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/*
* Copyright 2004-2014 ICEsoft Technologies Canada Corp.
*
* 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.icefaces.ace.model;
import java.util.Map;
/**
* This class provides a skeletal implementation of the Entry
* interface, to minimize the effort required to implement this interface.
*
* This class is a member of the
*
* Java Collections Framework.
*
* @param the type of keys maintained by this map
* @param the type of mapped values
*
* @author Josh Bloch
* @author Neal Gafter
* @version %I%, %G%
* @see java.util.Map
* @see java.util.Collection
* @since 1.2
*/
public class SimpleEntry implements Map.Entry, java.io.Serializable
{
private static final long serialVersionUID = -8499721149061103585L;
private final K key;
private V value;
/**
* Creates an entry representing a mapping from the specified
* key to the specified value.
*
* @param key the key represented by this entry
* @param value the value represented by this entry
*/
public SimpleEntry(K key, V value) {
this.key = key;
this.value = value;
}
/**
* Creates an entry representing the same mapping as the
* specified entry.
*
* @param entry the entry to copy
*/
public SimpleEntry(Map.Entry entry) {
this.key = entry.getKey();
this.value = entry.getValue();
}
/**
* Returns the key corresponding to this entry.
*
* @return the key corresponding to this entry
*/
public K getKey() {
return key;
}
/**
* Returns the value corresponding to this entry.
*
* @return the value corresponding to this entry
*/
public V getValue() {
return value;
}
/**
* Replaces the value corresponding to this entry with the specified
* value.
*
* @param value new value to be stored in this entry
* @return the old value corresponding to the entry
*/
public V setValue(V value) {
V oldValue = this.value;
this.value = value;
return oldValue;
}
/**
* Compares the specified object with this entry for equality.
* Returns {@code true} if the given object is also a map entry and
* the two entries represent the same mapping. More formally, two
* entries {@code e1} and {@code e2} represent the same mapping
* if
* (e1.getKey()==null ?
* e2.getKey()==null :
* e1.getKey().equals(e2.getKey()))
* &&
* (e1.getValue()==null ?
* e2.getValue()==null :
* e1.getValue().equals(e2.getValue()))
* This ensures that the {@code equals} method works properly across
* different implementations of the {@code Map.Entry} interface.
*
* @param o object to be compared for equality with this map entry
* @return {@code true} if the specified object is equal to this map
* entry
* @see #hashCode
*/
public boolean equals(Object o) {
if (!(o instanceof Map.Entry))
return false;
Map.Entry e = (Map.Entry)o;
return eq(key, e.getKey()) && eq(value, e.getValue());
}
/**
* Returns the hash code value for this map entry. The hash code
* of a map entry {@code e} is defined to be:
* (e.getKey()==null ? 0 : e.getKey().hashCode()) ^
* (e.getValue()==null ? 0 : e.getValue().hashCode())
* This ensures that {@code e1.equals(e2)} implies that
* {@code e1.hashCode()==e2.hashCode()} for any two Entries
* {@code e1} and {@code e2}, as required by the general
* contract of {@link Object#hashCode}.
*
* @return the hash code value for this map entry
* @see #equals
*/
public int hashCode() {
return (key == null ? 0 : key.hashCode()) ^
(value == null ? 0 : value.hashCode());
}
/**
* Returns a String representation of this map entry. This
* implementation returns the string representation of this
* entry's key followed by the equals character ("=")
* followed by the string representation of this entry's value.
*
* @return a String representation of this map entry
*/
public String toString() {
return key + "=" + value;
}
private static boolean eq(Object o1, Object o2) {
return o1 == null ? o2 == null : o1.equals(o2);
}
}