tmp,aSize,command.seqs[s].getAnnotation().length);\r
-\r
-          annotations = tmp;\r
-        }\r
-\r
-\r
-        aSize = annotations.length;\r
-      }\r
-    }\r
-\r
-    if(annotations==null)\r
-      return;\r
-\r
-\r
-      if(!insert)\r
-        command.deletedAnnotations = new Hashtable();\r
-\r
-      int aSize;\r
-      Annotation [] temp;\r
-      for (int a = 0; a < annotations.length; a++)\r
-      {\r
-        if(annotations[a].autoCalculated)\r
-        {\r
-          continue;\r
-        }\r
-\r
-        int tSize = 0;\r
-\r
-        aSize = annotations[a].annotations.length;\r
-        if(insert)\r
-          temp = new Annotation[aSize + command.number];\r
-        else\r
-        {\r
-          if(command.position<aSize)\r
-          {\r
-            if(command.position+command.number>aSize)\r
-              tSize = aSize;\r
-            else\r
-             {\r
-                tSize = aSize - command.number + command.position;\r
-             }\r
-          }\r
-          else\r
-            tSize = aSize;\r
-\r
-          if(tSize<0)\r
-          {\r
-            tSize = aSize;\r
-          }\r
-          temp = new Annotation[tSize];\r
-\r
-        }\r
-\r
-        if(insert)\r
-        {\r
-          if(command.position < annotations[a].annotations.length)\r
-          {\r
-            System.arraycopy(annotations[a].annotations,\r
-                             0, temp, 0, command.position);\r
-\r
-            if (command.deletedAnnotations != null\r
-                &&\r
-                command.deletedAnnotations.containsKey(annotations[a].annotationId))\r
-            {\r
-              Annotation[] restore = (Annotation[])\r
-                  command.deletedAnnotations.get(annotations[a].annotationId);\r
-\r
-              System.arraycopy(restore,\r
-                               0,\r
-                               temp,\r
-                               command.position,\r
-                               command.number);\r
-\r
-            }\r
-\r
-            System.arraycopy(annotations[a].annotations,\r
-                             command.position, temp,\r
-                             command.position + command.number,\r
-                             aSize - command.position);\r
-          }\r
-          else\r
-          {\r
-            if (command.deletedAnnotations != null\r
-                           &&\r
-                           command.deletedAnnotations.containsKey(annotations[a].annotationId))\r
-            {\r
-              Annotation[] restore = (Annotation[])\r
-                  command.deletedAnnotations.get(annotations[a].annotationId);\r
-\r
-              temp = new Annotation[annotations[a].annotations.length+\r
-                  restore.length];\r
-              System.arraycopy(annotations[a].annotations,\r
-                               0,temp,0,\r
-                               annotations[a].annotations.length);\r
-              System.arraycopy(restore,0,temp,annotations[a].annotations.length,restore.length);\r
-            }\r
-            else\r
-              temp = annotations[a].annotations;\r
-          }\r
-        }\r
-        else\r
-        {\r
-          if(tSize!=aSize || command.position<2)\r
-          {\r
-            System.arraycopy(annotations[a].annotations,\r
-                             0, temp, 0, command.position);\r
-\r
-            Annotation[] deleted = new Annotation[command.number];\r
-            System.arraycopy(annotations[a].annotations,\r
-                             command.position, deleted, 0, command.number);\r
-\r
-            command.deletedAnnotations.put(annotations[a].annotationId,\r
-                                           deleted);\r
-\r
-            System.arraycopy(annotations[a].annotations,\r
-                             command.position + command.number,\r
-                             temp, command.position,\r
-                             aSize - command.position - command.number);\r
-          }\r
-          else\r
-          {\r
-            int dSize = aSize - command.position;\r
-\r
-            if(dSize>0)\r
-            {\r
-              Annotation[] deleted = new Annotation[command.number];\r
-              System.arraycopy(annotations[a].annotations,\r
-                               command.position, deleted, 0, dSize);\r
-\r
-              command.deletedAnnotations.put(annotations[a].annotationId,\r
-                                             deleted);\r
-\r
-              tSize = Math.min(annotations[a].annotations.length, command.position);\r
-              temp = new Annotation[tSize];\r
-              System.arraycopy(annotations[a].annotations,\r
-                  0, temp, 0, tSize);\r
-            }\r
-            else\r
-              temp = annotations[a].annotations;\r
-          }\r
-        }\r
-\r
-        annotations[a].annotations = temp;\r
-     }\r
-  }\r
-\r
-  final void adjustFeatures(Edit command, int index, int i, int j, boolean insert)\r
-  {\r
-    SequenceI seq = command.seqs[index];\r
-    SequenceI sequence = seq.getDatasetSequence();\r
-    if(sequence==null)\r
-      sequence = seq;\r
-\r
-    if(insert)\r
-    {\r
-      if (command.editedFeatures != null\r
-          && command.editedFeatures.containsKey(seq))\r
-        sequence.setSequenceFeatures(\r
-            (SequenceFeature[]) command.editedFeatures.get(seq)\r
-            );\r
-\r
-      return;\r
-    }\r
-\r
-\r
-    SequenceFeature [] sf = sequence.getSequenceFeatures();\r
-\r
-\r
