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 org.apache.cassandra.hints;
  
  import java.util.concurrent.atomic.AtomicBoolean;
  
  /**
   * A simple dispatch trigger that's being run every 10 seconds.
   *
   * Goes through all hint stores and schedules for dispatch all the hints for hosts that are:
   * 1. Not currently scheduled for dispatch, and
   * 2. Either have some hint files, or an active hint writer, and
   * 3. Are live
   *
   * What does triggering a hints store for dispatch mean?
   * - If there are existing hint files, it means submitting them for dispatch;
   * - If there is an active writer, closing it, for the next run to pick it up.
   */
  final class HintsDispatchTrigger implements Runnable
  {
      private final HintsCatalog catalog;
      private final HintsWriteExecutor writeExecutor;
      private final HintsDispatchExecutor dispatchExecutor;
      private final AtomicBoolean isPaused;
  
      HintsDispatchTrigger(HintsCatalog catalog,
                           HintsWriteExecutor writeExecutor,
                           HintsDispatchExecutor dispatchExecutor,
                           AtomicBoolean isPaused)
      {
          this.catalog = catalog;
          this.writeExecutor = writeExecutor;
          this.dispatchExecutor = dispatchExecutor;
          this.isPaused = isPaused;
      }
  
      public void run()
      {
          if (isPaused.get())
              return;
  
          catalog.stores()
                 .filter(store -> !isScheduled(store))
                 .filter(HintsStore::isLive)
                 .filter(store -> store.isWriting() || store.hasFiles())
                 .forEach(this::schedule);
      }
  
      private void schedule(HintsStore store)
      {
          if (store.hasFiles())
              dispatchExecutor.dispatch(store);
  
          if (store.isWriting())
              writeExecutor.closeWriter(store);
      }
  
      private boolean isScheduled(HintsStore store)
      {
          return dispatchExecutor.isScheduled(store);
      }
  }
  