Undo move.

src/com/jpexs/decompiler/flash/easygui/UndoManager.java

@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2024 JPEXS
+ *
+ * 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/>.
+ */
+package com.jpexs.decompiler.flash.easygui;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ *
+ * @author JPEXS
+ */
+public class UndoManager {
+    private int historyPos = 0;
+    private final List<DoableOperation> history = new ArrayList<>();
+    
+    private final List<Runnable> changeListeners = new ArrayList<>();
+    
+    public void addChangeListener(Runnable listener) {
+        changeListeners.add(listener);
+    }
+    
+    public void removeChangeListener(Runnable listener) {
+        changeListeners.remove(listener);
+    }
+    
+    private void fireChange() {
+        for (Runnable listener : changeListeners) {
+            listener.run();
+        }
+    }
+    
+    public void doOperation(DoableOperation doableOperation) {
+        //drop redos
+        while(history.size() > historyPos) {
+            history.remove(historyPos);
+        }
+        
+        history.add(doableOperation);
+        historyPos++;
+        doableOperation.doOperation();
+        fireChange();
+    }
+    
+    public boolean canUndo() {
+        return historyPos > 0;
+    }
+    
+    public String getUndoName() {
+        if (!canUndo()) {
+            return null;
+        }
+        return history.get(historyPos - 1).getDescription();
+    }        
+    
+    public void undo() {
+        if (historyPos == 0) {
+            return;
+        }
+        historyPos--;
+        history.get(historyPos).undoOperation();
+        fireChange();
+    }
+    
+    public void redo() {
+        if (!canRedo()) {
+            return;
+        }
+        history.get(historyPos).doOperation();
+        historyPos++;
+        fireChange();
+    }
+    
+    public String getRedoName() {
+        if (!canRedo()) {
+            return null;
+        }
+        return history.get(historyPos).getDescription();
+    }
+    
+    public boolean canRedo() {
+        return history.size() > historyPos;
+    }
+}