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diff --git a/javaparser-core/src/main/java/com/github/javaparser/HasParentNode.java b/javaparser-core/src/main/java/com/github/javaparser/HasParentNode.java
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+++ b/javaparser-core/src/main/java/com/github/javaparser/HasParentNode.java
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+/*
+ * Copyright (C) 2007-2010 Júlio Vilmar Gesser.
+ * Copyright (C) 2011, 2013-2016 The JavaParser Team.
+ *
+ * This file is part of JavaParser.
+ *
+ * JavaParser can be used either under the terms of
+ * a) the GNU Lesser General Public License as published by
+ *     the Free Software Foundation, either version 3 of the License, or
+ *     (at your option) any later version.
+ * b) the terms of the Apache License
+ *
+ * You should have received a copy of both licenses in LICENCE.LGPL and
+ * LICENCE.APACHE. Please refer to those files for details.
+ *
+ * JavaParser 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 Lesser General Public License for more details.
+ */
+
+package com.github.javaparser;
+
+import com.github.javaparser.ast.Node;
+import com.github.javaparser.ast.observer.Observable;
+
+import java.util.Optional;
+
+/**
+ * An object that has a parent node.
+ */
+public interface HasParentNode<T> extends Observable {
+
+    /**
+     * Return the parent node or null, if no parent is set.
+     */
+    Optional<Node> getParentNode();
+
+    /**
+     * Set the parent node.
+     *
+     * @param parentNode the parent node or null, to set no parent
+     * @return return <i>this</i>
+     */
+    T setParentNode(Node parentNode);
+
+    /**
+     * <i>this</i> for everything except NodeLists. NodeLists use their parent as their children parent.
+     */
+    Node getParentNodeForChildren();
+
+    /**
+     * Get the ancestor of the node having the given type, or null if no ancestor of the given type is found.
+     */
+    default <N> Optional<N> getAncestorOfType(Class<N> classType) {
+        Node parent = getParentNode().orElse(null);
+        while (parent != null) {
+            if (classType.isAssignableFrom(parent.getClass())) {
+                return Optional.of(classType.cast(parent));
+            }
+            parent = parent.getParentNode().orElse(null);
+        }
+        return Optional.empty();
+    }
+}