Java Hash Code Calculate hashCode(Object o)

Description

hash Code

License

Open Source License

Declaration

public static int hashCode(Object o) 

Method Source Code

//package com.java2s;
/*/*from ww  w .  j  a  v a  2 s .  c  o  m*/
 * Copyright (c) 2007, 2011-2013, 2015, 2016 Eike Stepper (Berlin, Germany) and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    Eike Stepper - initial API and implementation
 *    Christian W. Damus (CEA LIST) - bug 418454
 */

public class Main {
    public static int hashCode(Object o) {
        if (o == null) {
            return 0;
        }

        return o.hashCode();
    }

    /**
     * A collision-free hash code for small sets (<=4) of small, positive integers (<=128)
     *
     * @since 3.2
     */
    public static int hashCode(int... values) {
        int hash = 0;
        for (int i = 0; i < values.length; i++) {
            hash += values[i];
            hash = (hash << 7) - hash;
        }

        return hash;
    }

    public static int hashCode(long num) {
        return (int) (num >> 32) ^ (int) (num & 0xffffffff);
    }
}

Related

1. hashCode(long[] a, int fromIndex, int toIndex)
2. hashCode(Object a)
3. hashCode(Object array)
4. hashCode(Object o)
5. hashCode(Object o)
6. hashCode(Object o1, Object o2)
7. hashCode(Object obj)
8. hashCode(Object obj)
9. hashcode(Object obj)