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.streaming;
  
  import java.io.*;
  import java.nio.charset.StandardCharsets;
  import java.util.*;
  import java.util.concurrent.atomic.AtomicBoolean;
  
  import scala.Tuple2;
  
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.io.LongWritable;
  import org.apache.hadoop.io.Text;
  import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
  
  import org.junit.Assert;
  import org.junit.Test;
  
  import com.google.common.io.Files;
  import com.google.common.collect.Sets;
  
  import org.apache.spark.HashPartitioner;
  import org.apache.spark.SparkConf;
  import org.apache.spark.api.java.JavaPairRDD;
  import org.apache.spark.api.java.JavaRDD;
  import org.apache.spark.api.java.JavaSparkContext;
  import org.apache.spark.api.java.Optional;
  import org.apache.spark.api.java.function.*;
  import org.apache.spark.storage.StorageLevel;
  import org.apache.spark.streaming.api.java.*;
  import org.apache.spark.util.LongAccumulator;
  import org.apache.spark.util.Utils;
  
  // The test suite itself is Serializable so that anonymous Function implementations can be
  // serialized, as an alternative to converting these anonymous classes to static inner classes;
  // see http://stackoverflow.com/questions/758570/.
  public class JavaAPISuite extends LocalJavaStreamingContext implements Serializable {
  
    public static void equalIterator(Iterator<?> a, Iterator<?> b) {
      while (a.hasNext() && b.hasNext()) {
        Assert.assertEquals(a.next(), b.next());
      }
      Assert.assertEquals(a.hasNext(), b.hasNext());
    }
  
    public static void equalIterable(Iterable<?> a, Iterable<?> b) {
        equalIterator(a.iterator(), b.iterator());
    }
  
    @Test
    public void testInitialization() {
      Assert.assertNotNull(ssc.sparkContext());
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testContextState() {
      List<List<Integer>> inputData = Arrays.asList(Arrays.asList(1, 2, 3, 4));
      Assert.assertEquals(StreamingContextState.INITIALIZED, ssc.getState());
      JavaDStream<Integer> stream = JavaTestUtils.attachTestInputStream(ssc, inputData, 1);
      JavaTestUtils.attachTestOutputStream(stream);
      Assert.assertEquals(StreamingContextState.INITIALIZED, ssc.getState());
      ssc.start();
      Assert.assertEquals(StreamingContextState.ACTIVE, ssc.getState());
      ssc.stop();
      Assert.assertEquals(StreamingContextState.STOPPED, ssc.getState());
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testCount() {
      List<List<Integer>> inputData = Arrays.asList(
          Arrays.asList(1,2,3,4),
          Arrays.asList(3,4,5),
          Arrays.asList(3));
  
      List<List<Long>> expected = Arrays.asList(
          Arrays.asList(4L),
          Arrays.asList(3L),
          Arrays.asList(1L));
  
      JavaDStream<Integer> stream = JavaTestUtils.attachTestInputStream(ssc, inputData, 1);
      JavaDStream<Long> count = stream.count();
      JavaTestUtils.attachTestOutputStream(count);
      List<List<Long>> result = JavaTestUtils.runStreams(ssc, 3, 3);
      assertOrderInvariantEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testMap() {
      List<List<String>> inputData = Arrays.asList(
          Arrays.asList("hello", "world"),
          Arrays.asList("goodnight", "moon"));
  
      List<List<Integer>> expected = Arrays.asList(
          Arrays.asList(5,5),
          Arrays.asList(9,4));
  
      JavaDStream<String> stream = JavaTestUtils.attachTestInputStream(ssc, inputData, 1);
      JavaDStream<Integer> letterCount = stream.map(new Function<String, Integer>() {
          @Override
          public Integer call(String s) {
            return s.length();
          }
      });
      JavaTestUtils.attachTestOutputStream(letterCount);
      List<List<Integer>> result = JavaTestUtils.runStreams(ssc, 2, 2);
  
      assertOrderInvariantEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testWindow() {
      List<List<Integer>> inputData = Arrays.asList(
          Arrays.asList(1,2,3),
          Arrays.asList(4,5,6),
          Arrays.asList(7,8,9));
  
      List<List<Integer>> expected = Arrays.asList(
          Arrays.asList(1,2,3),
          Arrays.asList(4,5,6,1,2,3),
          Arrays.asList(7,8,9,4,5,6),
          Arrays.asList(7,8,9));
  
      JavaDStream<Integer> stream = JavaTestUtils.attachTestInputStream(ssc, inputData, 1);
      JavaDStream<Integer> windowed = stream.window(new Duration(2000));
      JavaTestUtils.attachTestOutputStream(windowed);
      List<List<Integer>> result = JavaTestUtils.runStreams(ssc, 4, 4);
  
      assertOrderInvariantEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testWindowWithSlideDuration() {
      List<List<Integer>> inputData = Arrays.asList(
          Arrays.asList(1,2,3),
          Arrays.asList(4,5,6),
          Arrays.asList(7,8,9),
          Arrays.asList(10,11,12),
          Arrays.asList(13,14,15),
          Arrays.asList(16,17,18));
  
      List<List<Integer>> expected = Arrays.asList(
          Arrays.asList(1,2,3,4,5,6),
          Arrays.asList(1,2,3,4,5,6,7,8,9,10,11,12),
          Arrays.asList(7,8,9,10,11,12,13,14,15,16,17,18),
          Arrays.asList(13,14,15,16,17,18));
  
      JavaDStream<Integer> stream = JavaTestUtils.attachTestInputStream(ssc, inputData, 1);
      JavaDStream<Integer> windowed = stream.window(new Duration(4000), new Duration(2000));
      JavaTestUtils.attachTestOutputStream(windowed);
      List<List<Integer>> result = JavaTestUtils.runStreams(ssc, 8, 4);
  
      assertOrderInvariantEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testFilter() {
      List<List<String>> inputData = Arrays.asList(
          Arrays.asList("giants", "dodgers"),
          Arrays.asList("yankees", "red sox"));
  
      List<List<String>> expected = Arrays.asList(
          Arrays.asList("giants"),
          Arrays.asList("yankees"));
  
