/*******************************************************************************
* Copyright (c) 2006, 2015 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
* Daniel Kruegler - bug 137435
* Matthew Hall - bug 303847
******************************************************************************/
package org.eclipse.core.internal.databinding;
/**
* Used for wrapping objects that define their own implementations of equals()
* and hashCode() when putting them in sets or hashmaps to ensure identity
* comparison.
*
* @since 1.0
*
*/
public class IdentityWrapper {
private static final IdentityWrapper NULL_WRAPPER = new IdentityWrapper(
null);
/**
* @param obj
* the object to wrap
* @return an IdentityWrapper wrapping the specified object
*/
public static IdentityWrapper wrap(Object obj) {
return obj == null ? NULL_WRAPPER : new IdentityWrapper(obj);
}
final Object o;
/**
* @param o
*/
private IdentityWrapper(Object o) {
this.o = o;
}
/**
* @return the unwrapped object
*/
public Object unwrap() {
return o;
}
@Override
public boolean equals(Object obj) {
if (obj == null || obj.getClass() != IdentityWrapper.class) {
return false;
}
return o == ((IdentityWrapper) obj).o;
}
@Override
public int hashCode() {
return System.identityHashCode(o);
}
}