com.datastax.oss.driver.api.core.time.TimestampGenerator Maven / Gradle / Ivy
/*
* 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.api.core.time;
import com.datastax.oss.driver.api.core.cql.Statement;
/**
* Generates client-side, microsecond-precision query timestamps.
*
* These timestamps are used to order queries server-side, and resolve potential conflicts.
*/
public interface TimestampGenerator extends AutoCloseable {
/**
* Returns the next timestamp, in microseconds.
*
*
The timestamps returned by this method should be monotonic; that is, successive invocations
* should return strictly increasing results. Note that this might not be possible using the clock
* alone, if it is not precise enough; alternative strategies might include incrementing the last
* returned value if the clock tick hasn't changed, and possibly drifting in the future. See the
* built-in driver implementations for more details.
*
* @return the next timestamp, or {@link Statement#NO_DEFAULT_TIMESTAMP} to indicate that the
* driver should not send one with the query (and let Cassandra generate a server-side
* timestamp).
*/
long next();
}