      JavaDStream<String> stream = JavaTestUtils.attachTestInputStream(ssc, inputData, 1);
      JavaDStream<String> filtered = stream.filter(new Function<String, Boolean>() {
        @Override
        public Boolean call(String s) {
          return s.contains("a");
        }
      });
      JavaTestUtils.attachTestOutputStream(filtered);
      List<List<String>> result = JavaTestUtils.runStreams(ssc, 2, 2);
  
      assertOrderInvariantEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testRepartitionMorePartitions() {
      List<List<Integer>> inputData = Arrays.asList(
        Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10),
        Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10));
      JavaDStream<Integer> stream =
          JavaTestUtils.attachTestInputStream(ssc, inputData, 2);
      JavaDStreamLike<Integer,JavaDStream<Integer>,JavaRDD<Integer>> repartitioned =
          stream.repartition(4);
      JavaTestUtils.attachTestOutputStream(repartitioned);
      List<List<List<Integer>>> result = JavaTestUtils.runStreamsWithPartitions(ssc, 2, 2);
      Assert.assertEquals(2, result.size());
      for (List<List<Integer>> rdd : result) {
        Assert.assertEquals(4, rdd.size());
        Assert.assertEquals(
          10, rdd.get(0).size() + rdd.get(1).size() + rdd.get(2).size() + rdd.get(3).size());
      }
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testRepartitionFewerPartitions() {
      List<List<Integer>> inputData = Arrays.asList(
        Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10),
        Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10));
      JavaDStream<Integer> stream =
          JavaTestUtils.attachTestInputStream(ssc, inputData, 4);
      JavaDStreamLike<Integer,JavaDStream<Integer>,JavaRDD<Integer>> repartitioned =
          stream.repartition(2);
      JavaTestUtils.attachTestOutputStream(repartitioned);
      List<List<List<Integer>>> result = JavaTestUtils.runStreamsWithPartitions(ssc, 2, 2);
      Assert.assertEquals(2, result.size());
      for (List<List<Integer>> rdd : result) {
        Assert.assertEquals(2, rdd.size());
        Assert.assertEquals(10, rdd.get(0).size() + rdd.get(1).size());
      }
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testGlom() {
      List<List<String>> inputData = Arrays.asList(
          Arrays.asList("giants", "dodgers"),
          Arrays.asList("yankees", "red sox"));
  
      List<List<List<String>>> expected = Arrays.asList(
          Arrays.asList(Arrays.asList("giants", "dodgers")),
          Arrays.asList(Arrays.asList("yankees", "red sox")));
  
      JavaDStream<String> stream = JavaTestUtils.attachTestInputStream(ssc, inputData, 1);
      JavaDStream<List<String>> glommed = stream.glom();
      JavaTestUtils.attachTestOutputStream(glommed);
      List<List<List<String>>> result = JavaTestUtils.runStreams(ssc, 2, 2);
  
      Assert.assertEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testMapPartitions() {
      List<List<String>> inputData = Arrays.asList(
          Arrays.asList("giants", "dodgers"),
          Arrays.asList("yankees", "red sox"));
  
      List<List<String>> expected = Arrays.asList(
          Arrays.asList("GIANTSDODGERS"),
          Arrays.asList("YANKEESRED SOX"));
  
      JavaDStream<String> stream = JavaTestUtils.attachTestInputStream(ssc, inputData, 1);
      JavaDStream<String> mapped = stream.mapPartitions(
          new FlatMapFunction<Iterator<String>, String>() {
            @Override
            public Iterator<String> call(Iterator<String> in) {
              StringBuilder out = new StringBuilder();
              while (in.hasNext()) {
                out.append(in.next().toUpperCase(Locale.ENGLISH));
              }
              return Arrays.asList(out.toString()).iterator();
            }
          });
      JavaTestUtils.attachTestOutputStream(mapped);
      List<List<String>> result = JavaTestUtils.runStreams(ssc, 2, 2);
  
      Assert.assertEquals(expected, result);
    }
  
    private static class IntegerSum implements Function2<Integer, Integer, Integer> {
      @Override
      public Integer call(Integer i1, Integer i2) {
        return i1 + i2;
      }
    }
  
    private static class IntegerDifference implements Function2<Integer, Integer, Integer> {
      @Override
      public Integer call(Integer i1, Integer i2) {
        return i1 - i2;
      }
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testReduce() {
      List<List<Integer>> inputData = Arrays.asList(
          Arrays.asList(1,2,3),
          Arrays.asList(4,5,6),
          Arrays.asList(7,8,9));
  
      List<List<Integer>> expected = Arrays.asList(
          Arrays.asList(6),
          Arrays.asList(15),
          Arrays.asList(24));
  
      JavaDStream<Integer> stream = JavaTestUtils.attachTestInputStream(ssc, inputData, 1);
      JavaDStream<Integer> reduced = stream.reduce(new IntegerSum());
      JavaTestUtils.attachTestOutputStream(reduced);
      List<List<Integer>> result = JavaTestUtils.runStreams(ssc, 3, 3);
  
      Assert.assertEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testReduceByWindowWithInverse() {
      testReduceByWindow(true);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testReduceByWindowWithoutInverse() {
      testReduceByWindow(false);
    }
  
    @SuppressWarnings("unchecked")
    private void testReduceByWindow(boolean withInverse) {
      List<List<Integer>> inputData = Arrays.asList(
          Arrays.asList(1,2,3),
          Arrays.asList(4,5,6),
          Arrays.asList(7,8,9));
  
      List<List<Integer>> expected = Arrays.asList(
          Arrays.asList(6),
          Arrays.asList(21),
          Arrays.asList(39),
          Arrays.asList(24));
  
      JavaDStream<Integer> stream = JavaTestUtils.attachTestInputStream(ssc, inputData, 1);
      JavaDStream<Integer> reducedWindowed;
      if (withInverse) {
        reducedWindowed = stream.reduceByWindow(new IntegerSum(),
                                                new IntegerDifference(),
                                                new Duration(2000),
                                                new Duration(1000));
      } else {
        reducedWindowed = stream.reduceByWindow(new IntegerSum(),
                                                new Duration(2000), new Duration(1000));
      }
      JavaTestUtils.attachTestOutputStream(reducedWindowed);
      List<List<Integer>> result = JavaTestUtils.runStreams(ssc, 4, 4);
  
      Assert.assertEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testQueueStream() {
      ssc.stop();
      // Create a new JavaStreamingContext without checkpointing
      SparkConf conf = new SparkConf()
          .setMaster("local[2]")
          .setAppName("test")
          .set("spark.streaming.clock", "org.apache.spark.util.ManualClock");
      ssc = new JavaStreamingContext(conf, new Duration(1000));
  
      List<List<Integer>> expected = Arrays.asList(
          Arrays.asList(1,2,3),
          Arrays.asList(4,5,6),
          Arrays.asList(7,8,9));
  
