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.spark.examples;
  
  import org.apache.spark.SparkJobInfo;
  import org.apache.spark.SparkStageInfo;
  import org.apache.spark.api.java.JavaFutureAction;
  import org.apache.spark.api.java.JavaRDD;
  import org.apache.spark.api.java.JavaSparkContext;
  import org.apache.spark.api.java.function.Function;
  import org.apache.spark.sql.SparkSession;
  
  
  import java.util.Arrays;
  import java.util.List;
  
  /**
   * Example of using Spark's status APIs from Java.
   */
  public final class JavaStatusTrackerDemo {
  
    public static final String APP_NAME = "JavaStatusAPIDemo";
  
    public static final class IdentityWithDelay<T> implements Function<T, T> {
      @Override
      public T call(T x) throws Exception {
        Thread.sleep(2 * 1000);  // 2 seconds
        return x;
      }
    }
  
    public static void main(String[] args) throws Exception {
      SparkSession spark = SparkSession
        .builder()
        .appName(APP_NAME)
        .getOrCreate();
  
      final JavaSparkContext jsc = new JavaSparkContext(spark.sparkContext());
  
      // Example of implementing a progress reporter for a simple job.
      JavaRDD<Integer> rdd = jsc.parallelize(Arrays.asList(1, 2, 3, 4, 5), 5).map(
          new IdentityWithDelay<Integer>());
      JavaFutureAction<List<Integer>> jobFuture = rdd.collectAsync();
      while (!jobFuture.isDone()) {
        Thread.sleep(1000);  // 1 second
        List<Integer> jobIds = jobFuture.jobIds();
        if (jobIds.isEmpty()) {
          continue;
        }
        int currentJobId = jobIds.get(jobIds.size() - 1);
        SparkJobInfo jobInfo = jsc.statusTracker().getJobInfo(currentJobId);
        SparkStageInfo stageInfo = jsc.statusTracker().getStageInfo(jobInfo.stageIds()[0]);
        System.out.println(stageInfo.numTasks() + " tasks total: " + stageInfo.numActiveTasks() +
            " active, " + stageInfo.numCompletedTasks() + " complete");
      }
  
      System.out.println("Job results are: " + jobFuture.get());
      spark.stop();
    }
  }
  