Version 18, July 2015

[GpsPrune.git] / tim / prune / undo / UndoStack.java

diff --git a/tim/prune/undo/UndoStack.java b/tim/prune/undo/UndoStack.java
index bca92b11119114e930bd28a95785e2cc1cff2130..d3e85e02e3f5d078eb49ac612e084528d34eae1c 100644 (file)
--- a/tim/prune/undo/UndoStack.java
+++ b/tim/prune/undo/UndoStack.java
@@ -3,22 +3,60 @@ package tim.prune.undo;
 import java.util.Stack;
 
 /**
- * Stack of undo operations
- * which also remembers how many times it's been cleared
+ * Class to hold an undo operation together with a counter
  */
-public class UndoStack extends Stack<UndoOperation>
+class UndoOpWithState
 {
-       private int _numTimesDeleted = 0;
-
-       /** @return number of times this stack has been deleted */
-       public int getNumTimesDeleted() {
-               return _numTimesDeleted;
+       public UndoOperation _undoOperation = null;
+       public int           _undoCounter = 0;
+       /** Constructor */
+       public UndoOpWithState(UndoOperation inOp, int inCounter)
+       {
+               _undoOperation = inOp;
+               _undoCounter   = inCounter;
        }
+}
+
+/**
+ * Stack of undo operations
+ * which also remembers how many undos have been performed
+ */
+public class UndoStack extends Stack<UndoOpWithState>
+{
+       /** Number of undos (and clears) already performed */
+       private int _numUndos = 0;
 
        @Override
        public void clear()
        {
-               _numTimesDeleted++;
+               _numUndos++;
                super.clear();
        }
+
+       /** Add an undo operation to the stack */
+       public synchronized boolean add(UndoOperation inOp)
+       {
+               return super.add(new UndoOpWithState(inOp, _numUndos));
+       }
+
+       /** Pop the latest operation from the stack */
+       public synchronized UndoOperation popOperation()
+       {
+               _numUndos++;
+               return super.pop()._undoOperation;
+       }
+
+       /** Get the operation at the given index */
+       public UndoOperation getOperationAt(int inIndex)
+       {
+               return super.elementAt(inIndex)._undoOperation;
+       }
+
+       /** @return number of undos */
+       public int getNumUndos()
+       {
+               if (isEmpty()) {return 0;}
+               // Get the number of undos stored by the last operation on the stack
+               return peek()._undoCounter;
+       }
 }