-    if(sf==null)\r
-    {\r
-      return;\r
-    }\r
-\r
-    SequenceFeature [] oldsf = new SequenceFeature[sf.length];\r
-\r
-    int cSize = j - i;\r
-\r
-    for (int s = 0; s < sf.length; s++)\r
-    {\r
-      SequenceFeature copy = new SequenceFeature(sf[s]);\r
-\r
-      oldsf[s] = copy;\r
-\r
-      if (sf[s].getEnd() < i)\r
-        continue;\r
-\r
-      if (sf[s].getBegin() > j)\r
-      {\r
-        sf[s].setBegin(copy.getBegin() - cSize);\r
-        sf[s].setEnd(copy.getEnd() - cSize);\r
-        continue;\r
-      }\r
-\r
-      if (sf[s].getBegin() >= i)\r
-        sf[s].setBegin(i);\r
-\r
-      if (sf[s].getEnd() < j)\r
-        sf[s].setEnd(j - 1);\r
-\r
-      sf[s].setEnd(sf[s].getEnd() - (cSize));\r
-\r
-      if (sf[s].getBegin() > sf[s].getEnd())\r
-        sequence.deleteFeature(sf[s]);\r
-    }\r
-\r
-    if (command.editedFeatures == null)\r
-      command.editedFeatures = new Hashtable();\r
-\r
-    command.editedFeatures.put(seq, oldsf);\r
-\r
-  }\r
-\r
-\r
-  class Edit\r
-  {\r
-    boolean fullAlignmentHeight = false;\r
-    Hashtable deletedAnnotations;\r
-    Hashtable editedFeatures;\r
-    AlignmentI al;\r
-    int command;\r
-    char [][] string;\r
-    SequenceI[] seqs;\r
-    int [] alIndex;\r
-    int position, number;\r
-    char gapChar;\r
-\r
-    Edit(int command,\r
-         SequenceI[] seqs,\r
-         int position,\r
-         int number,\r
-         char gapChar)\r
-    {\r
-      this.command = command;\r
-      this.seqs = seqs;\r
-      this.position = position;\r
-      this.number = number;\r
-      this.gapChar = gapChar;\r
-    }\r
-\r
-\r
-    Edit(int command,\r
-         SequenceI[] seqs,\r
-         int position,\r
-         int number,\r
-         AlignmentI al)\r
-    {\r
-      this.gapChar = al.getGapCharacter();\r
-      this.command = command;\r
-      this.seqs = seqs;\r
-      this.position = position;\r
-      this.number = number;\r
-      this.al = al;\r
-\r
-      alIndex = new int[seqs.length];\r
-      for(int i=0; i<seqs.length; i++)\r
-      {\r
-        alIndex[i] = al.findIndex(seqs[i]);\r
-      }\r
-\r
-      fullAlignmentHeight = (al.getHeight()==seqs.length);\r
-    }\r
-  }\r
-\r
-}\r
+/*
+ * Jalview - A Sequence Alignment Editor and Viewer (Version 2.9)
+ * Copyright (C) 2015 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.
+ *  
+ * 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/>.
+ * The Jalview Authors are detailed in the 'AUTHORS' file.
+ */
+package jalview.commands;
+
+import jalview.datamodel.AlignmentAnnotation;
+import jalview.datamodel.AlignmentI;
+import jalview.datamodel.Annotation;
+import jalview.datamodel.Sequence;
+import jalview.datamodel.SequenceFeature;
+import jalview.datamodel.SequenceI;
+import jalview.util.ReverseListIterator;
+import jalview.util.StringUtils;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Hashtable;
+import java.util.Iterator;
+import java.util.List;
+import java.util.ListIterator;
+import java.util.Map;
+
+/**
+ * 
+ * <p>
+ * Title: EditCommmand
+ * </p>
+ * 
+ * <p>
+ * Description: Essential information for performing undo and redo for cut/paste
+ * insert/delete gap which can be stored in the HistoryList
+ * </p>
+ * 
+ * <p>
+ * Copyright: Copyright (c) 2006
+ * </p>
+ * 
+ * <p>
+ * Company: Dundee University
+ * </p>
+ * 
+ * @author not attributable
+ * @version 1.0
+ */
+public class EditCommand implements CommandI
+{
+  public enum Action
+  {
+    INSERT_GAP
+    {
+      @Override
+      public Action getUndoAction()
+      {
+        return DELETE_GAP;
+      }
+    },
+    DELETE_GAP
+    {
+      @Override
+      public Action getUndoAction()
+      {
+        return INSERT_GAP;
+      }
+    },
+    CUT
+    {
+      @Override
+      public Action getUndoAction()
+      {
+        return PASTE;
+      }
+    },
+    PASTE
+    {
+      @Override
+      public Action getUndoAction()
+      {
+        return CUT;
+      }
+    },
+    REPLACE
+    {
+      @Override
+      public Action getUndoAction()
+      {
+        return REPLACE;
+      }
+    },
+    INSERT_NUC
+    {
+      @Override
+      public Action getUndoAction()
+      {
+        return null;
+      }
+    };
+    public abstract Action getUndoAction();
+  };
+
+  private List<Edit> edits = new ArrayList<Edit>();
+
+  String description;
+
+  public EditCommand()
+  {
+  }
+
+  public EditCommand(String description)
+  {
+    this.description = description;
+  }
+
+  public EditCommand(String description, Action command, SequenceI[] seqs,
+          int position, int number, AlignmentI al)
+  {
+    this.description = description;
+    if (command == Action.CUT || command == Action.PASTE)
+    {
+      setEdit(new Edit(command, seqs, position, number, al));
+    }
+
+    performEdit(0, null);
+  }
+
+  public EditCommand(String description, Action command, String replace,
+          SequenceI[] seqs, int position, int number, AlignmentI al)
+  {
+    this.description = description;
+    if (command == Action.REPLACE)
+    {
+      setEdit(new Edit(command, seqs, position, number, al, replace));
+    }
+
+    performEdit(0, null);
+  }
+
+  /**
+   * Set the list of edits to the specified item (only).
+   * 
+   * @param e
+   */
+  protected void setEdit(Edit e)
+  {
+    edits.clear();
+    edits.add(e);
+  }
+
+  /**
+   * Add the given edit command to the stored list of commands. If simply
+   * expanding the range of the last command added, then modify it instead of
+   * adding a new command.
