1 | /* |
2 | * Copyright 2006 Sun Microsystems, Inc. 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. Sun designates this |
8 | * particular file as subject to the "Classpath" exception as provided |
9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
23 | * have any questions. |
24 | */ |
25 | |
26 | package com.sun.source.util; |
27 | |
28 | import com.sun.source.tree.*; |
29 | |
30 | /** |
31 | * A TreeVisitor 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 | * @author Jonathan Gibbons |
39 | * @since 1.6 |
40 | */ |
41 | public class TreePathScanner<R, P> extends TreeScanner<R, P> { |
42 | |
43 | /** |
44 | * Scan a tree from a position identified by a TreePath. |
45 | */ |
46 | public R scan(TreePath path, P p) { |
47 | this.path = path; |
48 | try { |
49 | return path.getLeaf().accept(this, p); |
50 | } finally { |
51 | this.path = null; |
52 | } |
53 | } |
54 | |
55 | /** |
56 | * Scan a single node. |
57 | * The current path is updated for the duration of the scan. |
58 | */ |
59 | @Override |
60 | public R scan(Tree tree, P p) { |
61 | if (tree == null) |
62 | return null; |
63 | |
64 | TreePath prev = path; |
65 | path = new TreePath(path, tree); |
66 | try { |
67 | return tree.accept(this, p); |
68 | } finally { |
69 | path = prev; |
70 | } |
71 | } |
72 | |
73 | /** |
74 | * Get the current path for the node, as built up by the currently |
75 | * active set of scan calls. |
76 | */ |
77 | public TreePath getCurrentPath() { |
78 | return path; |
79 | } |
80 | |
81 | private TreePath path; |
82 | } |