Java ThreadLocalRandom random()

Description

Create a new random UUID.

License

Apache License

Return

the new UUID

Declaration

public static UUID random() 

Method Source Code

//package com.java2s;
/*//from w w  w  . j  ava  2 s.c o m
 * Copyright (c) 2011-2014 Pivotal Software, Inc.
 *
 *  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.
 */

import java.util.Random;
import java.util.UUID;

public class Main {
    private static boolean IS_THREADLOCALRANDOM_AVAILABLE = false;
    private static Random random;

    /**
     * Create a new random UUID.
     *
     * @return the new UUID
     */
    public static UUID random() {
        byte[] randomBytes = new byte[16];
        if (IS_THREADLOCALRANDOM_AVAILABLE) {
            java.util.concurrent.ThreadLocalRandom.current().nextBytes(randomBytes);
        } else {
            random.nextBytes(randomBytes);
        }

        long mostSigBits = 0;
        for (int i = 0; i < 8; i++) {
            mostSigBits = (mostSigBits << 8) | (randomBytes[i] & 0xff);
        }
        long leastSigBits = 0;
        for (int i = 8; i < 16; i++) {
            leastSigBits = (leastSigBits << 8) | (randomBytes[i] & 0xff);
        }

        return new UUID(mostSigBits, leastSigBits);
    }
}

Related

1. parseSeed(String seedString)
2. rand(final Collection items)
3. randInt(int min, int max)
4. random()
5. random()
6. random(char lower, char upper, int length)
7. random(double min, double max)
8. random(int min, int max)
9. random(T[] array)