1 /* 2 * Copyright (c) 2006, 2014, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package com.sun.source.util; 27 28 import com.sun.source.doctree.DocTree; 29 30 /** 31 * A DocTreeVisitor that visits all the child tree nodes, and provides 32 * support for maintaining a path for the parent nodes. 33 * To visit nodes of a particular type, just override the 34 * corresponding visitorXYZ method. 35 * Inside your method, call super.visitXYZ to visit descendant 36 * nodes. 37 * 38 * @since 1.8 39 */ 40 @jdk.Exported 41 public class DocTreePathScanner<R, P> extends DocTreeScanner<R, P> { 42 /** 43 * Scans a tree from a position identified by a tree path. 44 * @param path the path 45 * @param p a value to be passed to visitor methods 46 * @return the result returned from the main visitor method 47 */ 48 public R scan(DocTreePath path, P p) { 49 this.path = path; 50 try { 51 return path.getLeaf().accept(this, p); 52 } finally { 53 this.path = null; 54 } 55 } 56 57 /** 58 * Scans a single node. 59 * The current path is updated for the duration of the scan. 60 * @param tree the tree to be scanned 61 * @param p a value to be passed to visitor methods 62 * @return the result returned from the main visitor method 63 */ 64 @Override 65 public R scan(DocTree tree, P p) { 66 if (tree == null) 67 return null; 68 69 DocTreePath prev = path; 70 path = new DocTreePath(path, tree); 71 try { 72 return tree.accept(this, p); 73 } finally { 74 path = prev; 75 } 76 } 77 78 /** 79 * Returns the current path for the node, as built up by the currently 80 * active set of scan calls. 81 * @return the current path 82 */ 83 public DocTreePath getCurrentPath() { 84 return path; 85 } 86 87 private DocTreePath path; 88 }