+   * 
+   * @param e
+   */
+  public void addEdit(Edit e)
+  {
+    if (!expandEdit(edits, e))
+    {
+      edits.add(e);
+    }
+  }
+
+  /**
+   * Returns true if the new edit is incorporated by updating (expanding the
+   * range of) the last edit on the list, else false. We can 'expand' the last
+   * edit if the new one is the same action, on the same sequences, and acts on
+   * a contiguous range. This is the case where a mouse drag generates a series
+   * of contiguous gap insertions or deletions.
+   * 
+   * @param edits
+   * @param e
+   * @return
+   */
+  protected static boolean expandEdit(List<Edit> edits, Edit e)
+  {
+    if (edits == null || edits.isEmpty())
+    {
+      return false;
+    }
+    Edit lastEdit = edits.get(edits.size() - 1);
+    Action action = e.command;
+    if (lastEdit.command != action)
+    {
+      return false;
+    }
+
+    /*
+     * Both commands must act on the same sequences - compare the underlying
+     * dataset sequences, rather than the aligned sequences, which change as
+     * they are edited.
+     */
+    if (lastEdit.seqs.length != e.seqs.length)
+    {
+      return false;
+    }
+    for (int i = 0; i < e.seqs.length; i++)
+    {
+      if (lastEdit.seqs[i].getDatasetSequence() != e.seqs[i]
+              .getDatasetSequence())
+      {
+        return false;
+      }
+    }
+
+    /**
+     * Check a contiguous edit; either
+     * <ul>
+     * <li>a new Insert <n> positions to the right of the last <insert n>, or</li>
+     * <li>a new Delete <n> gaps which is <n> positions to the left of the last
+     * delete.</li>
+     * </ul>
+     */
+    boolean contiguous = (action == Action.INSERT_GAP && e.position == lastEdit.position
+            + lastEdit.number)
+            || (action == Action.DELETE_GAP && e.position + e.number == lastEdit.position);
+    if (contiguous)
+    {
+      /*
+       * We are just expanding the range of the last edit. For delete gap, also
+       * moving the start position left.
+       */
+      lastEdit.number += e.number;
+      lastEdit.seqs = e.seqs;
+      if (action == Action.DELETE_GAP)
+      {
+        lastEdit.position--;
+      }
+      return true;
+    }
+    return false;
+  }
+
+  /**
+   * Clear the list of stored edit commands.
+   * 
+   */
+  protected void clearEdits()
+  {
+    edits.clear();
+  }
+
+  /**
+   * Returns the i'th stored Edit command.
+   * 
+   * @param i
+   * @return
+   */
+  protected Edit getEdit(int i)
+  {
+    if (i >= 0 && i < edits.size())
+    {
+      return edits.get(i);
+    }
+    return null;
+  }
+
+  @Override
+  final public String getDescription()
+  {
+    return description;
+  }
+
+  @Override
+  public int getSize()
+  {
+    return edits.size();
+  }
+
+  /**
+   * Return the alignment for the first edit (or null if no edit).
+   * 
+   * @return
+   */
+  final public AlignmentI getAlignment()
+  {
+    return (edits.isEmpty() ? null : edits.get(0).al);
+  }
+
+  /**
+   * append a new editCommand Note. this shouldn't be called if the edit is an
+   * operation affects more alignment objects than the one referenced in al (for
+   * example, cut or pasting whole sequences). Use the form with an additional
+   * AlignmentI[] views parameter.
+   * 
+   * @param command
+   * @param seqs
+   * @param position
+   * @param number
+   * @param al
+   * @param performEdit
+   */
+  final public void appendEdit(Action command, SequenceI[] seqs,
+          int position, int number, AlignmentI al, boolean performEdit)
+  {
+    appendEdit(command, seqs, position, number, al, performEdit, null);
+  }
+
+  /**
+   * append a new edit command with a set of alignment views that may be
+   * operated on
+   * 
+   * @param command
+   * @param seqs
+   * @param position
+   * @param number
+   * @param al
+   * @param performEdit
+   * @param views
+   */
+  final public void appendEdit(Action command, SequenceI[] seqs,
+          int position, int number, AlignmentI al, boolean performEdit,
+          AlignmentI[] views)
+  {
+    Edit edit = new Edit(command, seqs, position, number,
+            al.getGapCharacter());
+    if (al.getHeight() == seqs.length)
+    {
+      edit.al = al;
+      edit.fullAlignmentHeight = true;
+    }
+
+    addEdit(edit);
+
+    if (performEdit)
+    {
+      performEdit(edit, views);
+    }
+  }
+
+  /**
+   * Overloaded method that accepts an Edit object with additional parameters.
+   * 
+   * @param edit
+   * @param al
+   * @param performEdit
+   * @param views
+   */
+  final public void appendEdit(Edit edit, AlignmentI al,
+          boolean performEdit, AlignmentI[] views)
+  {
+    if (al.getHeight() == edit.seqs.length)
+    {
+      edit.al = al;
+      edit.fullAlignmentHeight = true;
+    }
+
+    addEdit(edit);
+
+    if (performEdit)
+    {
+      performEdit(edit, views);
+    }
+  }
+
+  /**
+   * Execute all the edit commands, starting at the given commandIndex
+   * 
+   * @param commandIndex
+   * @param views
+   */
+  public final void performEdit(int commandIndex, AlignmentI[] views)
+  {
+    ListIterator<Edit> iterator = edits.listIterator(commandIndex);
+    while (iterator.hasNext())
+    {
+      Edit edit = iterator.next();
+      performEdit(edit, views);
+    }
+  }
+
+  /**
+   * Execute one edit command in all the specified alignment views
+   * 
+   * @param edit
+   * @param views
+   */
+  protected static void performEdit(Edit edit, AlignmentI[] views)
+  {
+    switch (edit.command)
+    {
+    case INSERT_GAP:
+      insertGap(edit);
+      break;
+    case DELETE_GAP:
+      deleteGap(edit);
+      break;
+    case CUT:
+      cut(edit, views);
+      break;
+    case PASTE:
+      paste(edit, views);
+      break;
+    case REPLACE:
+      replace(edit);
+      break;
+    case INSERT_NUC:
+      // TODO:add deleteNuc for UNDO
+      // case INSERT_NUC:
+      // insertNuc(edits[e]);
+      break;
+    default:
+      break;
+    }
+  }
+
+  @Override
+  final public void doCommand(AlignmentI[] views)
+  {
+    performEdit(0, views);
+  }
+
+  /**
+   * Undo the stored list of commands, in reverse order.