      JavaSparkContext jsc = new JavaSparkContext(ssc.ssc().sc());
      JavaRDD<Integer> rdd1 = jsc.parallelize(Arrays.asList(1, 2, 3));
      JavaRDD<Integer> rdd2 = jsc.parallelize(Arrays.asList(4, 5, 6));
      JavaRDD<Integer> rdd3 = jsc.parallelize(Arrays.asList(7,8,9));
  
      Queue<JavaRDD<Integer>> rdds = new LinkedList<>();
      rdds.add(rdd1);
      rdds.add(rdd2);
      rdds.add(rdd3);
  
      JavaDStream<Integer> stream = ssc.queueStream(rdds);
      JavaTestUtils.attachTestOutputStream(stream);
      List<List<Integer>> result = JavaTestUtils.runStreams(ssc, 3, 3);
      Assert.assertEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testTransform() {
      List<List<Integer>> inputData = Arrays.asList(
          Arrays.asList(1,2,3),
          Arrays.asList(4,5,6),
          Arrays.asList(7,8,9));
  
      List<List<Integer>> expected = Arrays.asList(
          Arrays.asList(3,4,5),
          Arrays.asList(6,7,8),
          Arrays.asList(9,10,11));
  
      JavaDStream<Integer> stream = JavaTestUtils.attachTestInputStream(ssc, inputData, 1);
      JavaDStream<Integer> transformed = stream.transform(
        new Function<JavaRDD<Integer>, JavaRDD<Integer>>() {
          @Override
          public JavaRDD<Integer> call(JavaRDD<Integer> in) {
            return in.map(new Function<Integer, Integer>() {
              @Override
              public Integer call(Integer i) {
                return i + 2;
              }
            });
          }
        });
  
      JavaTestUtils.attachTestOutputStream(transformed);
      List<List<Integer>> result = JavaTestUtils.runStreams(ssc, 3, 3);
  
      assertOrderInvariantEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testVariousTransform() {
      // tests whether all variations of transform can be called from Java
  
      List<List<Integer>> inputData = Arrays.asList(Arrays.asList(1));
      JavaDStream<Integer> stream = JavaTestUtils.attachTestInputStream(ssc, inputData, 1);
  
      List<List<Tuple2<String, Integer>>> pairInputData =
          Arrays.asList(Arrays.asList(new Tuple2<>("x", 1)));
      JavaPairDStream<String, Integer> pairStream = JavaPairDStream.fromJavaDStream(
          JavaTestUtils.attachTestInputStream(ssc, pairInputData, 1));
  
      stream.transform(
          new Function<JavaRDD<Integer>, JavaRDD<Integer>>() {
            @Override
            public JavaRDD<Integer> call(JavaRDD<Integer> in) {
              return null;
            }
          }
      );
  
      stream.transform(
        new Function2<JavaRDD<Integer>, Time, JavaRDD<Integer>>() {
          @Override public JavaRDD<Integer> call(JavaRDD<Integer> in, Time time) {
            return null;
          }
        }
      );
  
      stream.transformToPair(
          new Function<JavaRDD<Integer>, JavaPairRDD<String, Integer>>() {
            @Override public JavaPairRDD<String, Integer> call(JavaRDD<Integer> in) {
              return null;
            }
          }
      );
  
      stream.transformToPair(
          new Function2<JavaRDD<Integer>, Time, JavaPairRDD<String, Integer>>() {
            @Override public JavaPairRDD<String, Integer> call(JavaRDD<Integer> in, Time time) {
              return null;
            }
          }
      );
  
      pairStream.transform(
          new Function<JavaPairRDD<String, Integer>, JavaRDD<Integer>>() {
            @Override public JavaRDD<Integer> call(JavaPairRDD<String, Integer> in) {
              return null;
            }
          }
      );
  
      pairStream.transform(
          new Function2<JavaPairRDD<String, Integer>, Time, JavaRDD<Integer>>() {
            @Override public JavaRDD<Integer> call(JavaPairRDD<String, Integer> in, Time time) {
              return null;
            }
          }
      );
  
      pairStream.transformToPair(
          new Function<JavaPairRDD<String, Integer>, JavaPairRDD<String, String>>() {
            @Override public JavaPairRDD<String, String> call(JavaPairRDD<String, Integer> in) {
              return null;
            }
          }
      );
  
      pairStream.transformToPair(
          new Function2<JavaPairRDD<String, Integer>, Time, JavaPairRDD<String, String>>() {
            @Override public JavaPairRDD<String, String> call(JavaPairRDD<String, Integer> in,
                                                              Time time) {
              return null;
            }
          }
      );
  
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testTransformWith() {
      List<List<Tuple2<String, String>>> stringStringKVStream1 = Arrays.asList(
          Arrays.asList(
              new Tuple2<>("california", "dodgers"),
              new Tuple2<>("new york", "yankees")),
          Arrays.asList(
              new Tuple2<>("california", "sharks"),
              new Tuple2<>("new york", "rangers")));
  
      List<List<Tuple2<String, String>>> stringStringKVStream2 = Arrays.asList(
          Arrays.asList(
              new Tuple2<>("california", "giants"),
              new Tuple2<>("new york", "mets")),
          Arrays.asList(
              new Tuple2<>("california", "ducks"),
              new Tuple2<>("new york", "islanders")));
  
  
      List<HashSet<Tuple2<String, Tuple2<String, String>>>> expected = Arrays.asList(
          Sets.newHashSet(
              new Tuple2<>("california",
                           new Tuple2<>("dodgers", "giants")),
              new Tuple2<>("new york",
                           new Tuple2<>("yankees", "mets"))),
          Sets.newHashSet(
              new Tuple2<>("california",
                           new Tuple2<>("sharks", "ducks")),
              new Tuple2<>("new york",
                           new Tuple2<>("rangers", "islanders"))));
  
      JavaDStream<Tuple2<String, String>> stream1 = JavaTestUtils.attachTestInputStream(
          ssc, stringStringKVStream1, 1);
      JavaPairDStream<String, String> pairStream1 = JavaPairDStream.fromJavaDStream(stream1);
  
      JavaDStream<Tuple2<String, String>> stream2 = JavaTestUtils.attachTestInputStream(
          ssc, stringStringKVStream2, 1);
      JavaPairDStream<String, String> pairStream2 = JavaPairDStream.fromJavaDStream(stream2);
  
      JavaPairDStream<String, Tuple2<String, String>> joined = pairStream1.transformWithToPair(
          pairStream2,
          new Function3<
              JavaPairRDD<String, String>,
              JavaPairRDD<String, String>,
              Time,
              JavaPairRDD<String, Tuple2<String, String>>>() {
            @Override
            public JavaPairRDD<String, Tuple2<String, String>> call(
                JavaPairRDD<String, String> rdd1,
                JavaPairRDD<String, String> rdd2,
                Time time) {
              return rdd1.join(rdd2);
            }
          }
      );
  
