/*
* Copyright 1999-2004 The Apache Software Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.collections;
import java.util.Map;
/** A default implementation of {@link java.util.Map.Entry}
*
* @since 1.0
* @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
* @author <a href="mailto:mas@apache.org">Michael A. Smith</a>
*/
public class DefaultMapEntry implements Map.Entry {
private Object key;
private Object value;
/**
* Constructs a new <Code>DefaultMapEntry</Code> with a null key
* and null value.
*/
public DefaultMapEntry() {
}
/**
* Constructs a new <Code>DefaultMapEntry</Code> with the given
* key and given value.
*
* @param key the key for the entry, may be null
* @param value the value for the entyr, may be null
*/
public DefaultMapEntry(Object key, Object value) {
this.key = key;
this.value = value;
}
/**
* Implemented per API documentation of
* {@link java.util.Map.Entry#equals(Object)}
**/
public boolean equals(Object o) {
if( o == null ) return false;
if( o == this ) return true;
if ( ! (o instanceof Map.Entry ) )
return false;
Map.Entry e2 = (Map.Entry)o;
return ((getKey() == null ?
e2.getKey() == null : getKey().equals(e2.getKey())) &&
(getValue() == null ?
e2.getValue() == null : getValue().equals(e2.getValue())));
}
/**
* Implemented per API documentation of
* {@link java.util.Map.Entry#hashCode()}
**/
public int hashCode() {
return ( ( getKey() == null ? 0 : getKey().hashCode() ) ^
( getValue() == null ? 0 : getValue().hashCode() ) );
}
// Map.Entry interface
//-------------------------------------------------------------------------
/**
* Returns the key.
*
* @return the key
*/
public Object getKey() {
return key;
}
/**
* Returns the value.
*
* @return the value
*/
public Object getValue() {
return value;
}
// Properties
//-------------------------------------------------------------------------
/**
* Sets the key. This method does not modify any map.
*
* @param key the new key
*/
public void setKey(Object key) {
this.key = key;
}
/** Note that this method only sets the local reference inside this object and
* does not modify the original Map.
*
* @return the old value of the value
* @param value the new value
*/
public Object setValue(Object value) {
Object answer = this.value;
this.value = value;
return answer;
}
}