luni/src/main/java/java/util/MapEntry.java

/*
 *  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 java.util;

/**
 * MapEntry is an internal class which provides an implementation of Map.Entry.
 */
class MapEntry<K, V> implements Map.Entry<K, V>, Cloneable {

    K key;
    V value;

    interface Type<RT, KT, VT> {
        RT get(MapEntry<KT, VT> entry);
    }

    MapEntry(K theKey) {
        key = theKey;
    }

    MapEntry(K theKey, V theValue) {
        key = theKey;
        value = theValue;
    }

    @Override
    public Object clone() {
        try {
            return super.clone();
        } catch (CloneNotSupportedException e) {
            throw new AssertionError(e);
        }
    }

    @Override
    public boolean equals(Object object) {
        if (this == object) {
            return true;
        }
        if (object instanceof Map.Entry) {
            Map.Entry<?, ?> entry = (Map.Entry<?, ?>) object;
            return (key == null ? entry.getKey() == null : key.equals(entry
                    .getKey()))
                    && (value == null ? entry.getValue() == null : value
                            .equals(entry.getValue()));
        }
        return false;
    }

    public K getKey() {
        return key;
    }

    public V getValue() {
        return value;
    }

    @Override
    public int hashCode() {
        return (key == null ? 0 : key.hashCode())
                ^ (value == null ? 0 : value.hashCode());
    }

    public V setValue(V object) {
        V result = value;
        value = object;
        return result;
    }

    @Override
    public String toString() {
        return key + "=" + value;
    }
}