com.landawn.abacus.util.Keyed Maven / Gradle / Ivy

Show more of this group Show more artifacts with this name
Show all versions of abacus-common Show documentation

A general programming library in Java/Android. It's easy to learn and simple to use with concise and powerful APIs.

There is a newer version: 5.2.4

/*
 * Copyright (C) 2017 HaiYang Li
 *
 * 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 com.landawn.abacus.util;

/**
 * It's designed for performance improvement by only hash/compare {@code key} in {@code hashCode/equals} method.
 *
 * @author HaiYang Li
 * @param  the key type
 * @param 
 * @see Wrapper
 */
@com.landawn.abacus.annotation.Immutable
public final class Keyed implements Immutable {

    private final K key;

    private final T val;

    Keyed(K key, T val) {
        this.key = key;
        this.val = val;
    }

    /**
     *
     * @param  the key type
     * @param 
     * @param key
     * @param val
     * @return
     */
    public static  Keyed of(final K key, final T val) {
        return new Keyed<>(key, val);
    }

    /**
     * 
     *
     * @return 
     */
    public K key() {
        return key;
    }

    /**
     * 
     *
     * @return 
     */
    public T val() {
        return val;
    }

    /**
     * 
     *
     * @return 
     */
    @Override
    public int hashCode() {
        return N.hashCode(key);
    }

    /**
     *
     * @param obj
     * @return
     */
    @Override
    public boolean equals(final Object obj) {
        return (obj == this) || (obj instanceof Keyed && N.equals(((Keyed) obj).key, key));
    }

    /**
     * 
     *
     * @return 
     */
    @Override
    public String toString() {
        return "{key=" + N.toString(key) + ", val=" + val + "}";
    }
}