      JavaTestUtils.attachTestOutputStream(joined);
      List<List<Tuple2<String, Tuple2<String, String>>>> result = JavaTestUtils.runStreams(ssc, 2, 2);
      List<HashSet<Tuple2<String, Tuple2<String, String>>>> unorderedResult = new ArrayList<>();
      for (List<Tuple2<String, Tuple2<String, String>>> res: result) {
        unorderedResult.add(Sets.newHashSet(res));
      }
  
      Assert.assertEquals(expected, unorderedResult);
    }
  
  
    @SuppressWarnings("unchecked")
    @Test
    public void testVariousTransformWith() {
      // tests whether all variations of transformWith can be called from Java
  
      List<List<Integer>> inputData1 = Arrays.asList(Arrays.asList(1));
      List<List<String>> inputData2 = Arrays.asList(Arrays.asList("x"));
      JavaDStream<Integer> stream1 = JavaTestUtils.attachTestInputStream(ssc, inputData1, 1);
      JavaDStream<String> stream2 = JavaTestUtils.attachTestInputStream(ssc, inputData2, 1);
  
      List<List<Tuple2<String, Integer>>> pairInputData1 =
          Arrays.asList(Arrays.asList(new Tuple2<>("x", 1)));
      List<List<Tuple2<Double, Character>>> pairInputData2 =
          Arrays.asList(Arrays.asList(new Tuple2<>(1.0, 'x')));
      JavaPairDStream<String, Integer> pairStream1 = JavaPairDStream.fromJavaDStream(
          JavaTestUtils.attachTestInputStream(ssc, pairInputData1, 1));
      JavaPairDStream<Double, Character> pairStream2 = JavaPairDStream.fromJavaDStream(
          JavaTestUtils.attachTestInputStream(ssc, pairInputData2, 1));
  
      stream1.transformWith(
          stream2,
          new Function3<JavaRDD<Integer>, JavaRDD<String>, Time, JavaRDD<Double>>() {
            @Override
            public JavaRDD<Double> call(JavaRDD<Integer> rdd1, JavaRDD<String> rdd2, Time time) {
              return null;
            }
          }
      );
  
      stream1.transformWith(
          pairStream1,
          new Function3<JavaRDD<Integer>, JavaPairRDD<String, Integer>, Time, JavaRDD<Double>>() {
            @Override
            public JavaRDD<Double> call(JavaRDD<Integer> rdd1, JavaPairRDD<String, Integer> rdd2,
                                        Time time) {
              return null;
            }
          }
      );
  
      stream1.transformWithToPair(
          stream2,
          new Function3<JavaRDD<Integer>, JavaRDD<String>, Time, JavaPairRDD<Double, Double>>() {
            @Override
            public JavaPairRDD<Double, Double> call(JavaRDD<Integer> rdd1, JavaRDD<String> rdd2,
                                                    Time time) {
              return null;
            }
          }
      );
  
      stream1.transformWithToPair(
          pairStream1,
          new Function3<JavaRDD<Integer>, JavaPairRDD<String, Integer>, Time,
            JavaPairRDD<Double, Double>>() {
            @Override
            public JavaPairRDD<Double, Double> call(JavaRDD<Integer> rdd1,
                                                    JavaPairRDD<String, Integer> rdd2,
                                                    Time time) {
              return null;
            }
          }
      );
  
      pairStream1.transformWith(
          stream2,
          new Function3<JavaPairRDD<String, Integer>, JavaRDD<String>, Time, JavaRDD<Double>>() {
            @Override
            public JavaRDD<Double> call(JavaPairRDD<String, Integer> rdd1, JavaRDD<String> rdd2,
                                        Time time) {
              return null;
            }
          }
      );
  
      pairStream1.transformWith(
          pairStream1,
          new Function3<JavaPairRDD<String, Integer>, JavaPairRDD<String, Integer>, Time,
            JavaRDD<Double>>() {
            @Override
            public JavaRDD<Double> call(JavaPairRDD<String, Integer> rdd1,
                                        JavaPairRDD<String, Integer> rdd2,
                                        Time time) {
              return null;
            }
          }
      );
  
      pairStream1.transformWithToPair(
          stream2,
          new Function3<JavaPairRDD<String, Integer>, JavaRDD<String>, Time,
            JavaPairRDD<Double, Double>>() {
            @Override
            public JavaPairRDD<Double, Double> call(JavaPairRDD<String, Integer> rdd1,
                                                    JavaRDD<String> rdd2,
                                                    Time time) {
              return null;
            }
          }
      );
  
      pairStream1.transformWithToPair(
          pairStream2,
          new Function3<JavaPairRDD<String, Integer>, JavaPairRDD<Double, Character>, Time,
            JavaPairRDD<Double, Double>>() {
            @Override
            public JavaPairRDD<Double, Double> call(JavaPairRDD<String, Integer> rdd1,
                                                    JavaPairRDD<Double, Character> rdd2,
                                                    Time time) {
              return null;
            }
          }
      );
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testStreamingContextTransform(){
      List<List<Integer>> stream1input = Arrays.asList(
          Arrays.asList(1),
          Arrays.asList(2)
      );
  
      List<List<Integer>> stream2input = Arrays.asList(
          Arrays.asList(3),
          Arrays.asList(4)
      );
  
      List<List<Tuple2<Integer, String>>> pairStream1input = Arrays.asList(
          Arrays.asList(new Tuple2<>(1, "x")),
          Arrays.asList(new Tuple2<>(2, "y"))
      );
  
      List<List<Tuple2<Integer, Tuple2<Integer, String>>>> expected = Arrays.asList(
          Arrays.asList(new Tuple2<>(1, new Tuple2<>(1, "x"))),
          Arrays.asList(new Tuple2<>(2, new Tuple2<>(2, "y")))
      );
  
      JavaDStream<Integer> stream1 = JavaTestUtils.attachTestInputStream(ssc, stream1input, 1);
      JavaDStream<Integer> stream2 = JavaTestUtils.attachTestInputStream(ssc, stream2input, 1);
      JavaPairDStream<Integer, String> pairStream1 = JavaPairDStream.fromJavaDStream(
          JavaTestUtils.attachTestInputStream(ssc, pairStream1input, 1));
  
      List<JavaDStream<?>> listOfDStreams1 = Arrays.<JavaDStream<?>>asList(stream1, stream2);
  
