com.datastax.oss.driver.internal.core.time.AtomicTimestampGenerator Maven / Gradle / Ivy
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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.oss.driver.internal.core.time;
import com.datastax.oss.driver.api.core.context.DriverContext;
import com.datastax.oss.driver.internal.core.context.InternalDriverContext;
import com.datastax.oss.driver.shaded.guava.common.annotations.VisibleForTesting;
import java.util.concurrent.atomic.AtomicLong;
import net.jcip.annotations.ThreadSafe;
/**
* A timestamp generator that guarantees monotonically increasing timestamps across all client
* threads, and logs warnings when timestamps drift in the future.
*
* To activate this generator, modify the {@code advanced.timestamp-generator} section in the
* driver configuration, for example:
*
*
* datastax-java-driver {
* advanced.timestamp-generator {
* class = AtomicTimestampGenerator
* drift-warning {
* threshold = 1 second
* interval = 10 seconds
* }
* force-java-clock = false
* }
* }
*
*
* See {@code reference.conf} (in the manual or core driver JAR) for more details.
*/
@ThreadSafe
public class AtomicTimestampGenerator extends MonotonicTimestampGenerator {
private final AtomicLong lastRef = new AtomicLong(0);
public AtomicTimestampGenerator(DriverContext context) {
super(context);
}
@VisibleForTesting
AtomicTimestampGenerator(Clock clock, InternalDriverContext context) {
super(clock, context);
}
@Override
public long next() {
while (true) {
long last = lastRef.get();
long next = computeNext(last);
if (lastRef.compareAndSet(last, next)) {
return next;
}
}
}
}