+   */
+  @Override
+  final public void undoCommand(AlignmentI[] views)
+  {
+    ListIterator<Edit> iterator = edits.listIterator(edits.size());
+    while (iterator.hasPrevious())
+    {
+      Edit e = iterator.previous();
+      switch (e.command)
+      {
+      case INSERT_GAP:
+        deleteGap(e);
+        break;
+      case DELETE_GAP:
+        insertGap(e);
+        break;
+      case CUT:
+        paste(e, views);
+        break;
+      case PASTE:
+        cut(e, views);
+        break;
+      case REPLACE:
+        replace(e);
+        break;
+      case INSERT_NUC:
+        // not implemented
+        break;
+      default:
+        break;
+      }
+    }
+  }
+
+  /**
+   * Insert gap(s) in sequences as specified by the command, and adjust
+   * annotations.
+   * 
+   * @param command
+   */
+  final private static void insertGap(Edit command)
+  {
+
+    for (int s = 0; s < command.seqs.length; s++)
+    {
+      command.seqs[s].insertCharAt(command.position, command.number,
+              command.gapChar);
+      // System.out.println("pos: "+command.position+" number: "+command.number);
+    }
+
+    adjustAnnotations(command, true, false, null);
+  }
+
+  //
+  // final void insertNuc(Edit command)
+  // {
+  //
+  // for (int s = 0; s < command.seqs.length; s++)
+  // {
+  // System.out.println("pos: "+command.position+" number: "+command.number);
+  // command.seqs[s].insertCharAt(command.position, command.number,'A');
+  // }
+  //
+  // adjustAnnotations(command, true, false, null);
+  // }
+
+  /**
+   * Delete gap(s) in sequences as specified by the command, and adjust
+   * annotations.
+   * 
+   * @param command
+   */
+  final static private void deleteGap(Edit command)
+  {
+    for (int s = 0; s < command.seqs.length; s++)
+    {
+      command.seqs[s].deleteChars(command.position, command.position
+              + command.number);
+    }
+
+    adjustAnnotations(command, false, false, null);
+  }
+
+  /**
+   * Carry out a Cut action. The cut characters are saved in case Undo is
+   * requested.
+   * 
+   * @param command
+   * @param views
+   */
+  static void cut(Edit command, AlignmentI[] views)
+  {
+    boolean seqDeleted = false;
+    command.string = new char[command.seqs.length][];
+
+    for (int i = 0; i < command.seqs.length; i++)
+    {
+      final SequenceI sequence = command.seqs[i];
+      if (sequence.getLength() > command.position)
+      {
+        command.string[i] = sequence.getSequence(command.position,
+                command.position + command.number);
+        SequenceI oldds = sequence.getDatasetSequence();
+        if (command.oldds != null && command.oldds[i] != null)
+        {
+          // we are redoing an undone cut.
+          sequence.setDatasetSequence(null);
+        }
+        sequence.deleteChars(command.position, command.position
+                + command.number);
+        if (command.oldds != null && command.oldds[i] != null)
+        {
+          // oldds entry contains the cut dataset sequence.
+          sequence.setDatasetSequence(command.oldds[i]);
+          command.oldds[i] = oldds;
+        }
+        else
+        {
+          // modify the oldds if necessary
+          if (oldds != sequence.getDatasetSequence()
+                  || sequence.getSequenceFeatures() != null)
+          {
+            if (command.oldds == null)
+            {
+              command.oldds = new SequenceI[command.seqs.length];
+            }
+            command.oldds[i] = oldds;
+            adjustFeatures(
+                    command,
+                    i,
+                    sequence.findPosition(command.position),
+                    sequence.findPosition(command.position + command.number),
+                    false);
+          }
+        }
+      }
+
+      if (sequence.getLength() < 1)
+      {
+        command.al.deleteSequence(sequence);
+        seqDeleted = true;
+      }
+    }
+
+    adjustAnnotations(command, false, seqDeleted, views);
+  }
+
+  /**
+   * Perform the given Paste command. This may be to add cut or copied sequences
+   * to an alignment, or to undo a 'Cut' action on a region of the alignment.
+   * 
+   * @param command
+   * @param views
+   */
+  static void paste(Edit command, AlignmentI[] views)
+  {
+    StringBuffer tmp;
+    boolean newDSNeeded;
+    boolean newDSWasNeeded;
+    int newstart, newend;
+    boolean seqWasDeleted = false;
+    int start = 0, end = 0;
+
+    for (int i = 0; i < command.seqs.length; i++)
+    {
+      newDSNeeded = false;
+      newDSWasNeeded = command.oldds != null && command.oldds[i] != null;
+      if (command.seqs[i].getLength() < 1)
+      {
+        // ie this sequence was deleted, we need to
+        // readd it to the alignment
+        if (command.alIndex[i] < command.al.getHeight())
+        {
+          List<SequenceI> sequences;
+          synchronized (sequences = command.al.getSequences())
+          {
+            if (!(command.alIndex[i] < 0))
+            {
+              sequences.add(command.alIndex[i], command.seqs[i]);
+            }
+          }
+        }
+        else
+        {
+          command.al.addSequence(command.seqs[i]);
+        }
+        seqWasDeleted = true;
+      }
+      newstart = command.seqs[i].getStart();
+      newend = command.seqs[i].getEnd();
+
+      tmp = new StringBuffer();
+      tmp.append(command.seqs[i].getSequence());
+      // Undo of a delete does not replace original dataset sequence on to
+      // alignment sequence.
