/* * 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(); }