01: /*
02: [The "BSD licence"]
03: Copyright (c) 2005-2006 Terence Parr
04: All rights reserved.
05:
06: Redistribution and use in source and binary forms, with or without
07: modification, are permitted provided that the following conditions
08: are met:
09: 1. Redistributions of source code must retain the above copyright
10: notice, this list of conditions and the following disclaimer.
11: 2. Redistributions in binary form must reproduce the above copyright
12: notice, this list of conditions and the following disclaimer in the
13: documentation and/or other materials provided with the distribution.
14: 3. The name of the author may not be used to endorse or promote products
15: derived from this software without specific prior written permission.
16:
17: THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18: IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19: OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20: IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21: INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22: NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23: DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24: THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25: (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26: THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27: */
28: package org.antlr.runtime.tree;
29:
30: /** A generic doubly-linked tree implementation with no payload.
31: * You must subclass to actually have any user data.
32: * TODO: do we really need/want this?
33: */
34: public abstract class DoubleLinkTree extends BaseTree {
35: protected DoubleLinkTree parent;
36:
37: public DoubleLinkTree getParent() {
38: return parent;
39: }
40:
41: public void setParent(DoubleLinkTree t) {
42: parent = t;
43: }
44:
45: public void addChild(BaseTree t) {
46: super .addChild(t);
47: ((DoubleLinkTree) t).setParent((DoubleLinkTree) this );
48: }
49:
50: public void setChild(int i, BaseTree t) {
51: super .setChild(i, t);
52: ((DoubleLinkTree) t).setParent((DoubleLinkTree) this);
53: }
54: }
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