/*
* 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;
import com.sun.max.*;
/**
* Defines the semantics of key comparison in a {@linkplain HashMapping hash based data structure} that delegate to
* {@link Object#equals(Object)} and {@link Object#hashCode()}. There is a {@linkplain #instance(Class) singleton}
* instance of this class.
*/
public final class HashEquality<T> implements HashEquivalence<T> {
private HashEquality() {
}
public boolean equivalent(T object1, T object2) {
if (object1 == null) {
return object2 == null;
}
return object1.equals(object2);
}
public int hashCode(T object) {
if (object == null) {
return 0;
}
return object.hashCode();
}
private static final HashEquality equality = new HashEquality<Object>();
public static <T> HashEquality<T> instance(Class<HashEquality<T>> type) {
return Utils.cast(type, equality);
}
}