01: /*
02: * Copyright (C) 2004 TiongHiang Lee
03: *
04: * This library is free software; you can redistribute it and/or
05: * modify it under the terms of the GNU Lesser General Public
06: * License as published by the Free Software Foundation; either
07: * version 2.1 of the License, or (at your option) any later version.
08: *
09: * This library is distributed in the hope that it will be useful,
10: * but WITHOUT ANY WARRANTY; without even the implied warranty of
11: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12: * Lesser General Public License for more details.
13: *
14: * You should have received a copy of the GNU Lesser General Public
15: * License along with this library; if not, write to the Free Software
16: * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17: *
18: * Email: thlee@onemindsoft.org
19: */
20:
21: package org.onemind.swingweb.util;
22:
23: import org.onemind.commons.java.datastructure.InheritableValueMap;
24:
25: /**
26: * Lazily create
27: * @author TiongHiang Lee (thlee@onemindsoft.org)
28: *
29: */
30: public abstract class LazyInheritedValueMap extends InheritableValueMap {
31:
32: /**
33: * {@inheritDoc}
34: */
35: public Object resolve(Class c) {
36: if (keySet().contains(c)) { //this is done before
37: return super .resolve(c);
38: } else {
39: //first, use lazy resolve
40: Object obj = delayedResolve(c);
41: put(c, obj); //mark as done regardless result
42: if (obj != null) {
43: return obj;
44: }
45: //secondly, try the superclass
46: if (c.getSuperclass() != null) {
47: return resolve(c.getSuperclass());
48: } else {
49: return null;
50: }
51: }
52: }
53:
54: /**
55: * @param c the class
56: * @return the object
57: */
58: protected abstract Object delayedResolve(Class c);
59: }
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