1 /*
 2  * Copyright (c) 2025, 2026, 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 jdk.incubator.code.internal;
27 
28 import com.sun.tools.javac.tree.JCTree;
29 import com.sun.tools.javac.tree.TreeScanner;
30 
31 public class TreeScannerPrev extends TreeScanner {
32 
33     private JCTree currentNode;
34     private JCTree prevNode;
35 
36     @Override
37     public void scan(JCTree tree) {
38         JCTree prevPrevNode = prevNode;
39         prevNode = currentNode;
40         currentNode = tree;
41         try {
42             super.scan(tree);
43         } finally {
44             currentNode = prevNode;
45             prevNode = prevPrevNode;
46         }
47     }
48 
49     public void scan(JCTree tree, JCTree prevNode) {
50         this.prevNode = null;
51         currentNode = prevNode;
52         scan(tree);
53     }
54 
55     JCTree currentNode() {
56         return currentNode;
57     }
58 
59     JCTree prevNode() {
60         return prevNode;
61     }
62 }