/**
    *
    * 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.hadoop.hbase.regionserver.handler;
  
  import java.io.IOException;
  import java.util.concurrent.atomic.AtomicInteger;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.Server;
  import org.apache.hadoop.hbase.ServerName;
  import org.apache.hadoop.hbase.SplitLogCounters;
  import org.apache.hadoop.hbase.SplitLogTask;
  import org.apache.hadoop.hbase.coordination.SplitLogWorkerCoordination;
  import org.apache.hadoop.hbase.executor.EventHandler;
  import org.apache.hadoop.hbase.executor.EventType;
  import org.apache.hadoop.hbase.protobuf.generated.ZooKeeperProtos.SplitLogTask.RecoveryMode;
  import org.apache.hadoop.hbase.regionserver.SplitLogWorker.TaskExecutor;
  import org.apache.hadoop.hbase.regionserver.SplitLogWorker.TaskExecutor.Status;
  import org.apache.hadoop.hbase.util.CancelableProgressable;
  
  /**
   * Handles log splitting a wal
   */
  @InterfaceAudience.Private
  public class WALSplitterHandler extends EventHandler {
    private static final Log LOG = LogFactory.getLog(WALSplitterHandler.class);
    private final ServerName serverName;
    private final CancelableProgressable reporter;
    private final AtomicInteger inProgressTasks;
    private final TaskExecutor splitTaskExecutor;
    private final RecoveryMode mode;
    private final SplitLogWorkerCoordination.SplitTaskDetails splitTaskDetails;
    private final SplitLogWorkerCoordination coordination;
  
  
    public WALSplitterHandler(final Server server, SplitLogWorkerCoordination coordination,
        SplitLogWorkerCoordination.SplitTaskDetails splitDetails, CancelableProgressable reporter,
        AtomicInteger inProgressTasks, TaskExecutor splitTaskExecutor, RecoveryMode mode) {
      super(server, EventType.RS_LOG_REPLAY);
      this.splitTaskDetails = splitDetails;
      this.coordination = coordination;
      this.reporter = reporter;
      this.inProgressTasks = inProgressTasks;
      this.inProgressTasks.incrementAndGet();
      this.serverName = server.getServerName();
      this.splitTaskExecutor = splitTaskExecutor;
      this.mode = mode;
    }
  
    @Override
    public void process() throws IOException {
      long startTime = System.currentTimeMillis();
      try {
        Status status = this.splitTaskExecutor.exec(splitTaskDetails.getWALFile(), mode, reporter);
        switch (status) {
        case DONE:
          coordination.endTask(new SplitLogTask.Done(this.serverName,this.mode),
            SplitLogCounters.tot_wkr_task_done, splitTaskDetails);
          break;
        case PREEMPTED:
          SplitLogCounters.tot_wkr_preempt_task.incrementAndGet();
          LOG.warn("task execution prempted " + splitTaskDetails.getWALFile());
          break;
        case ERR:
          if (server != null && !server.isStopped()) {
            coordination.endTask(new SplitLogTask.Err(this.serverName, this.mode),
              SplitLogCounters.tot_wkr_task_err, splitTaskDetails);
            break;
          }
          // if the RS is exiting then there is probably a tons of stuff
          // that can go wrong. Resign instead of signaling error.
          //$FALL-THROUGH$
        case RESIGNED:
          if (server != null && server.isStopped()) {
            LOG.info("task execution interrupted because worker is exiting "
                + splitTaskDetails.toString());
          }
          coordination.endTask(new SplitLogTask.Resigned(this.serverName, this.mode),
            SplitLogCounters.tot_wkr_task_resigned, splitTaskDetails);
          break;
        }
     } finally {
       LOG.info("worker " + serverName + " done with task " + splitTaskDetails.toString() + " in "
           + (System.currentTimeMillis() - startTime) + "ms");
       this.inProgressTasks.decrementAndGet();
     }
   }
 }