| /* |
| * Copyright (c) 2006, 2016, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code 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 |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package com.sun.source.util; |
| |
| import com.sun.source.tree.*; |
| |
| /** |
| * A TreeVisitor that visits all the child tree nodes, and provides |
| * support for maintaining a path for the parent nodes. |
| * To visit nodes of a particular type, just override the |
| * corresponding visitorXYZ method. |
| * Inside your method, call super.visitXYZ to visit descendant |
| * nodes. |
| * |
| * @apiNote |
| * In order to initialize the "current path", the scan must be |
| * started by calling one of the {@code scan} methods. |
| * |
| * @author Jonathan Gibbons |
| * @since 1.6 |
| */ |
| public class TreePathScanner<R, P> extends TreeScanner<R, P> { |
| |
| /** |
| * Scans a tree from a position identified by a TreePath. |
| * @param path the path identifying the node to be scanned |
| * @param p a parameter value passed to visit methods |
| * @return the result value from the visit method |
| */ |
| public R scan(TreePath path, P p) { |
| this.path = path; |
| try { |
| return path.getLeaf().accept(this, p); |
| } finally { |
| this.path = null; |
| } |
| } |
| |
| /** |
| * Scans a single node. |
| * The current path is updated for the duration of the scan. |
| * |
| * @apiNote This method should normally only be called by the |
| * scanner's {@code visit} methods, as part of an ongoing scan |
| * initiated by {@link #scan(TreePath,Object) scan(TreePath, P)}. |
| * The one exception is that it may also be called to initiate |
| * a full scan of a {@link CompilationUnitTree}. |
| * |
| * @return the result value from the visit method |
| */ |
| @Override |
| public R scan(Tree tree, P p) { |
| if (tree == null) |
| return null; |
| |
| TreePath prev = path; |
| path = new TreePath(path, tree); |
| try { |
| return tree.accept(this, p); |
| } finally { |
| path = prev; |
| } |
| } |
| |
| /** |
| * Returns the current path for the node, as built up by the currently |
| * active set of scan calls. |
| * @return the current path |
| */ |
| public TreePath getCurrentPath() { |
| return path; |
| } |
| |
| private TreePath path; |
| } |