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comparison graal/com.oracle.max.base/src/com/sun/max/collect/LinkedIdentityHashMap.java @ 3733:e233f5660da4

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Added Java files from Maxine project.
author Thomas Wuerthinger <thomas.wuerthinger@oracle.com>
date Sat, 17 Dec 2011 19:59:18 +0100
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children bc8527f3071c
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3732:3e2e8b8abdaf 3733:e233f5660da4
1 /*
2 * Copyright (c) 2007, 2011, 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.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23 package com.sun.max.collect;
24
25 import java.util.*;
26
27 import com.sun.max.*;
28
29 /**
30 */
31 public class LinkedIdentityHashMap<K, V> extends IdentityHashMap<K, V> implements Iterable<K> {
32
33 private final LinkedList<K> order = new LinkedList<K>();
34
35 public LinkedIdentityHashMap() {
36 }
37
38 public LinkedIdentityHashMap(int expectedMaxSize) {
39 super(expectedMaxSize);
40 }
41
42 @Override
43 public V put(K key, V value) {
44 final V oldValue = super.put(key, value);
45 if (oldValue == null) {
46 if (value != null) {
47 order.add(key);
48 }
49 } else {
50 if (value == null) {
51 order.remove(key);
52 }
53 }
54 return oldValue;
55 }
56
57 public Iterator<K> iterator() {
58 return order.iterator();
59 }
60
61 public K first() {
62 return order.getFirst();
63 }
64
65 public K last() {
66 return order.getLast();
67 }
68
69 @Override
70 public boolean equals(Object other) {
71 if (other instanceof LinkedIdentityHashMap) {
72 final LinkedIdentityHashMap map = (LinkedIdentityHashMap) other;
73 if (order.size() != map.order.size()) {
74 return false;
75 }
76 final Iterator iterator = map.order.iterator();
77 for (K key : order) {
78 if (key != iterator.next() || !get(key).equals(map.get(key))) {
79 return false;
80 }
81 }
82 return true;
83 }
84 return false;
85 }
86
87 @Override
88 public int hashCode() {
89 return order.hashCode();
90 }
91
92 @Override
93 public LinkedIdentityHashMap<K, V> clone() {
94 return Utils.cast(super.clone());
95 }
96
97 public Collection<K> toCollection() {
98 return keySet();
99 }
100 }