001    /*
002     *  This file is part of the Jikes RVM project (http://jikesrvm.org).
003     *
004     *  This file is licensed to You under the Eclipse Public License (EPL);
005     *  You may not use this file except in compliance with the License. You
006     *  may obtain a copy of the License at
007     *
008     *      http://www.opensource.org/licenses/eclipse-1.0.php
009     *
010     *  See the COPYRIGHT.txt file distributed with this work for information
011     *  regarding copyright ownership.
012     */
013    package org.jikesrvm.util;
014    
015    import org.jikesrvm.runtime.Magic;
016    import org.jikesrvm.util.HashMapRVM.Bucket;
017    
018    /**
019     * The same as {@link HashMapRVM} except object identities determine equality
020     * not the equals method.
021     */
022    public final class IdentityHashMapRVM<K, V> extends AbstractHashMapRVM<K, V> {
023      @Override
024      boolean same(K k1, K k2) {
025        return k1 == k2;
026      }
027    
028      @Override
029      protected int hashTheKey(K key) {
030        if (!org.jikesrvm.VM.runningVM) {
031          return Magic.bootImageIdentityHashCode(key);
032        } else {
033          return System.identityHashCode(key);
034        }
035      }
036    
037      @Override
038      AbstractBucket<K,V> createNewBucket(K key, V value, AbstractBucket<K, V> next) {
039        return new Bucket<K,V>(key, value, next);
040      }
041    
042      public IdentityHashMapRVM() {
043        super(DEFAULT_SIZE);
044      }
045    
046      public IdentityHashMapRVM(int size) {
047        super(size);
048      }
049    }