hugegraph-pd/hg-pd-common/src/main/java/org/apache/hugegraph/pd/common/KVPair.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 org.apache.hugegraph.pd.common;

import java.io.Serializable;
import java.util.Objects;

public class KVPair<K, V> implements Serializable {

    /**
     * Key of this <code>Pair</code>.
     */
    private K key;
    /**
     * Value of this this <code>Pair</code>.
     */
    private V value;

    /**
     * Creates a new pair
     *
     * @param key   The key for this pair
     * @param value The value to use for this pair
     */
    public KVPair(K key, V value) {
        this.key = key;
        this.value = value;
    }

    /**
     * Gets the key for this pair.
     *
     * @return key for this pair
     */
    public K getKey() {
        return key;
    }

    public void setKey(K key) {
        this.key = key;
    }

    /**
     * Gets the value for this pair.
     *
     * @return value for this pair
     */
    public V getValue() {
        return value;
    }

    public void setValue(V value) {
        this.value = value;
    }

    /**
     * <p><code>String</code> representation of this
     * <code>Pair</code>.</p>
     *
     * <p>The default name/value delimiter '=' is always used.</p>
     *
     * @return <code>String</code> representation of this <code>Pair</code>
     */
    @Override
    public String toString() {
        return key + "=" + value;
    }

    /**
     * <p>Generate a hash code for this <code>Pair</code>.</p>
     *
     * <p>The hash code is calculated using both the name and
     * the value of the <code>Pair</code>.</p>
     *
     * @return hash code for this <code>Pair</code>
     */
    @Override
    public int hashCode() {
        // name's hashCode is multiplied by an arbitrary prime number (13)
        // in order to make sure there is a difference in the hashCode between
        // these two parameters:
        //  name: a  value: aa
        //  name: aa value: a
        return key.hashCode() * 13 + (value == null ? 0 : value.hashCode());
    }

    /**
     * <p>Test this <code>Pair</code> for equality with another
     * <code>Object</code>.</p>
     *
     * <p>If the <code>Object</code> to be tested is not a
     * <code>Pair</code> or is <code>null</code>, then this method
     * returns <code>false</code>.</p>
     *
     * <p>Two <code>Pair</code>s are considered equal if and only if
     * both the names and values are equal.</p>
     *
     * @param o the <code>Object</code> to test for
     *          equality with this <code>Pair</code>
     * @return <code>true</code> if the given <code>Object</code> is
     * equal to this <code>Pair</code> else <code>false</code>
     */
    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o instanceof KVPair) {
            KVPair pair = (KVPair) o;
            if (!Objects.equals(key, pair.key)) {
                return false;
            }
            return Objects.equals(value, pair.value);
        }
        return false;
    }
}