      // This is just to test whether this transform to JavaStream compiles
      ssc.transform(
        listOfDStreams1,
        new Function2<List<JavaRDD<?>>, Time, JavaRDD<Long>>() {
          @Override
          public JavaRDD<Long> call(List<JavaRDD<?>> listOfRDDs, Time time) {
            Assert.assertEquals(2, listOfRDDs.size());
            return null;
          }
        }
      );
  
      List<JavaDStream<?>> listOfDStreams2 =
          Arrays.<JavaDStream<?>>asList(stream1, stream2, pairStream1.toJavaDStream());
  
      JavaPairDStream<Integer, Tuple2<Integer, String>> transformed2 = ssc.transformToPair(
        listOfDStreams2,
        new Function2<List<JavaRDD<?>>, Time, JavaPairRDD<Integer, Tuple2<Integer, String>>>() {
          @Override
          public JavaPairRDD<Integer, Tuple2<Integer, String>> call(List<JavaRDD<?>> listOfRDDs,
                                                                    Time time) {
            Assert.assertEquals(3, listOfRDDs.size());
            JavaRDD<Integer> rdd1 = (JavaRDD<Integer>)listOfRDDs.get(0);
            JavaRDD<Integer> rdd2 = (JavaRDD<Integer>)listOfRDDs.get(1);
            JavaRDD<Tuple2<Integer, String>> rdd3 =
              (JavaRDD<Tuple2<Integer, String>>)listOfRDDs.get(2);
            JavaPairRDD<Integer, String> prdd3 = JavaPairRDD.fromJavaRDD(rdd3);
            PairFunction<Integer, Integer, Integer> mapToTuple =
              new PairFunction<Integer, Integer, Integer>() {
              @Override
              public Tuple2<Integer, Integer> call(Integer i) {
                return new Tuple2<>(i, i);
              }
            };
            return rdd1.union(rdd2).mapToPair(mapToTuple).join(prdd3);
          }
        }
      );
      JavaTestUtils.attachTestOutputStream(transformed2);
      List<List<Tuple2<Integer, Tuple2<Integer, String>>>> result =
        JavaTestUtils.runStreams(ssc, 2, 2);
      Assert.assertEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testFlatMap() {
      List<List<String>> inputData = Arrays.asList(
          Arrays.asList("go", "giants"),
          Arrays.asList("boo", "dodgers"),
          Arrays.asList("athletics"));
  
      List<List<String>> expected = Arrays.asList(
          Arrays.asList("g","o","g","i","a","n","t","s"),
          Arrays.asList("b", "o", "o", "d","o","d","g","e","r","s"),
          Arrays.asList("a","t","h","l","e","t","i","c","s"));
  
      JavaDStream<String> stream = JavaTestUtils.attachTestInputStream(ssc, inputData, 1);
      JavaDStream<String> flatMapped = stream.flatMap(new FlatMapFunction<String, String>() {
        @Override
        public Iterator<String> call(String x) {
          return Arrays.asList(x.split("(?!^)")).iterator();
        }
      });
      JavaTestUtils.attachTestOutputStream(flatMapped);
      List<List<String>> result = JavaTestUtils.runStreams(ssc, 3, 3);
  
      assertOrderInvariantEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testForeachRDD() {
      final LongAccumulator accumRdd = ssc.sparkContext().sc().longAccumulator();
      final LongAccumulator accumEle = ssc.sparkContext().sc().longAccumulator();
      List<List<Integer>> inputData = Arrays.asList(
          Arrays.asList(1,1,1),
          Arrays.asList(1,1,1));
  
      JavaDStream<Integer> stream = JavaTestUtils.attachTestInputStream(ssc, inputData, 1);
      JavaTestUtils.attachTestOutputStream(stream.count()); // dummy output
  
      stream.foreachRDD(new VoidFunction<JavaRDD<Integer>>() {
        @Override
        public void call(JavaRDD<Integer> rdd) {
          accumRdd.add(1);
          rdd.foreach(new VoidFunction<Integer>() {
            @Override
            public void call(Integer i) {
              accumEle.add(1);
            }
          });
        }
      });
  
      // This is a test to make sure foreachRDD(VoidFunction2) can be called from Java
      stream.foreachRDD(new VoidFunction2<JavaRDD<Integer>, Time>() {
        @Override
        public void call(JavaRDD<Integer> rdd, Time time) {
        }
      });
  
      JavaTestUtils.runStreams(ssc, 2, 2);
  
      Assert.assertEquals(2, accumRdd.value().intValue());
      Assert.assertEquals(6, accumEle.value().intValue());
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testPairFlatMap() {
      List<List<String>> inputData = Arrays.asList(
          Arrays.asList("giants"),
          Arrays.asList("dodgers"),
          Arrays.asList("athletics"));
  
      List<List<Tuple2<Integer, String>>> expected = Arrays.asList(
          Arrays.asList(
              new Tuple2<>(6, "g"),
              new Tuple2<>(6, "i"),
              new Tuple2<>(6, "a"),
              new Tuple2<>(6, "n"),
              new Tuple2<>(6, "t"),
              new Tuple2<>(6, "s")),
          Arrays.asList(
              new Tuple2<>(7, "d"),
              new Tuple2<>(7, "o"),
              new Tuple2<>(7, "d"),
              new Tuple2<>(7, "g"),
              new Tuple2<>(7, "e"),
              new Tuple2<>(7, "r"),
              new Tuple2<>(7, "s")),
          Arrays.asList(
              new Tuple2<>(9, "a"),
              new Tuple2<>(9, "t"),
              new Tuple2<>(9, "h"),
              new Tuple2<>(9, "l"),
              new Tuple2<>(9, "e"),
              new Tuple2<>(9, "t"),
              new Tuple2<>(9, "i"),
              new Tuple2<>(9, "c"),
              new Tuple2<>(9, "s")));
  
      JavaDStream<String> stream = JavaTestUtils.attachTestInputStream(ssc, inputData, 1);
      JavaPairDStream<Integer, String> flatMapped = stream.flatMapToPair(
        new PairFlatMapFunction<String, Integer, String>() {
          @Override
          public Iterator<Tuple2<Integer, String>> call(String in) {
            List<Tuple2<Integer, String>> out = new ArrayList<>();
            for (String letter: in.split("(?!^)")) {
              out.add(new Tuple2<>(in.length(), letter));
            }
            return out.iterator();
          }
        });
      JavaTestUtils.attachTestOutputStream(flatMapped);
      List<List<Tuple2<Integer, String>>> result = JavaTestUtils.runStreams(ssc, 3, 3);
  
