duke@1: /*
darcy@1590:  * Copyright (c) 2006, 2013, Oracle and/or its affiliates. All rights reserved.
duke@1:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@1:  *
duke@1:  * This code is free software; you can redistribute it and/or modify it
duke@1:  * under the terms of the GNU General Public License version 2 only, as
ohair@554:  * published by the Free Software Foundation.  Oracle designates this
duke@1:  * particular file as subject to the "Classpath" exception as provided
ohair@554:  * by Oracle in the LICENSE file that accompanied this code.
duke@1:  *
duke@1:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@1:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@1:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@1:  * version 2 for more details (a copy is included in the LICENSE file that
duke@1:  * accompanied this code).
duke@1:  *
duke@1:  * You should have received a copy of the GNU General Public License version
duke@1:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@1:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@1:  *
ohair@554:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
ohair@554:  * or visit www.oracle.com if you need additional information or have any
ohair@554:  * questions.
duke@1:  */
duke@1: 
duke@1: package com.sun.source.util;
duke@1: 
duke@1: import com.sun.source.tree.*;
duke@1: 
duke@1: /**
duke@1:  * A TreeVisitor that visits all the child tree nodes, and provides
duke@1:  * support for maintaining a path for the parent nodes.
duke@1:  * To visit nodes of a particular type, just override the
duke@1:  * corresponding visitorXYZ method.
duke@1:  * Inside your method, call super.visitXYZ to visit descendant
duke@1:  * nodes.
duke@1:  *
duke@1:  * @author Jonathan Gibbons
duke@1:  * @since 1.6
duke@1:  */
darcy@1590: @jdk.Supported
duke@1: public class TreePathScanner<R, P> extends TreeScanner<R, P> {
duke@1: 
duke@1:     /**
duke@1:      * Scan a tree from a position identified by a TreePath.
duke@1:      */
duke@1:     public R scan(TreePath path, P p) {
duke@1:         this.path = path;
duke@1:         try {
duke@1:             return path.getLeaf().accept(this, p);
duke@1:         } finally {
duke@1:             this.path = null;
duke@1:         }
duke@1:     }
duke@1: 
duke@1:     /**
duke@1:      * Scan a single node.
duke@1:      * The current path is updated for the duration of the scan.
duke@1:      */
duke@1:     @Override
duke@1:     public R scan(Tree tree, P p) {
duke@1:         if (tree == null)
duke@1:             return null;
duke@1: 
duke@1:         TreePath prev = path;
duke@1:         path = new TreePath(path, tree);
duke@1:         try {
duke@1:             return tree.accept(this, p);
duke@1:         } finally {
duke@1:             path = prev;
duke@1:         }
duke@1:     }
duke@1: 
duke@1:     /**
duke@1:      * Get the current path for the node, as built up by the currently
duke@1:      * active set of scan calls.
duke@1:      */
duke@1:     public TreePath getCurrentPath() {
duke@1:         return path;
duke@1:     }
duke@1: 
duke@1:     private TreePath path;
duke@1: }