Java Hash Code Calculate hashCode(Object obj)

Description

hash Code

License

Open Source License

Declaration

public static int hashCode(Object obj) 

Method Source Code

//package com.java2s;
/*// w ww.ja va2 s .  c o  m
* Copyright (c) 2015, Alachisoft. All Rights Reserved.
*
* 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.
*/

public class Main {
    public static int hashCode(Object obj) {
        if (obj instanceof String) {
            char[] array = ((String) obj).toCharArray();
            int[] intArray = new int[(int) Math.ceil((double) (array.length) / 2)];

            for (int i = 0, j = 0; i < intArray.length; i++) {
                char[] toInt = new char[2];
                if (j < array.length) {
                    toInt[0] = array[j++];
                }
                if (j < array.length) {
                    toInt[1] = array[j++];
                }
                intArray[i] = charToInt(toInt);
            }

            int num = 0x15051505;
            int num2 = num;

            for (int i = array.length, j = 0; i > 0; i -= 4, j += 2) {

                num = (((num << 5) + num) + (num >> 0x1b)) ^ intArray[j];
                if (i <= 2) {
                    break;
                }
                num2 = (((num2 << 5) + num2) + (num2 >> 0x1b)) ^ intArray[j + 1];
            }
            return (num + (num2 * 0x5d588b65));
        } else
            return obj.hashCode();
    }

    private static int charToInt(char[] array) {
        return (array[0] | (array[1] << 16));
    }
}

Related

1. hashCode(Object obj)
2. hashcode(Object obj)
3. hashCode(Object obj)
4. hashCode(Object obj)
5. hashCode(Object obj)
6. hashCode(Object object)
7. hashCode(Object object)
8. hashCode(Object object)
9. hashCode(Object object)