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.master.file.mdsync;
  
  import alluxio.annotation.SuppressFBWarnings;
  import alluxio.exception.runtime.DeadlineExceededRuntimeException;
  import alluxio.grpc.SyncMetadataTask;
  
  import com.google.common.base.Preconditions;
  import com.google.common.base.Stopwatch;
  
  import java.util.Arrays;
  import java.util.concurrent.TimeUnit;
  import java.util.stream.Stream;
  
  /**
   * A TaskGroup represents a set of {@link BaseTask} objects.
   */
  public class TaskGroup {
    @SuppressFBWarnings(value = "EI_EXPOSE_REP2")
    private final BaseTask[] mTasks;
    private final long mGroupId;
  
    /**
     * Creates a new task group.
     * @param groupId the id for this task group
     * @param tasks the tasks to group
     */
    public TaskGroup(long groupId, BaseTask... tasks) {
      Preconditions.checkState(tasks != null && tasks.length > 0);
      mGroupId = groupId;
      mTasks = tasks;
    }
  
    /**
     * @return the base task for this group
     */
    public BaseTask getBaseTask() {
      return mTasks[0];
    }
  
    /**
     * @return a stream of the tasks
     */
    public Stream<BaseTask> getTasks() {
      return Arrays.stream(mTasks);
    }
  
    /**
     * @return the task count
     */
    public int getTaskCount() {
      return mTasks.length;
    }
  
    /**
     * @return true if all tasks succeeded
     */
    public boolean allSucceeded() {
      return Arrays.stream(mTasks).allMatch(BaseTask::succeeded);
    }
  
    /**
     * @return a stream of the tasks in protobuf format
     */
    public Stream<SyncMetadataTask> toProtoTasks() {
      return getTasks().map(BaseTask::toProtoTask);
    }
  
    /**
     * @return the unique group id for this task
     */
    public long getGroupId() {
      return mGroupId;
    }
  
    /**
     * Waits for all the tasks to complete or until
     * a timeout occurs. If any tasks fail it will throw the
     * error caused by the failed task.
     * If the wait times-out a {@link DeadlineExceededRuntimeException} is thrown.
     * @param timeoutMs the time in milliseconds to wait for the task
     *                  to complete, or 0 to wait forever
     */
    public void waitAllComplete(long timeoutMs) throws Throwable {
      Stopwatch sw = Stopwatch.createStarted();
      for (BaseTask task : mTasks) {
        task.waitComplete(getRemainingTime(sw, timeoutMs));
      }
    }
  
    private static long getRemainingTime(
        Stopwatch sw, long timeoutMs) throws DeadlineExceededRuntimeException {
      // Endless wait
      if (timeoutMs == 0) {
        return 0;
      }
      long remaining = timeoutMs - sw.elapsed(TimeUnit.MILLISECONDS);
      if (remaining <= 0) {
        throw new DeadlineExceededRuntimeException("Task still running.");
      }
      return remaining;
    }
  }
  