      Assert.assertEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testUnion() {
      List<List<Integer>> inputData1 = Arrays.asList(
          Arrays.asList(1,1),
          Arrays.asList(2,2),
          Arrays.asList(3,3));
  
      List<List<Integer>> inputData2 = Arrays.asList(
          Arrays.asList(4,4),
          Arrays.asList(5,5),
          Arrays.asList(6,6));
  
      List<List<Integer>> expected = Arrays.asList(
          Arrays.asList(1,1,4,4),
          Arrays.asList(2,2,5,5),
          Arrays.asList(3,3,6,6));
  
      JavaDStream<Integer> stream1 = JavaTestUtils.attachTestInputStream(ssc, inputData1, 2);
      JavaDStream<Integer> stream2 = JavaTestUtils.attachTestInputStream(ssc, inputData2, 2);
  
      JavaDStream<Integer> unioned = stream1.union(stream2);
      JavaTestUtils.attachTestOutputStream(unioned);
      List<List<Integer>> result = JavaTestUtils.runStreams(ssc, 3, 3);
  
      assertOrderInvariantEquals(expected, result);
    }
  
    /*
     * Performs an order-invariant comparison of lists representing two RDD streams. This allows
     * us to account for ordering variation within individual RDD's which occurs during windowing.
     */
    public static <T> void assertOrderInvariantEquals(
        List<List<T>> expected, List<List<T>> actual) {
      List<Set<T>> expectedSets = new ArrayList<>();
      for (List<T> list: expected) {
        expectedSets.add(Collections.unmodifiableSet(new HashSet<>(list)));
      }
      List<Set<T>> actualSets = new ArrayList<>();
      for (List<T> list: actual) {
        actualSets.add(Collections.unmodifiableSet(new HashSet<>(list)));
      }
      Assert.assertEquals(expectedSets, actualSets);
    }
  
  
    // PairDStream Functions
    @SuppressWarnings("unchecked")
    @Test
    public void testPairFilter() {
      List<List<String>> inputData = Arrays.asList(
          Arrays.asList("giants", "dodgers"),
          Arrays.asList("yankees", "red sox"));
  
      List<List<Tuple2<String, Integer>>> expected = Arrays.asList(
          Arrays.asList(new Tuple2<>("giants", 6)),
          Arrays.asList(new Tuple2<>("yankees", 7)));
  
      JavaDStream<String> stream = JavaTestUtils.attachTestInputStream(ssc, inputData, 1);
      JavaPairDStream<String, Integer> pairStream = stream.mapToPair(
          new PairFunction<String, String, Integer>() {
            @Override
            public Tuple2<String, Integer> call(String in) {
              return new Tuple2<>(in, in.length());
            }
          });
  
      JavaPairDStream<String, Integer> filtered = pairStream.filter(
          new Function<Tuple2<String, Integer>, Boolean>() {
        @Override
        public Boolean call(Tuple2<String, Integer> in) {
          return in._1().contains("a");
        }
      });
      JavaTestUtils.attachTestOutputStream(filtered);
      List<List<Tuple2<String, Integer>>> result = JavaTestUtils.runStreams(ssc, 2, 2);
  
      Assert.assertEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    private final List<List<Tuple2<String, String>>> stringStringKVStream = Arrays.asList(
        Arrays.asList(new Tuple2<>("california", "dodgers"),
                      new Tuple2<>("california", "giants"),
                      new Tuple2<>("new york", "yankees"),
                      new Tuple2<>("new york", "mets")),
        Arrays.asList(new Tuple2<>("california", "sharks"),
                      new Tuple2<>("california", "ducks"),
                      new Tuple2<>("new york", "rangers"),
                      new Tuple2<>("new york", "islanders")));
  
    @SuppressWarnings("unchecked")
    private final List<List<Tuple2<String, Integer>>> stringIntKVStream = Arrays.asList(
        Arrays.asList(
            new Tuple2<>("california", 1),
            new Tuple2<>("california", 3),
            new Tuple2<>("new york", 4),
            new Tuple2<>("new york", 1)),
        Arrays.asList(
            new Tuple2<>("california", 5),
            new Tuple2<>("california", 5),
            new Tuple2<>("new york", 3),
            new Tuple2<>("new york", 1)));
  
    @SuppressWarnings("unchecked")
    @Test
    public void testPairMap() { // Maps pair -> pair of different type
      List<List<Tuple2<String, Integer>>> inputData = stringIntKVStream;
  
      List<List<Tuple2<Integer, String>>> expected = Arrays.asList(
          Arrays.asList(
              new Tuple2<>(1, "california"),
              new Tuple2<>(3, "california"),
              new Tuple2<>(4, "new york"),
              new Tuple2<>(1, "new york")),
          Arrays.asList(
              new Tuple2<>(5, "california"),
              new Tuple2<>(5, "california"),
              new Tuple2<>(3, "new york"),
              new Tuple2<>(1, "new york")));
  
      JavaDStream<Tuple2<String, Integer>> stream =
        JavaTestUtils.attachTestInputStream(ssc, inputData, 1);
      JavaPairDStream<String, Integer> pairStream = JavaPairDStream.fromJavaDStream(stream);
      JavaPairDStream<Integer, String> reversed = pairStream.mapToPair(
          new PairFunction<Tuple2<String, Integer>, Integer, String>() {
            @Override
            public Tuple2<Integer, String> call(Tuple2<String, Integer> in) {
              return in.swap();
            }
          });
  
      JavaTestUtils.attachTestOutputStream(reversed);
      List<List<Tuple2<Integer, String>>> result = JavaTestUtils.runStreams(ssc, 2, 2);
  
      Assert.assertEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testPairMapPartitions() { // Maps pair -> pair of different type
      List<List<Tuple2<String, Integer>>> inputData = stringIntKVStream;
  
      List<List<Tuple2<Integer, String>>> expected = Arrays.asList(
          Arrays.asList(
              new Tuple2<>(1, "california"),
              new Tuple2<>(3, "california"),
              new Tuple2<>(4, "new york"),
              new Tuple2<>(1, "new york")),
          Arrays.asList(
              new Tuple2<>(5, "california"),
              new Tuple2<>(5, "california"),
              new Tuple2<>(3, "new york"),
              new Tuple2<>(1, "new york")));
  
