X-Git-Url: http://gitweb.fperrin.net/?p=GpsPrune.git;a=blobdiff_plain;f=tim%2Fprune%2Fundo%2FUndoStack.java;fp=tim%2Fprune%2Fundo%2FUndoStack.java;h=d3e85e02e3f5d078eb49ac612e084528d34eae1c;hp=bca92b11119114e930bd28a95785e2cc1cff2130;hb=0a2480df5845e2d7190dfdec9b2653b1609e853d;hpb=2154b1969ac2995cca46546f217f53c066b0b749

diff --git a/tim/prune/undo/UndoStack.java b/tim/prune/undo/UndoStack.java
index bca92b1..d3e85e0 100644
--- 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;
+	}
 }