/*
 * Copyright 2009-2010 the original author or authors.
 *
 * 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 i 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 net.paoding.rose.jade.rowmapper;

import java.util.Map;

/**
 * 封装一对Key-Value值。
 * 
 * @author 王志亮 [qieqie.wang@gmail.com]
 * @author 廖涵 [in355hz@gmail.com]
 */
public class MapEntryImpl<K, V> implements Map.Entry<K, V> {

    private final K key;

    private V value;

    /**
     * Creates new entry.
     */
    public MapEntryImpl(K k, V v) {
        value = v;
        key = k;
    }

    public final K getKey() {
        return key;
    }

    public final V getValue() {
        return value;
    }

    public final V setValue(V newValue) {
        V oldValue = value;
        value = newValue;
        return oldValue;
    }

    public final boolean equals(Object o) {
        if (!(o instanceof Map.Entry)) return false;
        Map.Entry<?, ?> e = (Map.Entry<?, ?>) o;
        Object k1 = getKey();
        Object k2 = e.getKey();
        if (k1 == k2 || (k1 != null && k1.equals(k2))) {
            Object v1 = getValue();
            Object v2 = e.getValue();
            if (v1 == v2 || (v1 != null && v1.equals(v2))) return true;
        }
        return false;
    }

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

    public final String toString() {
        return getKey() + "=" + getValue();
    }
}