Java Hash Calculate hash(Object v)

Description

hash

License

Apache License

Declaration

public static int hash(Object v) 

Method Source Code

//package com.java2s;
/*// w  ww  .j  a  v  a2s.co  m
 * 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.
 */

public class Main {
    public static int hash(Object v) {
        return v == null ? 0 : v.hashCode();
    }

    public static int hash(int h, boolean v) {
        return h * 31 + hashCode(v);
    }

    public static int hash(int h, byte v) {
        return h * 31 + v;
    }

    public static int hash(int h, char v) {
        return h * 31 + v;
    }

    public static int hash(int h, short v) {
        return h * 31 + v;
    }

    public static int hash(int h, int v) {
        return h * 31 + v;
    }

    public static int hash(int h, long v) {
        return h * 31 + hashCode(v);
    }

    public static int hash(int h, float v) {
        return hash(h, hashCode(v));
    }

    public static int hash(int h, double v) {
        return hash(h, hashCode(v));
    }

    public static int hash(int h, Object v) {
        return h * 31 + (v == null ? 1 : v.hashCode());
    }

    /** Computes the hash code of a {@code double} value. Equivalent to
     * {@link Double}{@code .hashCode(double)}, but that method was only
     * introduced in JDK 1.8.
     *
     * @param v Value
     * @return Hash code
     */
    public static int hashCode(double v) {
        long bits = Double.doubleToLongBits(v);
        return hashCode(bits);
    }

    /** Computes the hash code of a {@code float} value. Equivalent to
     * {@link Float}{@code .hashCode(float)}, but that method was only
     * introduced in JDK 1.8.
     *
     * @param v Value
     * @return Hash code
     */
    public static int hashCode(float v) {
        return Float.floatToIntBits(v);
    }

    /** Computes the hash code of a {@code long} value. Equivalent to
     * {@link Long}{@code .hashCode(long)}, but that method was only
     * introduced in JDK 1.8.
     *
     * @param v Value
     * @return Hash code
     */
    public static int hashCode(long v) {
        return (int) (v ^ (v >>> 32));
    }

    /** Computes the hash code of a {@code boolean} value. Equivalent to
     * {@link Boolean}{@code .hashCode(boolean)}, but that method was only
     * introduced in JDK 1.8.
     *
     * @param v Value
     * @return Hash code
     */
    public static int hashCode(boolean v) {
        return v ? 1231 : 1237;
    }
}

Related

1. hash(Object o)
2. hash(Object obj)
3. hash(Object obj)
4. hash(Object obj)
5. hash(Object object)
6. hash(Object value)
7. hash(Object value, int seed)
8. hash(Object... as)
9. hash(Object... value)