      JavaDStream<Tuple2<String, Integer>> stream =
        JavaTestUtils.attachTestInputStream(ssc, inputData, 1);
      JavaPairDStream<String, Integer> pairStream = JavaPairDStream.fromJavaDStream(stream);
      JavaPairDStream<Integer, String> reversed = pairStream.mapPartitionsToPair(
          new PairFlatMapFunction<Iterator<Tuple2<String, Integer>>, Integer, String>() {
            @Override
            public Iterator<Tuple2<Integer, String>> call(Iterator<Tuple2<String, Integer>> in) {
              List<Tuple2<Integer, String>> out = new LinkedList<>();
              while (in.hasNext()) {
                Tuple2<String, Integer> next = in.next();
                out.add(next.swap());
              }
              return out.iterator();
            }
          });
  
      JavaTestUtils.attachTestOutputStream(reversed);
      List<List<Tuple2<Integer, String>>> result = JavaTestUtils.runStreams(ssc, 2, 2);
  
      Assert.assertEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testPairMap2() { // Maps pair -> single
      List<List<Tuple2<String, Integer>>> inputData = stringIntKVStream;
  
      List<List<Integer>> expected = Arrays.asList(
              Arrays.asList(1, 3, 4, 1),
              Arrays.asList(5, 5, 3, 1));
  
      JavaDStream<Tuple2<String, Integer>> stream =
        JavaTestUtils.attachTestInputStream(ssc, inputData, 1);
      JavaPairDStream<String, Integer> pairStream = JavaPairDStream.fromJavaDStream(stream);
      JavaDStream<Integer> reversed = pairStream.map(
          new Function<Tuple2<String, Integer>, Integer>() {
            @Override
            public Integer call(Tuple2<String, Integer> in) {
              return in._2();
            }
          });
  
      JavaTestUtils.attachTestOutputStream(reversed);
      List<List<Integer>> result = JavaTestUtils.runStreams(ssc, 2, 2);
  
      Assert.assertEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testPairToPairFlatMapWithChangingTypes() { // Maps pair -> pair
      List<List<Tuple2<String, Integer>>> inputData = Arrays.asList(
          Arrays.asList(
              new Tuple2<>("hi", 1),
              new Tuple2<>("ho", 2)),
          Arrays.asList(
              new Tuple2<>("hi", 1),
              new Tuple2<>("ho", 2)));
  
      List<List<Tuple2<Integer, String>>> expected = Arrays.asList(
          Arrays.asList(
              new Tuple2<>(1, "h"),
              new Tuple2<>(1, "i"),
              new Tuple2<>(2, "h"),
              new Tuple2<>(2, "o")),
          Arrays.asList(
              new Tuple2<>(1, "h"),
              new Tuple2<>(1, "i"),
              new Tuple2<>(2, "h"),
              new Tuple2<>(2, "o")));
  
      JavaDStream<Tuple2<String, Integer>> stream =
          JavaTestUtils.attachTestInputStream(ssc, inputData, 1);
      JavaPairDStream<String, Integer> pairStream = JavaPairDStream.fromJavaDStream(stream);
      JavaPairDStream<Integer, String> flatMapped = pairStream.flatMapToPair(
          new PairFlatMapFunction<Tuple2<String, Integer>, Integer, String>() {
            @Override
            public Iterator<Tuple2<Integer, String>> call(Tuple2<String, Integer> in) {
              List<Tuple2<Integer, String>> out = new LinkedList<>();
              for (Character s : in._1().toCharArray()) {
                out.add(new Tuple2<>(in._2(), s.toString()));
              }
              return out.iterator();
            }
          });
      JavaTestUtils.attachTestOutputStream(flatMapped);
      List<List<Tuple2<Integer, String>>> result = JavaTestUtils.runStreams(ssc, 2, 2);
  
      Assert.assertEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testPairGroupByKey() {
      List<List<Tuple2<String, String>>> inputData = stringStringKVStream;
  
      List<List<Tuple2<String, List<String>>>> expected = Arrays.asList(
          Arrays.asList(
              new Tuple2<>("california", Arrays.asList("dodgers", "giants")),
              new Tuple2<>("new york", Arrays.asList("yankees", "mets"))),
          Arrays.asList(
              new Tuple2<>("california", Arrays.asList("sharks", "ducks")),
              new Tuple2<>("new york", Arrays.asList("rangers", "islanders"))));
  
      JavaDStream<Tuple2<String, String>> stream =
        JavaTestUtils.attachTestInputStream(ssc, inputData, 1);
      JavaPairDStream<String, String> pairStream = JavaPairDStream.fromJavaDStream(stream);
  
      JavaPairDStream<String, Iterable<String>> grouped = pairStream.groupByKey();
      JavaTestUtils.attachTestOutputStream(grouped);
      List<List<Tuple2<String, Iterable<String>>>> result = JavaTestUtils.runStreams(ssc, 2, 2);
  
      Assert.assertEquals(expected.size(), result.size());
      Iterator<List<Tuple2<String, Iterable<String>>>> resultItr = result.iterator();
      Iterator<List<Tuple2<String, List<String>>>> expectedItr = expected.iterator();
      while (resultItr.hasNext() && expectedItr.hasNext()) {
        Iterator<Tuple2<String, Iterable<String>>> resultElements = resultItr.next().iterator();
        Iterator<Tuple2<String, List<String>>> expectedElements = expectedItr.next().iterator();
        while (resultElements.hasNext() && expectedElements.hasNext()) {
          Tuple2<String, Iterable<String>> resultElement = resultElements.next();
          Tuple2<String, List<String>> expectedElement = expectedElements.next();
          Assert.assertEquals(expectedElement._1(), resultElement._1());
          equalIterable(expectedElement._2(), resultElement._2());
        }
        Assert.assertEquals(resultElements.hasNext(), expectedElements.hasNext());
      }
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testPairReduceByKey() {
      List<List<Tuple2<String, Integer>>> inputData = stringIntKVStream;
  
      List<List<Tuple2<String, Integer>>> expected = Arrays.asList(
          Arrays.asList(
              new Tuple2<>("california", 4),
              new Tuple2<>("new york", 5)),
          Arrays.asList(
              new Tuple2<>("california", 10),
              new Tuple2<>("new york", 4)));
  
      JavaDStream<Tuple2<String, Integer>> stream = JavaTestUtils.attachTestInputStream(
          ssc, inputData, 1);
      JavaPairDStream<String, Integer> pairStream = JavaPairDStream.fromJavaDStream(stream);
  
      JavaPairDStream<String, Integer> reduced = pairStream.reduceByKey(new IntegerSum());
  
      JavaTestUtils.attachTestOutputStream(reduced);
      List<List<Tuple2<String, Integer>>> result = JavaTestUtils.runStreams(ssc, 2, 2);
  
