diff --git a/ganttzk/src/main/java/org/zkoss/ganttz/util/PreAndPostNotReentrantActionsWrapper.java b/ganttzk/src/main/java/org/zkoss/ganttz/util/PreAndPostNotReentrantActionsWrapper.java
new file mode 100644
index 000000000..7d3f530f7
--- /dev/null
+++ b/ganttzk/src/main/java/org/zkoss/ganttz/util/PreAndPostNotReentrantActionsWrapper.java
@@ -0,0 +1,64 @@
+/*
+ * This file is part of ###PROJECT_NAME###
+ *
+ * Copyright (C) 2009 Fundación para o Fomento da Calidade Industrial e
+ *                    Desenvolvemento Tecnolóxico de Galicia
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.zkoss.ganttz.util;
+
+import org.apache.commons.lang.Validate;
+
+/**
+ * @author Óscar González Fernández <ogonzalez@igalia.com>
+ */
+public abstract class PreAndPostNotReentrantActionsWrapper {
+
+    public interface IAction {
+        public void doAction();
+    }
+
+    private final ThreadLocal<Boolean> inside = new ThreadLocal<Boolean>() {
+        @Override
+        protected Boolean initialValue() {
+            return false;
+        }
+    };
+
+    public void doAction(IAction action) {
+        Validate.notNull(action);
+        if (inside.get()) {
+            action.doAction();
+        } else {
+            executeWithPreAndPostActions(action);
+        }
+    }
+
+    private void executeWithPreAndPostActions(IAction action) {
+        preAction();
+        inside.set(true);
+        try {
+            action.doAction();
+        } finally {
+            inside.set(false);
+            postAction();
+        }
+    }
+
+    protected abstract void postAction();
+
+    protected abstract void preAction();
+
+}