content: /*
   * 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.
   *
   * <p>These timestamps are used to order queries server-side, and resolve potential conflicts.
   */
  public interface TimestampGenerator extends AutoCloseable {
  
    /**
     * Returns the next timestamp, in <b>microseconds</b>.
     *
     * <p>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();
  }
  