Mercurial > hg > truffle

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

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Added Java files from Maxine project.
author Thomas Wuerthinger <thomas.wuerthinger@oracle.com>
date Sat, 17 Dec 2011 19:59:18 +0100
parents
children bc8527f3071c
comparison
equal deleted inserted replaced
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 /**
26 * A chained hash table whose {@linkplain HashEntry entries} record the hash of the key. This can provide better
27 * performance improvement when the cost of computing the key's hash code is high.
28 */
29 public class HashEntryChainedHashMapping<K, V> extends ChainedHashMapping<K, V> {
30
31 public static class HashEntry<K, V> extends DefaultEntry<K, V> {
32
33 final int hashOfKey;
34
35 public HashEntry(int hashOfKey, K key, V value, Entry<K, V> next) {
36 super(key, value, next);
37 this.hashOfKey = hashOfKey;
38 }
39 }
40
41 /**
42 * Creates a chained hash table whose entries record the hash of the key.
43 *
44 * @param equivalence
45 * the semantics of key comparison and hashing. If {@code null}, then {@link HashEquality} is used.
46 * @param initialCapacity
47 * the initial capacity of the table
48 */
49 public HashEntryChainedHashMapping(HashEquivalence<K> equivalence, int initialCapacity) {
50 super(equivalence, initialCapacity);
51 }
52
53 /**
54 * Creates a chained hash table with {@linkplain HashEquality equality} key semantics whose entries record the hash
55 * of the key.
56 *
57 * @param initialCapacity
58 * the initial capacity of the table
59 */
60 public HashEntryChainedHashMapping(int initialCapacity) {
61 super(initialCapacity);
62 }
63
64 /**
65 * Creates a chained hash table with an initial capacity of {@value ChainedHashMapping#DEFAULT_INITIAL_CAPACITY}
66 * whose entries record the hash of the key.
67 *
68 * @param equivalence
69 * the semantics of key comparison and hashing. If {@code null}, then {@link HashEquality} is used.
70 */
71 public HashEntryChainedHashMapping(HashEquivalence<K> equivalence) {
72 super(equivalence);
73 }
74
75 /**
76 * Creates a chained hash table with {@linkplain HashEquality equality} key semantics and an initial capacity of
77 * {@value ChainedHashMapping#DEFAULT_INITIAL_CAPACITY} whose entries record the hash of the key.
78 */
79 public HashEntryChainedHashMapping() {
80 super();
81 }
82
83 @Override
84 protected Entry<K, V> createEntry(int hashOfKey, K key, V value, Entry<K, V> next) {
85 return new HashEntryChainedHashMapping.HashEntry<K, V>(hashOfKey, key, value, next);
86 }
87
88 @Override
89 protected boolean matches(Entry<K, V> entry, K key, int hashForKey) {
90 final K entryKey = entry.key();
91 return entryKey == key || (hashForKey == ((HashEntryChainedHashMapping.HashEntry) entry).hashOfKey && key.equals(entryKey));
92 }
93 }