org.graylog.util.uuid.ConcurrentUUID Maven / Gradle / Ivy
/*
* Copyright (C) 2020 Graylog, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* .
*/
/*
*
* Taken from
* https://github.com/Netflix/netflix-commons/blob/v0.3.0/netflix-commons-util/src/main/java/com/netflix/util/concurrent/ConcurrentUUIDFactory.java
*
* Original License:
*
* Copyright 2015 Netflix, 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.
*
*/
package org.graylog.util.uuid;
import java.util.Random;
import java.util.UUID;
import java.util.concurrent.ThreadLocalRandom;
public class ConcurrentUUID {
/**
* Generate a random UUID v4 that will perform reasonably when used by
* multiple threads under load.
*
* @see ConcurrentUUIDFactory
* @return random UUID
*/
public static UUID generateRandomUuid() {
final Random rnd = ThreadLocalRandom.current();
long mostSig = rnd.nextLong();
long leastSig = rnd.nextLong();
// Identify this as a version 4 UUID, that is one based on a random value.
mostSig &= 0xffffffffffff0fffL;
mostSig |= 0x0000000000004000L;
// Set the variant identifier as specified for version 4 UUID values. The two
// high order bits of the lower word are required to be one and zero, respectively.
leastSig &= 0x3fffffffffffffffL;
leastSig |= 0x8000000000000000L;
return new UUID(mostSig, leastSig);
}
}