+
+      if (command.string != null && command.string[i] != null)
+      {
+        if (command.position >= tmp.length())
+        {
+          // This occurs if padding is on, and residues
+          // are removed from end of alignment
+          int length = command.position - tmp.length();
+          while (length > 0)
+          {
+            tmp.append(command.gapChar);
+            length--;
+          }
+        }
+        tmp.insert(command.position, command.string[i]);
+        for (int s = 0; s < command.string[i].length; s++)
+        {
+          if (jalview.schemes.ResidueProperties.aaIndex[command.string[i][s]] != 23)
+          {
+            if (!newDSNeeded)
+            {
+              newDSNeeded = true;
+              start = command.seqs[i].findPosition(command.position);
+              end = command.seqs[i].findPosition(command.position
+                      + command.number);
+            }
+            if (command.seqs[i].getStart() == start)
+            {
+              newstart--;
+            }
+            else
+            {
+              newend++;
+            }
+          }
+        }
+        command.string[i] = null;
+      }
+
+      command.seqs[i].setSequence(tmp.toString());
+      command.seqs[i].setStart(newstart);
+      command.seqs[i].setEnd(newend);
+      if (newDSNeeded)
+      {
+        if (command.seqs[i].getDatasetSequence() != null)
+        {
+          SequenceI ds;
+          if (newDSWasNeeded)
+          {
+            ds = command.oldds[i];
+          }
+          else
+          {
+            // make a new DS sequence
+            // use new ds mechanism here
+            ds = new Sequence(command.seqs[i].getName(),
+                    jalview.analysis.AlignSeq.extractGaps(
+                            jalview.util.Comparison.GapChars,
+                            command.seqs[i].getSequenceAsString()),
+                    command.seqs[i].getStart(), command.seqs[i].getEnd());
+            ds.setDescription(command.seqs[i].getDescription());
+          }
+          if (command.oldds == null)
+          {
+            command.oldds = new SequenceI[command.seqs.length];
+          }
+          command.oldds[i] = command.seqs[i].getDatasetSequence();
+          command.seqs[i].setDatasetSequence(ds);
+        }
+        adjustFeatures(command, i, start, end, true);
+      }
+    }
+    adjustAnnotations(command, true, seqWasDeleted, views);
+
+    command.string = null;
+  }
+
+  static void replace(Edit command)
+  {
+    StringBuffer tmp;
+    String oldstring;
+    int start = command.position;
+    int end = command.number;
+    // TODO TUTORIAL - Fix for replacement with different length of sequence (or
+    // whole sequence)
+    // TODO Jalview 2.4 bugfix change to an aggregate command - original
+    // sequence string is cut, new string is pasted in.
+    command.number = start + command.string[0].length;
+    for (int i = 0; i < command.seqs.length; i++)
+    {
+      boolean newDSWasNeeded = command.oldds != null
+              && command.oldds[i] != null;
+
+      /**
+       * cut addHistoryItem(new EditCommand("Cut Sequences", EditCommand.CUT,
+       * cut, sg.getStartRes(), sg.getEndRes()-sg.getStartRes()+1,
+       * viewport.alignment));
+       * 
+       */
+      /**
+       * then addHistoryItem(new EditCommand( "Add sequences",
+       * EditCommand.PASTE, sequences, 0, alignment.getWidth(), alignment) );
+       * 
+       */
+      oldstring = command.seqs[i].getSequenceAsString();
+      tmp = new StringBuffer(oldstring.substring(0, start));
+      tmp.append(command.string[i]);
+      String nogaprep = jalview.analysis.AlignSeq.extractGaps(
+              jalview.util.Comparison.GapChars, new String(
+                      command.string[i]));
+      int ipos = command.seqs[i].findPosition(start)
+              - command.seqs[i].getStart();
+      tmp.append(oldstring.substring(end));
+      command.seqs[i].setSequence(tmp.toString());
+      command.string[i] = oldstring.substring(start, end).toCharArray();
+      String nogapold = jalview.analysis.AlignSeq.extractGaps(
+              jalview.util.Comparison.GapChars, new String(
+                      command.string[i]));
+      if (!nogaprep.toLowerCase().equals(nogapold.toLowerCase()))
+      {
+        if (newDSWasNeeded)
+        {
+          SequenceI oldds = command.seqs[i].getDatasetSequence();
+          command.seqs[i].setDatasetSequence(command.oldds[i]);
+          command.oldds[i] = oldds;
+        }
+        else
+        {
+          if (command.oldds == null)
+          {
+            command.oldds = new SequenceI[command.seqs.length];
+          }
+          command.oldds[i] = command.seqs[i].getDatasetSequence();
+          SequenceI newds = new Sequence(
+                  command.seqs[i].getDatasetSequence());
+          String fullseq, osp = newds.getSequenceAsString();
+          fullseq = osp.substring(0, ipos) + nogaprep
+                  + osp.substring(ipos + nogaprep.length());
+          newds.setSequence(fullseq.toUpperCase());
+          // TODO: JAL-1131 ensure newly created dataset sequence is added to
+          // the set of
+          // dataset sequences associated with the alignment.
+          // TODO: JAL-1131 fix up any annotation associated with new dataset
+          // sequence to ensure that original sequence/annotation relationships
+          // are preserved.
