org.apache.openjpa.lib.util.collections.AbstractKeyValue Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.openjpa.lib.util.collections;
/**
* Abstract pair class to assist with creating KeyValue
* and {@link java.util.Map.Entry Map.Entry} implementations.
*
* @param the type of keys
* @param the type of values
* @since 3.0
*/
public abstract class AbstractKeyValue implements KeyValue {
/** The key */
private K key;
/** The value */
private V value;
/**
* Constructs a new pair with the specified 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 AbstractKeyValue(final K key, final V value) {
super();
this.key = key;
this.value = value;
}
/**
* Gets the key from the pair.
*
* @return the key
*/
@Override
public K getKey() {
return key;
}
protected K setKey(final K key) {
final K old = this.key;
this.key = key;
return old;
}
/**
* Gets the value from the pair.
*
* @return the value
*/
@Override
public V getValue() {
return value;
}
protected V setValue(final V value) {
final V old = this.value;
this.value = value;
return old;
}
/**
* Gets a debugging String view of the pair.
*
* @return a String view of the entry
*/
@Override
public String toString() {
return new StringBuilder()
.append(getKey())
.append('=')
.append(getValue())
.toString();
}
}