01: /*
02: * Distributed as part of c3p0 v.0.9.1.2
03: *
04: * Copyright (C) 2005 Machinery For Change, Inc.
05: *
06: * Author: Steve Waldman <swaldman@mchange.com>
07: *
08: * This library is free software; you can redistribute it and/or modify
09: * it under the terms of the GNU Lesser General Public License version 2.1, as
10: * published by the Free Software Foundation.
11: *
12: * This software is distributed in the hope that it will be useful,
13: * but WITHOUT ANY WARRANTY; without even the implied warranty of
14: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15: * GNU Lesser General Public License for more details.
16: *
17: * You should have received a copy of the GNU Lesser General Public License
18: * along with this software; see the file LICENSE. If not, write to the
19: * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
20: * Boston, MA 02111-1307, USA.
21: */
22:
23: package com.mchange.v1.identicator;
24:
25: import java.lang.ref.*;
26:
27: // revisit equals() if ever made non-final
28:
29: final class WeakIdHashKey extends IdHashKey {
30: Ref keyRef;
31: int hash;
32:
33: public WeakIdHashKey(Object keyObj, Identicator id,
34: ReferenceQueue rq) {
35: super (id);
36:
37: if (keyObj == null)
38: throw new UnsupportedOperationException(
39: "Collection does not accept nulls!");
40:
41: this .keyRef = new Ref(keyObj, rq);
42: this .hash = id.hash(keyObj);
43: }
44:
45: public Ref getInternalRef() {
46: return this .keyRef;
47: }
48:
49: public Object getKeyObj() {
50: return keyRef.get();
51: }
52:
53: public boolean equals(Object o) {
54: // fast type-exact match for final class
55: if (o instanceof WeakIdHashKey) {
56: WeakIdHashKey other = (WeakIdHashKey) o;
57: if (this .keyRef == other.keyRef)
58: return true;
59: else {
60: Object myKeyObj = this .keyRef.get();
61: Object oKeyObj = other.keyRef.get();
62: if (myKeyObj == null || oKeyObj == null)
63: return false;
64: else
65: return id.identical(myKeyObj, oKeyObj);
66: }
67: } else
68: return false;
69: }
70:
71: public int hashCode() {
72: return hash;
73: }
74:
75: class Ref extends WeakReference {
76: public Ref(Object referant, ReferenceQueue rq) {
77: super (referant, rq);
78: }
79:
80: WeakIdHashKey getKey() {
81: return WeakIdHashKey.this;
82: }
83: }
84: }
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