com.datastax.oss.driver.internal.core.time.ThreadLocalTimestampGenerator 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.shaded.guava.common.annotations.VisibleForTesting;
import net.jcip.annotations.ThreadSafe;
/**
* A timestamp generator that guarantees monotonically increasing timestamps within each thread, and
* logs warnings when timestamps drift in the future.
*
* Beware that there is a risk of timestamp collision with this generator when accessed by more
* than one thread at a time; only use it when threads are not in direct competition for timestamp
* ties (i.e., they are executing independent statements).
*
*
To activate this generator, modify the {@code advanced.timestamp-generator} section in the
* driver configuration, for example:
*
*
* datastax-java-driver {
* advanced.timestamp-generator {
* class = ThreadLocalTimestampGenerator
* 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 ThreadLocalTimestampGenerator extends MonotonicTimestampGenerator {
private final ThreadLocal lastRef = ThreadLocal.withInitial(() -> 0L);
public ThreadLocalTimestampGenerator(DriverContext context) {
super(context);
}
@VisibleForTesting
ThreadLocalTimestampGenerator(Clock clock, DriverContext context) {
super(clock, context);
}
@Override
public long next() {
Long last = this.lastRef.get();
long next = computeNext(last);
this.lastRef.set(next);
return next;
}
}