Added basic undo/redo functionality with a history size of 15.

src/EditSession.java

@@ -0,0 +1,107 @@
+// $Id$
+/*
+ * WorldEdit
+ * Copyright (C) 2010 sk89q <http://www.sk89q.com>
+ *
+ * This program 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.
+ *
+ * This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+import java.util.Map;
+import java.util.HashMap;
+import com.sk89q.worldedit.*;
+
+/**
+ *
+ * @author Albert
+ */
+public class EditSession {
+    /**
+     * Stores the original blocks before modification.
+     */
+    private HashMap<Point,Integer> original = new HashMap<Point,Integer>();
+    private HashMap<Point,Integer> current = new HashMap<Point,Integer>();
+
+    /**
+     * Sets a block without changing history.
+     * 
+     * @param x
+     * @param y
+     * @param z
+     * @param blockType
+     * @return Whether the block changed
+     */
+    private boolean rawSetBlock(int x, int y, int z, int blockType) {
+        return etc.getMCServer().e.d(x, y, z, blockType);
+    }
+    
+    /**
+     * Sets the block at position x, y, z with a block type.
+     *
+     * @param x
+     * @param y
+     * @param z
+     * @param blockType
+     * @return Whether the block changed
+     */
+    public boolean setBlock(int x, int y, int z, int blockType) {
+        Point pt = new Point(x, y, z);
+        if (!original.containsKey(pt)) {
+            original.put(pt, getBlock(x, y, z));
+        }
+        current.put(pt, blockType);
+        return rawSetBlock(x, y, z, blockType);
+    }
+
+    /**
+     * Gets the block type at a position x, y, z.
+     *
+     * @param x
+     * @param y
+     * @param z
+     * @return Block type
+     */
+    public int getBlock(int x, int y, int z) {
+        return etc.getMCServer().e.a(x, y, z);
+    }
+
+    /**
+     * Restores all blocks to their initial state.
+     */
+    public void undo() {
+        for (Map.Entry<Point,Integer> entry : original.entrySet()) {
+            Point pt = (Point)entry.getKey();
+            rawSetBlock((int)pt.getX(), (int)pt.getY(),(int)pt.getZ(),
+                        (int)entry.getValue());
+        }
+    }
+
+    /**
+     * Sets to new state.
+     */
+    public void redo() {
+        for (Map.Entry<Point,Integer> entry : current.entrySet()) {
+            Point pt = (Point)entry.getKey();
+            rawSetBlock((int)pt.getX(), (int)pt.getY(),(int)pt.getZ(),
+                        (int)entry.getValue());
+        }
+    }
+
+    /**
+     * Get the number of changed blocks.
+     * 
+     */
+    public int size() {
+        return original.size();
+    }
+}