+          command.seqs[i].setDatasetSequence(newds);
+
+        }
+      }
+      tmp = null;
+      oldstring = null;
+    }
+  }
+
+  final static void adjustAnnotations(Edit command, boolean insert,
+          boolean modifyVisibility, AlignmentI[] views)
+  {
+    AlignmentAnnotation[] annotations = null;
+
+    if (modifyVisibility && !insert)
+    {
+      // only occurs if a sequence was added or deleted.
+      command.deletedAnnotationRows = new Hashtable<SequenceI, AlignmentAnnotation[]>();
+    }
+    if (command.fullAlignmentHeight)
+    {
+      annotations = command.al.getAlignmentAnnotation();
+    }
+    else
+    {
+      int aSize = 0;
+      AlignmentAnnotation[] tmp;
+      for (int s = 0; s < command.seqs.length; s++)
+      {
+        if (modifyVisibility)
+        {
+          // Rows are only removed or added to sequence object.
+          if (!insert)
+          {
+            // remove rows
+            tmp = command.seqs[s].getAnnotation();
+            if (tmp != null)
+            {
+              int alen = tmp.length;
+              for (int aa = 0; aa < tmp.length; aa++)
+              {
+                if (!command.al.deleteAnnotation(tmp[aa]))
+                {
+                  // strip out annotation not in the current al (will be put
+                  // back on insert in all views)
+                  tmp[aa] = null;
+                  alen--;
+                }
+              }
+              command.seqs[s].setAlignmentAnnotation(null);
+              if (alen != tmp.length)
+              {
+                // save the non-null annotation references only
+                AlignmentAnnotation[] saved = new AlignmentAnnotation[alen];
+                for (int aa = 0, aapos = 0; aa < tmp.length; aa++)
+                {
+                  if (tmp[aa] != null)
+                  {
+                    saved[aapos++] = tmp[aa];
+                    tmp[aa] = null;
+                  }
+                }
+                tmp = saved;
+                command.deletedAnnotationRows.put(command.seqs[s], saved);
+                // and then remove any annotation in the other views
+                for (int alview = 0; views != null && alview < views.length; alview++)
+                {
+                  if (views[alview] != command.al)
+                  {
+                    AlignmentAnnotation[] toremove = views[alview]
+                            .getAlignmentAnnotation();
+                    if (toremove == null || toremove.length == 0)
+                    {
+                      continue;
+                    }
+                    // remove any alignment annotation on this sequence that's
+                    // on that alignment view.
+                    for (int aa = 0; aa < toremove.length; aa++)
+                    {
+                      if (toremove[aa].sequenceRef == command.seqs[s])
+                      {
+                        views[alview].deleteAnnotation(toremove[aa]);
+                      }
+                    }
+                  }
+                }
+              }
+              else
+              {
+                // save all the annotation
+                command.deletedAnnotationRows.put(command.seqs[s], tmp);
+              }
+            }
+          }
+          else
+          {
+            // recover rows
+            if (command.deletedAnnotationRows != null
+                    && command.deletedAnnotationRows
+                            .containsKey(command.seqs[s]))
+            {
+              AlignmentAnnotation[] revealed = command.deletedAnnotationRows
+                      .get(command.seqs[s]);
+              command.seqs[s].setAlignmentAnnotation(revealed);
+              if (revealed != null)
+              {
+                for (int aa = 0; aa < revealed.length; aa++)
+                {
+                  // iterate through al adding original annotation
+                  command.al.addAnnotation(revealed[aa]);
+                }
+                for (int aa = 0; aa < revealed.length; aa++)
+                {
+                  command.al.setAnnotationIndex(revealed[aa], aa);
+                }
+                // and then duplicate added annotation on every other alignment
+                // view
+                for (int vnum = 0; views != null && vnum < views.length; vnum++)
+                {
+                  if (views[vnum] != command.al)
+                  {
+                    int avwidth = views[vnum].getWidth() + 1;
+                    // duplicate in this view
+                    for (int a = 0; a < revealed.length; a++)
+                    {
+                      AlignmentAnnotation newann = new AlignmentAnnotation(
+                              revealed[a]);
+                      command.seqs[s].addAlignmentAnnotation(newann);
+                      newann.padAnnotation(avwidth);
+                      views[vnum].addAnnotation(newann);
+                      views[vnum].setAnnotationIndex(newann, a);
+                    }
+                  }
+                }
+              }
+            }
+          }
+          continue;
+        }
+
+        if (command.seqs[s].getAnnotation() == null)
+        {
+          continue;
+        }
+
+        if (aSize == 0)
+        {
+          annotations = command.seqs[s].getAnnotation();
+        }
+        else
+        {
+          tmp = new AlignmentAnnotation[aSize
+                  + command.seqs[s].getAnnotation().length];
+
+          System.arraycopy(annotations, 0, tmp, 0, aSize);
+
+          System.arraycopy(command.seqs[s].getAnnotation(), 0, tmp, aSize,
+                  command.seqs[s].getAnnotation().length);
+
+          annotations = tmp;
+        }
+        aSize = annotations.length;
+      }
+    }
+
+    if (annotations == null)
+    {
+      return;
+    }
+
+    if (!insert)
+    {
+      command.deletedAnnotations = new Hashtable<String, Annotation[]>();
+    }
+
+    int aSize;
+    Annotation[] temp;
+    for (int a = 0; a < annotations.length; a++)
+    {
+      if (annotations[a].autoCalculated
+              || annotations[a].annotations == null)
+      {
+        continue;
+      }
+
+      int tSize = 0;
+
+      aSize = annotations[a].annotations.length;
+      if (insert)
+      {
+        temp = new Annotation[aSize + command.number];
+        if (annotations[a].padGaps)
+        {
+          for (int aa = 0; aa < temp.length; aa++)
