Java Hash Calculate hash(int base, boolean field)

Description

Retrieves a unique hash value for the specified field, based on the specified base value.

License

Open Source License

Parameter

Parameter	Description
base	The value on which to base the hash value.
field	The field which to retrieve a hash value.

Return

A hash value for the specified field.

Declaration

public static int hash(int base, boolean field) 

Method Source Code

//package com.java2s;
/******************************************************************************
 * Copyright (c) 2002, 2004 IBM Corporation 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://from   w  w  w  . ja  v a  2s. c  om
 *    IBM Corporation - initial API and implementation 
 ****************************************************************************/

public class Main {
    /**
     * An arbitrary constant non-zero value.
     */
    protected static final int CONSTANT = 17;
    /**
     * An odd prime.
     */
    protected static final int PRIME = 37;

    /**
     * Retrieves a unique hash value for the specified field, based on the
     * specified base value.
     * 
     * @return A hash value for the specified field.
     * @param base
     *            The value on which to base the hash value.
     * @param field
     *            The field which to retrieve a hash value.
     */
    public static int hash(int base, boolean field) {
        return PRIME * base + (field ? 0 : 1);
    }

    /**
     * Retrieves a unique hash value for the specified field, based on a
     * constant base value.
     * 
     * @return A hash value for the specified field.
     * @param field
     *            The field which to retrieve a hash value.
     */
    public static int hash(boolean field) {
        return hash(CONSTANT, field);
    }

    /**
     * Retrieves a unique hash value for the specified field, based on the
     * specified base value.
     * 
     * @return A hash value for the specified field.
     * @param base
     *            The value on which to base the hash value.
     * @param field
     *            The field which to retrieve a hash value.
     */
    public static int hash(int base, byte field) {
        return PRIME * base + field;
    }

    /**
     * Retrieves a unique hash value for the specified field, based on a
     * constant base value.
     * 
     * @return A hash value for the specified field.
     * @param field
     *            The field which to retrieve a hash value.
     */
    public static int hash(byte field) {
        return hash(CONSTANT, field);
    }

    /**
     * Retrieves a unique hash value for the specified field, based on the
     * specified base value.
     * 
     * @return A hash value for the specified field.
     * @param base
     *            The value on which to base the hash value.
     * @param field
     *            The field which to retrieve a hash value.
     */
    public static int hash(int base, char field) {
        return PRIME * base + field;
    }

    /**
     * Retrieves a unique hash value for the specified field, based on a
     * constant base value.
     * 
     * @return A hash value for the specified field.
     * @param field
     *            The field which to retrieve a hash value.
     */
    public static int hash(char field) {
        return hash(CONSTANT, field);
    }

    /**
     * Retrieves a unique hash value for the specified field, based on the
     * specified base value.
     * 
     * @return A hash value for the specified field.
     * @param base
     *            The value on which to base the hash value.
     * @param field
     *            The field which to retrieve a hash value.
     */
    public static int hash(int base, short field) {
        return PRIME * base + field;
    }

    /**
     * Retrieves a unique hash value for the specified field, based on a
     * constant base value.
     * 
     * @return A hash value for the specified field.
     * @param field
     *            The field which to retrieve a hash value.
     */
    public static int hash(short field) {
        return hash(CONSTANT, field);
    }

    /**
     * Retrieves a unique hash value for the specified field, based on the
     * specified base value.
     * 
     * @return A hash value for the specified field.
     * @param base
     *            The value on which to base the hash value.
     * @param field
     *            The field which to retrieve a hash value.
     */
    public static int hash(int base, int field) {
        return PRIME * base + field;
    }

    /**
     * Retrieves a unique hash value for the specified field, based on a
     * constant base value.
     * 
     * @return A hash value for the specified field.
     * @param field
     *            The field which to retrieve a hash value.
     */
    public static int hash(int field) {
        return hash(CONSTANT, field);
    }

    /**
     * Retrieves a unique hash value for the specified field, based on the
     * specified base value.
     * 
     * @return A hash value for the specified field.
     * @param base
     *            The value on which to base the hash value.
     * @param field
     *            The field which to retrieve a hash value.
     */
    public static int hash(int base, long field) {
        return PRIME * base + (int) (field ^ (field >>> 32));
    }

    /**
     * Retrieves a unique hash value for the specified field, based on a
     * constant base value.
     * 
     * @return A hash value for the specified field.
     * @param field
     *            The field which to retrieve a hash value.
     */
    public static int hash(long field) {
        return hash(CONSTANT, field);
    }

    /**
     * Retrieves a unique hash value for the specified field, based on the
     * specified base value.
     * 
     * @return A hash value for the specified field.
     * @param base
     *            The value on which to base the hash value.
     * @param field
     *            The field which to retrieve a hash value.
     */
    public static int hash(int base, float field) {
        return PRIME * base + Float.floatToIntBits(field);
    }

    /**
     * Retrieves a unique hash value for the specified field, based on a
     * constant base value.
     * 
     * @return A hash value for the specified field.
     * @param field
     *            The field which to retrieve a hash value.
     */
    public static int hash(float field) {
        return hash(CONSTANT, field);
    }

    /**
     * Retrieves a unique hash value for the specified field, based on the
     * specified base value.
     * 
     * @return A hash value for the specified field.
     * @param base
     *            The value on which to base the hash value.
     * @param field
     *            The field which to retrieve a hash value.
     */
    public static int hash(int base, double field) {
        return hash(base, Double.doubleToLongBits(field));
    }

    /**
     * Retrieves a unique hash value for the specified field, based on a
     * constant base value.
     * 
     * @return A hash value for the specified field.
     * @param field
     *            The field which to retrieve a hash value.
     */
    public static int hash(double field) {
        return hash(CONSTANT, field);
    }

    /**
     * Retrieves a unique hash value for the specified object, based on the
     * specified base value.
     * 
     * @return A hash value for the specified object.
     * @param base
     *            The value on which to base the hash value.
     * @param object
     *            The object for which to retrieve a hash value.
     */
    public static int hash(int base, Object object) {
        return PRIME * base + (null == object ? 0 : object.hashCode());
    }

    /**
     * Retrieves a unique hash value for the specified object, based on a
     * constant base value.
     * 
     * @return A hash value for the specified object.
     * @param object
     *            The object for which to retrieve a hash value.
     */
    public static int hash(Object object) {
        return hash(CONSTANT, object);
    }
}

Related

1. hash(final Object object)
2. hash(final Object[] objects)
3. hash(finalObject object)
4. hash(int aSeed, boolean aBoolean)
5. hash(int aSeed, Object[] aArray)
6. hash(int h)
7. hash(int h)
8. hash(int h, boolean v)
9. hash(int h, Object o)