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.internal.core.specex;
  
  import com.datastax.oss.driver.api.core.CqlIdentifier;
  import com.datastax.oss.driver.api.core.context.DriverContext;
  import com.datastax.oss.driver.api.core.metadata.Node;
  import com.datastax.oss.driver.api.core.session.Request;
  import com.datastax.oss.driver.api.core.specex.SpeculativeExecutionPolicy;
  import edu.umd.cs.findbugs.annotations.NonNull;
  import edu.umd.cs.findbugs.annotations.Nullable;
  import net.jcip.annotations.ThreadSafe;
  
  /**
   * A policy that never triggers speculative executions.
   *
   * <p>To activate this policy, modify the {@code advanced.speculative-execution-policy} section in
   * the driver configuration, for example:
   *
   * <pre>
   * datastax-java-driver {
   *   advanced.speculative-execution-policy {
   *     class = NoSpeculativeExecutionPolicy
   *   }
   * }
   * </pre>
   *
   * See {@code reference.conf} (in the manual or core driver JAR) for more details.
   */
  @ThreadSafe
  public class NoSpeculativeExecutionPolicy implements SpeculativeExecutionPolicy {
  
    public NoSpeculativeExecutionPolicy(
        @SuppressWarnings("unused") DriverContext context,
        @SuppressWarnings("unused") String profileName) {
      // nothing to do
    }
  
    @Override
    @SuppressWarnings("unused")
    public long nextExecution(
        @NonNull Node node,
        @Nullable CqlIdentifier keyspace,
        @NonNull Request request,
        int runningExecutions) {
      // never start speculative executions
      return -1;
    }
  
    @Override
    public void close() {
      // nothing to do
    }
  }
  