+          {
+            temp[aa] = new Annotation(command.gapChar + "", null, ' ', 0);
+          }
+        }
+      }
+      else
+      {
+        if (command.position < aSize)
+        {
+          if (command.position + command.number >= aSize)
+          {
+            tSize = aSize;
+          }
+          else
+          {
+            tSize = aSize - command.number;
+          }
+        }
+        else
+        {
+          tSize = aSize;
+        }
+
+        if (tSize < 0)
+        {
+          tSize = aSize;
+        }
+        temp = new Annotation[tSize];
+      }
+
+      if (insert)
+      {
+        if (command.position < annotations[a].annotations.length)
+        {
+          System.arraycopy(annotations[a].annotations, 0, temp, 0,
+                  command.position);
+
+          if (command.deletedAnnotations != null
+                  && command.deletedAnnotations
+                          .containsKey(annotations[a].annotationId))
+          {
+            Annotation[] restore = command.deletedAnnotations
+                    .get(annotations[a].annotationId);
+
+            System.arraycopy(restore, 0, temp, command.position,
+                    command.number);
+
+          }
+
+          System.arraycopy(annotations[a].annotations, command.position,
+                  temp, command.position + command.number, aSize
+                          - command.position);
+        }
+        else
+        {
+          if (command.deletedAnnotations != null
+                  && command.deletedAnnotations
+                          .containsKey(annotations[a].annotationId))
+          {
+            Annotation[] restore = command.deletedAnnotations
+                    .get(annotations[a].annotationId);
+
+            temp = new Annotation[annotations[a].annotations.length
+                    + restore.length];
+            System.arraycopy(annotations[a].annotations, 0, temp, 0,
+                    annotations[a].annotations.length);
+            System.arraycopy(restore, 0, temp,
+                    annotations[a].annotations.length, restore.length);
+          }
+          else
+          {
+            temp = annotations[a].annotations;
+          }
+        }
+      }
+      else
+      {
+        if (tSize != aSize || command.position < 2)
+        {
+          int copylen = Math.min(command.position,
+                  annotations[a].annotations.length);
+          if (copylen > 0)
+          {
+            System.arraycopy(annotations[a].annotations, 0, temp, 0,
+                    copylen); // command.position);
+          }
+
+          Annotation[] deleted = new Annotation[command.number];
+          if (copylen >= command.position)
+          {
+            copylen = Math.min(command.number,
+                    annotations[a].annotations.length - command.position);
+            if (copylen > 0)
+            {
+              System.arraycopy(annotations[a].annotations,
+                      command.position, deleted, 0, copylen); // command.number);
+            }
+          }
+
+          command.deletedAnnotations.put(annotations[a].annotationId,
+                  deleted);
+          if (annotations[a].annotations.length > command.position
+                  + command.number)
+          {
+            System.arraycopy(annotations[a].annotations, command.position
+                    + command.number, temp, command.position,
+                    annotations[a].annotations.length - command.position
+                            - command.number); // aSize
+          }
+        }
+        else
+        {
+          int dSize = aSize - command.position;
+
+          if (dSize > 0)
+          {
+            Annotation[] deleted = new Annotation[command.number];
+            System.arraycopy(annotations[a].annotations, command.position,
+                    deleted, 0, dSize);
+
+            command.deletedAnnotations.put(annotations[a].annotationId,
+                    deleted);
+
+            tSize = Math.min(annotations[a].annotations.length,
+                    command.position);
+            temp = new Annotation[tSize];
+            System.arraycopy(annotations[a].annotations, 0, temp, 0, tSize);
+          }
+          else
+          {
+            temp = annotations[a].annotations;
+          }
+        }
+      }
+
+      annotations[a].annotations = temp;
+    }
+  }
+
+  final static void adjustFeatures(Edit command, int index, int i, int j,
+          boolean insert)
+  {
+    SequenceI seq = command.seqs[index];
+    SequenceI sequence = seq.getDatasetSequence();
+    if (sequence == null)
+    {
+      sequence = seq;
+    }
+
+    if (insert)
+    {
+      if (command.editedFeatures != null
+              && command.editedFeatures.containsKey(seq))
+      {
+        sequence.setSequenceFeatures(command.editedFeatures.get(seq));
+      }
+
+      return;
+    }
+
+    SequenceFeature[] sf = sequence.getSequenceFeatures();
+
+    if (sf == null)
+    {
+      return;
+    }
+
+    SequenceFeature[] oldsf = new SequenceFeature[sf.length];
+
+    int cSize = j - i;
+
+    for (int s = 0; s < sf.length; s++)
+    {
+      SequenceFeature copy = new SequenceFeature(sf[s]);
+
+      oldsf[s] = copy;
+
+      if (sf[s].getEnd() < i)
+      {
+        continue;
+      }
+
+      if (sf[s].getBegin() > j)
+      {
+        sf[s].setBegin(copy.getBegin() - cSize);
+        sf[s].setEnd(copy.getEnd() - cSize);
+        continue;
+      }
+
+      if (sf[s].getBegin() >= i)
+      {
+        sf[s].setBegin(i);
+      }
+
+      if (sf[s].getEnd() < j)
+      {
+        sf[s].setEnd(j - 1);
+      }
+
+      sf[s].setEnd(sf[s].getEnd() - (cSize));
+
+      if (sf[s].getBegin() > sf[s].getEnd())
+      {
+        sequence.deleteFeature(sf[s]);
+      }
+    }
+
+    if (command.editedFeatures == null)
+    {
+      command.editedFeatures = new Hashtable<SequenceI, SequenceFeature[]>();
+    }
+
+    command.editedFeatures.put(seq, oldsf);
+
+  }
+
+  /**
+   * Returns the list of edit commands wrapped by this object.
+   * 
+   * @return
+   */
+  public List<Edit> getEdits()
+  {
+    return this.edits;
+  }
+
+  /**
+   * Returns a map whose keys are the dataset sequences, and values their
+   * aligned sequences before the command edit list was applied. The aligned
+   * sequences are copies, which may be updated without affecting the originals.
