/*
* Copyright (C) 2012-2015 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;
/**
* Generates client-side, microsecond-precision query timestamps.
* <p/>
* Given that Cassandra uses those timestamps to resolve conflicts, implementations should generate
* monotonically increasing timestamps for successive invocations of {@link #next()}.
*/
public interface TimestampGenerator {
/**
* Returns the next timestamp.
* <p/>
* Implementors should enforce increasing monotonicity of timestamps, that is,
* a timestamp returned should always be strictly greater that any previously returned
* timestamp.
* <p/>
* Implementors should strive to achieve microsecond precision in the best possible way,
* which is usually largely dependent on the underlying operating system's capabilities.
*
* @return the next timestamp (in microseconds). If it equals {@link Long#MIN_VALUE}, it won't be
* sent by the driver, letting Cassandra generate a server-side timestamp.
*/
long next();
}