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 public class DocTreePathScanner<R, P> extends DocTreeScanner<R, P> { 41 /** 42 * Constructs a {@code DocTreePathScanner}. 43 */ 44 public DocTreePathScanner() {} 45 46 /** 47 * Scans a tree from a position identified by a tree path. 48 * @param path the path 49 * @param p a value to be passed to visitor methods 50 * @return the result returned from the main visitor method 51 */ 52 public R scan(DocTreePath path, P p) { 53 this.path = path; 54 try { 55 return path.getLeaf().accept(this, p); 56 } finally { 57 this.path = null; 58 } 59 } 60 61 /** 62 * Scans a single node. 63 * The current path is updated for the duration of the scan. 64 * @param tree the tree to be scanned 65 * @param p a value to be passed to visitor methods 66 * @return the result returned from the main visitor method 67 */ 68 @Override 69 public R scan(DocTree tree, P p) { 70 if (tree == null) 71 return null; 72 73 DocTreePath prev = path; 74 path = new DocTreePath(path, tree); 75 try { 76 return tree.accept(this, p); 77 } finally { 78 path = prev; 79 } 80 } 81 82 /** 83 * Returns the current path for the node, as built up by the currently 84 * active set of scan calls. 85 * @return the current path 86 */ 87 public DocTreePath getCurrentPath() { 88 return path; 89 } 90 91 private DocTreePath path; 92 }