Mercurial > hg > truffle
diff graal/com.oracle.max.base/src/com/sun/max/collect/HashEntryChainedHashMapping.java @ 3733:e233f5660da4
Added Java files from Maxine project.
author | Thomas Wuerthinger <thomas.wuerthinger@oracle.com> |
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date | Sat, 17 Dec 2011 19:59:18 +0100 |
parents | |
children | bc8527f3071c |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/graal/com.oracle.max.base/src/com/sun/max/collect/HashEntryChainedHashMapping.java Sat Dec 17 19:59:18 2011 +0100 @@ -0,0 +1,93 @@ +/* + * 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<K, V>(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)); + } +}