com.datastax.driver.core.AtomicMonotonicTimestampGenerator Maven / Gradle / Ivy
/*
* Copyright DataStax, 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 com.datastax.driver.core;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;
/**
* A timestamp generator that guarantees monotonically increasing timestamps among all client
* threads, and logs warnings when timestamps drift in the future.
*
* @see AbstractMonotonicTimestampGenerator
*/
public class AtomicMonotonicTimestampGenerator extends LoggingMonotonicTimestampGenerator {
private AtomicLong lastRef = new AtomicLong(0);
/**
* Creates a new instance with a warning threshold and warning interval of one second.
*
* @see #AtomicMonotonicTimestampGenerator(long, TimeUnit, long, TimeUnit)
*/
public AtomicMonotonicTimestampGenerator() {
this(1, TimeUnit.SECONDS, 1, TimeUnit.SECONDS);
}
/**
* Creates a new instance.
*
* @param warningThreshold how far in the future timestamps are allowed to drift before a warning
* is logged.
* @param warningThresholdUnit the unit for {@code warningThreshold}.
* @param warningInterval how often the warning will be logged if timestamps keep drifting above
* the threshold.
* @param warningIntervalUnit the unit for {@code warningIntervalUnit}.
*/
public AtomicMonotonicTimestampGenerator(
long warningThreshold,
TimeUnit warningThresholdUnit,
long warningInterval,
TimeUnit warningIntervalUnit) {
super(warningThreshold, warningThresholdUnit, warningInterval, warningIntervalUnit);
}
@Override
public long next() {
while (true) {
long last = lastRef.get();
long next = computeNext(last);
if (lastRef.compareAndSet(last, next)) return next;
}
}
}