com.ait.tooling.common.api.java.util.UUID Maven / Gradle / Ivy

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/*
   Copyright (c) 2014,2015,2016 Ahome' Innovation Technologies. 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.
 */

package com.ait.tooling.common.api.java.util;

public final class UUID
{    
    private static final char[] CHARS = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz".toCharArray();

    protected UUID()
    {
    }

    public static final String uuid()
    {
        final char[] uuid = new char[36];

        // rfc4122 requires these characters

        uuid[8] = uuid[13] = uuid[18] = uuid[23] = '-';

        uuid[14] = '4';

        // Fill in random data. At i==19 set the high bits of clock sequence as
        // per rfc4122, sec. 4.1.5

        for (int i = 0; i < 36; i++)
        {
            if (uuid[i] == 0)
            {
                final int r = (int) (Math.random() * 16);

                uuid[i] = CHARS[(i == 19) ? (r & 0x3) | 0x8 : r & 0xf];
            }
        }
        return new String(uuid);
    }
}