/*
***************************************************************************************
* Copyright (C) 2006 EsperTech, Inc. All rights reserved. *
* http://www.espertech.com/esper *
* http://www.espertech.com *
* ---------------------------------------------------------------------------------- *
* The software in this package is published under the terms of the GPL license *
* a copy of which has been included with this distribution in the license.txt file. *
***************************************************************************************
*/
/*
* Credit: Apache Commons Collections
*/
package com.espertech.esper.collection.apachecommons;
import java.util.Map;
/**
* Abstract Pair class to assist with creating correct
* {@link java.util.Map.Entry Map.Entry} implementations.
*
* @author James Strachan
* @author Michael A. Smith
* @author Neil O'Toole
* @author Stephen Colebourne
* @version $Revision$ $Date$
* @since Commons Collections 3.0
*/
public abstract class AbstractMapEntry extends AbstractKeyValue implements Map.Entry {
/**
* Constructs a new entry with the given key and given value.
*
* @param key the key for the entry, may be null
* @param value the value for the entry, may be null
*/
protected AbstractMapEntry(Object key, Object value) {
super(key, value);
}
// Map.Entry interface
//-------------------------------------------------------------------------
/**
* Sets the value stored in this <code>Map.Entry</code>.
* <p>
* This <code>Map.Entry</code> is not connected to a Map, so only the
* local data is changed.
*
* @param value the new value
* @return the previous value
*/
public Object setValue(Object value) {
Object answer = this.value;
this.value = value;
return answer;
}
/**
* Compares this <code>Map.Entry</code> with another <code>Map.Entry</code>.
* <p>
* Implemented per API documentation of {@link java.util.Map.Entry#equals(Object)}
*
* @param obj the object to compare to
* @return true if equal key and value
*/
public boolean equals(Object obj) {
if (obj == this) {
return true;
}
if (!(obj instanceof Map.Entry)) {
return false;
}
Map.Entry other = (Map.Entry) obj;
return
(getKey() == null ? other.getKey() == null : getKey().equals(other.getKey())) &&
(getValue() == null ? other.getValue() == null : getValue().equals(other.getValue()));
}
/**
* Gets a hashCode compatible with the equals method.
* <p>
* Implemented per API documentation of {@link java.util.Map.Entry#hashCode()}
*
* @return a suitable hash code
*/
public int hashCode() {
return (getKey() == null ? 0 : getKey().hashCode()) ^
(getValue() == null ? 0 : getValue().hashCode());
}
}