/*
 * ====================================================================
 * 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */

package org.apache.http.util;

A set of utility methods to help produce consistent equals and hashCode methods. 
Since:
4.0/**
 * A set of utility methods to help produce consistent
 * {@link Object#equals equals} and {@link Object#hashCode hashCode} methods.
 *
 *
 * @since 4.0
 */
public final class LangUtils {

    public static final int HASH_SEED = 17;
    public static final int HASH_OFFSET = 37;

    
Disabled default constructor. /** Disabled default constructor. */
    private LangUtils() {
    }

    public static int hashCode(final int seed, final int hashcode) {
        return seed * HASH_OFFSET + hashcode;
    }

    public static int hashCode(final int seed, final boolean b) {
        return hashCode(seed, b ? 1 : 0);
    }

    public static int hashCode(final int seed, final Object obj) {
        return hashCode(seed, obj != null ? obj.hashCode() : 0);
    }

    
Check if two objects are equal.
Params:
obj1 – first object to compare, may be null
obj2 – second object to compare, may be null
Returns:
true if the objects are equal or both null/**
     * Check if two objects are equal.
     *
     * @param obj1 first object to compare, may be {@code null}
     * @param obj2 second object to compare, may be {@code null}
     * @return {@code true} if the objects are equal or both null
     */
    public static boolean equals(final Object obj1, final Object obj2) {
        return obj1 == null ? obj2 == null : obj1.equals(obj2);
    }

    
Check if two object arrays are equal.

If both parameters are null, return true
If one parameter is null, return false
If the array lengths are different, return false
Compare array elements using .equals(); return false if any comparisons fail.
Return true

Params:
a1 – first array to compare, may be null
a2 – second array to compare, may be null
Returns:
true if the arrays are equal or both null/**
     * Check if two object arrays are equal.
     * <ul>
     * <li>If both parameters are null, return {@code true}</li>
     * <li>If one parameter is null, return {@code false}</li>
     * <li>If the array lengths are different, return {@code false}</li>
     * <li>Compare array elements using .equals(); return {@code false} if any comparisons fail.</li>
     * <li>Return {@code true}</li>
     * </ul>
     *
     * @param a1 first array to compare, may be {@code null}
     * @param a2 second array to compare, may be {@code null}
     * @return {@code true} if the arrays are equal or both null
     */
    public static boolean equals(final Object[] a1, final Object[] a2) {
        if (a1 == null) {
            return a2 == null;
        }
        if (a2 != null && a1.length == a2.length) {
            for (int i = 0; i < a1.length; i++) {
                if (!equals(a1[i], a2[i])) {
                    return false;
                }
            }
            return true;
        }
        return false;
    }

}