content: /*
   * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
   * (the "License"). You may not use this work except in compliance with the License, which is
   * available at www.apache.org/licenses/LICENSE-2.0
   *
   * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
   * either express or implied, as more fully set forth in the License.
   *
   * See the NOTICE file distributed with this work for information regarding copyright ownership.
   */
  
  package alluxio.multi.process;
  
  import alluxio.conf.PropertyKey;
  
  import com.google.common.base.Preconditions;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.Closeable;
  import java.io.File;
  import java.io.IOException;
  import java.util.Map;
  import javax.annotation.concurrent.ThreadSafe;
  
  /**
   * Class for running and interacting with an Alluxio worker in a separate process.
   */
  @ThreadSafe
  public class Worker implements Closeable {
    private static final Logger LOG = LoggerFactory.getLogger(Worker.class);
  
    private final File mLogsDir;
    private final Map<PropertyKey, Object> mProperties;
  
    private ExternalProcess mProcess;
  
    /**
     * @param logsDir log directory
     * @param properties alluxio properties
     */
    public Worker(File logsDir, Map<PropertyKey, Object> properties) throws IOException {
      mLogsDir = logsDir;
      mProperties = properties;
    }
  
    /**
     * Launches the worker process.
     */
    public synchronized void start() throws IOException {
      Preconditions.checkState(mProcess == null, "Worker is already running");
      mProcess = new ExternalProcess(mProperties, LimitedLifeWorkerProcess.class,
          new File(mLogsDir, "worker.out"));
      mProcess.start();
    }
  
    @Override
    public synchronized void close() {
      if (mProcess != null) {
        mProcess.stop();
        mProcess = null;
      }
    }
  }
  