Mercurial > hg > truffle
view graal/com.oracle.max.base/src/com/sun/max/collect/HashEntryChainedHashMapping.java @ 4266:e2499e6d8aa7
Merge
author | Lukas Stadler <lukas.stadler@jku.at> |
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date | Wed, 11 Jan 2012 16:31:46 +0100 |
parents | bc8527f3071c |
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/* * Copyright (c) 2007, 2011, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package com.sun.max.collect; /** * A chained hash table whose {@linkplain HashEntry entries} record the hash of the key. This can provide better * performance improvement when the cost of computing the key's hash code is high. */ public class HashEntryChainedHashMapping<K, V> extends ChainedHashMapping<K, V> { public static class HashEntry<K, V> extends DefaultEntry<K, V> { final int hashOfKey; public HashEntry(int hashOfKey, K key, V value, Entry<K, V> next) { super(key, value, next); this.hashOfKey = hashOfKey; } } /** * Creates a chained hash table whose entries record the hash of the key. * * @param equivalence * the semantics of key comparison and hashing. If {@code null}, then {@link HashEquality} is used. * @param initialCapacity * the initial capacity of the table */ public HashEntryChainedHashMapping(HashEquivalence<K> equivalence, int initialCapacity) { super(equivalence, initialCapacity); } /** * Creates a chained hash table with {@linkplain HashEquality equality} key semantics whose entries record the hash * of the key. * * @param initialCapacity * the initial capacity of the table */ public HashEntryChainedHashMapping(int initialCapacity) { super(initialCapacity); } /** * Creates a chained hash table with an initial capacity of {@value ChainedHashMapping#DEFAULT_INITIAL_CAPACITY} * whose entries record the hash of the key. * * @param equivalence * the semantics of key comparison and hashing. If {@code null}, then {@link HashEquality} is used. */ public HashEntryChainedHashMapping(HashEquivalence<K> equivalence) { super(equivalence); } /** * Creates a chained hash table with {@linkplain HashEquality equality} key semantics and an initial capacity of * {@value ChainedHashMapping#DEFAULT_INITIAL_CAPACITY} whose entries record the hash of the key. */ public HashEntryChainedHashMapping() { super(); } @Override protected Entry<K, V> createEntry(int hashOfKey, K key, V value, Entry<K, V> next) { return new HashEntryChainedHashMapping.HashEntry<>(hashOfKey, key, value, next); } @Override protected boolean matches(Entry<K, V> entry, K key, int hashForKey) { final K entryKey = entry.key(); return entryKey == key || (hashForKey == ((HashEntryChainedHashMapping.HashEntry) entry).hashOfKey && key.equals(entryKey)); } }