+   * 
+   * The command holds references to the aligned sequences (after editing). If
+   * the command is an 'undo',then the prior state is simply the aligned state.
+   * Otherwise, we have to derive the prior state by working backwards through
+   * the edit list to infer the aligned sequences before editing.
+   * 
+   * Note: an alternative solution would be to cache the 'before' state of each
+   * edit, but this would be expensive in space in the common case that the
+   * original is never needed (edits are not mirrored).
+   * 
+   * @return
+   * @throws IllegalStateException
+   *           on detecting an edit command of a type that can't be unwound
+   */
+  public Map<SequenceI, SequenceI> priorState(boolean forUndo)
+  {
+    Map<SequenceI, SequenceI> result = new HashMap<SequenceI, SequenceI>();
+    if (getEdits() == null)
+    {
+      return result;
+    }
+    if (forUndo)
+    {
+      for (Edit e : getEdits())
+      {
+        for (SequenceI seq : e.getSequences())
+        {
+          SequenceI ds = seq.getDatasetSequence();
+          SequenceI preEdit = result.get(ds);
+          if (preEdit == null)
+          {
+            preEdit = new Sequence("", seq.getSequenceAsString());
+            preEdit.setDatasetSequence(ds);
+            result.put(ds, preEdit);
+          }
+        }
+      }
+      return result;
+    }
+
+    /*
+     * Work backwards through the edit list, deriving the sequences before each
+     * was applied. The final result is the sequence set before any edits.
+     */
+    Iterator<Edit> edits = new ReverseListIterator<Edit>(getEdits());
+    while (edits.hasNext())
+    {
+      Edit oldEdit = edits.next();
+      Action action = oldEdit.getAction();
+      int position = oldEdit.getPosition();
+      int number = oldEdit.getNumber();
+      final char gap = oldEdit.getGapCharacter();
+      for (SequenceI seq : oldEdit.getSequences())
+      {
+        SequenceI ds = seq.getDatasetSequence();
+        SequenceI preEdit = result.get(ds);
+        if (preEdit == null)
+        {
+          preEdit = new Sequence("", seq.getSequenceAsString());
+          preEdit.setDatasetSequence(ds);
+          result.put(ds, preEdit);
+        }
+        /*
+         * 'Undo' this edit action on the sequence (updating the value in the
+         * map).
+         */
+        if (ds != null)
+        {
+          if (action == Action.DELETE_GAP)
+          {
+            preEdit.setSequence(new String(StringUtils.insertCharAt(
+                    preEdit.getSequence(), position, number, gap)));
+          }
+          else if (action == Action.INSERT_GAP)
+          {
+            preEdit.setSequence(new String(StringUtils.deleteChars(
+                    preEdit.getSequence(), position, position + number)));
+          }
+          else
+          {
+            System.err.println("Can't undo edit action " + action);
+            // throw new IllegalStateException("Can't undo edit action " +
+            // action);
+          }
+        }
+      }
+    }
+    return result;
+  }
+
+  public class Edit
+  {
+    public SequenceI[] oldds;
+
+    boolean fullAlignmentHeight = false;
+
+    Hashtable<SequenceI, AlignmentAnnotation[]> deletedAnnotationRows;
+
+    Hashtable<String, Annotation[]> deletedAnnotations;
+
+    Hashtable<SequenceI, SequenceFeature[]> editedFeatures;
+
+    AlignmentI al;
+
+    Action command;
+
+    char[][] string;
+
+    SequenceI[] seqs;
+
+    int[] alIndex;
+
+    int position, number;
+
+    char gapChar;
+
+    public Edit(Action command, SequenceI[] seqs, int position, int number,
+            char gapChar)
+    {
+      this.command = command;
+      this.seqs = seqs;
+      this.position = position;
+      this.number = number;
+      this.gapChar = gapChar;
+    }
+
+    Edit(Action command, SequenceI[] seqs, int position, int number,
+            AlignmentI al)
+    {
+      this.gapChar = al.getGapCharacter();
+      this.command = command;
+      this.seqs = seqs;
+      this.position = position;
+      this.number = number;
+      this.al = al;
+
+      alIndex = new int[seqs.length];
+      for (int i = 0; i < seqs.length; i++)
+      {
+        alIndex[i] = al.findIndex(seqs[i]);
+      }
+
+      fullAlignmentHeight = (al.getHeight() == seqs.length);
+    }
+
+    Edit(Action command, SequenceI[] seqs, int position, int number,
+            AlignmentI al, String replace)
+    {
+      this.command = command;
+      this.seqs = seqs;
+      this.position = position;
+      this.number = number;
+      this.al = al;
+      this.gapChar = al.getGapCharacter();
+      string = new char[seqs.length][];
+      for (int i = 0; i < seqs.length; i++)
+      {
+        string[i] = replace.toCharArray();
+      }
+
+      fullAlignmentHeight = (al.getHeight() == seqs.length);
+    }
+
+    public SequenceI[] getSequences()
+    {
+      return seqs;
+    }
+
+    public int getPosition()
+    {
+      return position;
+    }
+
+    public Action getAction()
+    {
+      return command;
+    }
+
+    public int getNumber()
+    {
+      return number;
+    }
+
+    public char getGapCharacter()
+    {
+      return gapChar;
+    }
+  }
+
+  /**
+   * Returns an iterator over the list of edit commands which traverses the list
+   * either forwards or backwards.
+   * 
+   * @param forwards
+   * @return
+   */
+  public Iterator<Edit> getEditIterator(boolean forwards)
+  {
+    if (forwards)
+    {
+      return getEdits().iterator();
+    }
+    else
+    {
+      return new ReverseListIterator<Edit>(getEdits());
+    }
+  }
+}