      Assert.assertEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testCombineByKey() {
      List<List<Tuple2<String, Integer>>> inputData = stringIntKVStream;
  
      List<List<Tuple2<String, Integer>>> expected = Arrays.asList(
          Arrays.asList(
              new Tuple2<>("california", 4),
              new Tuple2<>("new york", 5)),
          Arrays.asList(
              new Tuple2<>("california", 10),
              new Tuple2<>("new york", 4)));
  
      JavaDStream<Tuple2<String, Integer>> stream = JavaTestUtils.attachTestInputStream(
          ssc, inputData, 1);
      JavaPairDStream<String, Integer> pairStream = JavaPairDStream.fromJavaDStream(stream);
  
      JavaPairDStream<String, Integer> combined = pairStream.combineByKey(
          new Function<Integer, Integer>() {
            @Override
            public Integer call(Integer i) {
              return i;
            }
          }, new IntegerSum(), new IntegerSum(), new HashPartitioner(2));
  
      JavaTestUtils.attachTestOutputStream(combined);
      List<List<Tuple2<String, Integer>>> result = JavaTestUtils.runStreams(ssc, 2, 2);
  
      Assert.assertEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testCountByValue() {
      List<List<String>> inputData = Arrays.asList(
        Arrays.asList("hello", "world"),
        Arrays.asList("hello", "moon"),
        Arrays.asList("hello"));
  
      List<List<Tuple2<String, Long>>> expected = Arrays.asList(
          Arrays.asList(
              new Tuple2<>("hello", 1L),
              new Tuple2<>("world", 1L)),
          Arrays.asList(
              new Tuple2<>("hello", 1L),
              new Tuple2<>("moon", 1L)),
          Arrays.asList(
              new Tuple2<>("hello", 1L)));
  
      JavaDStream<String> stream = JavaTestUtils.attachTestInputStream(ssc, inputData, 1);
      JavaPairDStream<String, Long> counted = stream.countByValue();
      JavaTestUtils.attachTestOutputStream(counted);
      List<List<Tuple2<String, Long>>> result = JavaTestUtils.runStreams(ssc, 3, 3);
  
      Assert.assertEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testGroupByKeyAndWindow() {
      List<List<Tuple2<String, Integer>>> inputData = stringIntKVStream;
  
      List<List<Tuple2<String, List<Integer>>>> expected = Arrays.asList(
        Arrays.asList(
          new Tuple2<>("california", Arrays.asList(1, 3)),
          new Tuple2<>("new york", Arrays.asList(1, 4))
        ),
        Arrays.asList(
          new Tuple2<>("california", Arrays.asList(1, 3, 5, 5)),
          new Tuple2<>("new york", Arrays.asList(1, 1, 3, 4))
        ),
        Arrays.asList(
          new Tuple2<>("california", Arrays.asList(5, 5)),
          new Tuple2<>("new york", Arrays.asList(1, 3))
        )
      );
  
      JavaDStream<Tuple2<String, Integer>> stream =
        JavaTestUtils.attachTestInputStream(ssc, inputData, 1);
      JavaPairDStream<String, Integer> pairStream = JavaPairDStream.fromJavaDStream(stream);
  
      JavaPairDStream<String, Iterable<Integer>> groupWindowed =
          pairStream.groupByKeyAndWindow(new Duration(2000), new Duration(1000));
      JavaTestUtils.attachTestOutputStream(groupWindowed);
      List<List<Tuple2<String, List<Integer>>>> result = JavaTestUtils.runStreams(ssc, 3, 3);
  
      Assert.assertEquals(expected.size(), result.size());
      for (int i = 0; i < result.size(); i++) {
        Assert.assertEquals(convert(expected.get(i)), convert(result.get(i)));
      }
    }
  
    private static Set<Tuple2<String, HashSet<Integer>>>
      convert(List<Tuple2<String, List<Integer>>> listOfTuples) {
      List<Tuple2<String, HashSet<Integer>>> newListOfTuples = new ArrayList<>();
      for (Tuple2<String, List<Integer>> tuple: listOfTuples) {
        newListOfTuples.add(convert(tuple));
      }
      return new HashSet<>(newListOfTuples);
    }
  
    private static Tuple2<String, HashSet<Integer>> convert(Tuple2<String, List<Integer>> tuple) {
      return new Tuple2<>(tuple._1(), new HashSet<>(tuple._2()));
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testReduceByKeyAndWindow() {
      List<List<Tuple2<String, Integer>>> inputData = stringIntKVStream;
  
      List<List<Tuple2<String, Integer>>> expected = Arrays.asList(
          Arrays.asList(new Tuple2<>("california", 4),
                        new Tuple2<>("new york", 5)),
          Arrays.asList(new Tuple2<>("california", 14),
                        new Tuple2<>("new york", 9)),
          Arrays.asList(new Tuple2<>("california", 10),
                        new Tuple2<>("new york", 4)));
  
      JavaDStream<Tuple2<String, Integer>> stream =
        JavaTestUtils.attachTestInputStream(ssc, inputData, 1);
      JavaPairDStream<String, Integer> pairStream = JavaPairDStream.fromJavaDStream(stream);
  
      JavaPairDStream<String, Integer> reduceWindowed =
          pairStream.reduceByKeyAndWindow(new IntegerSum(), new Duration(2000), new Duration(1000));
      JavaTestUtils.attachTestOutputStream(reduceWindowed);
      List<List<Tuple2<String, Integer>>> result = JavaTestUtils.runStreams(ssc, 3, 3);
  
      Assert.assertEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testUpdateStateByKey() {
      List<List<Tuple2<String, Integer>>> inputData = stringIntKVStream;
  
      List<List<Tuple2<String, Integer>>> expected = Arrays.asList(
          Arrays.asList(new Tuple2<>("california", 4),
                        new Tuple2<>("new york", 5)),
          Arrays.asList(new Tuple2<>("california", 14),
                        new Tuple2<>("new york", 9)),
          Arrays.asList(new Tuple2<>("california", 14),
                        new Tuple2<>("new york", 9)));
  
      JavaDStream<Tuple2<String, Integer>> stream =
        JavaTestUtils.attachTestInputStream(ssc, inputData, 1);
      JavaPairDStream<String, Integer> pairStream = JavaPairDStream.fromJavaDStream(stream);
  
      JavaPairDStream<String, Integer> updated = pairStream.updateStateByKey(
          new Function2<List<Integer>, Optional<Integer>, Optional<Integer>>() {
            @Override
            public Optional<Integer> call(List<Integer> values, Optional<Integer> state) {
              int out = 0;
              if (state.isPresent()) {
                out += state.get();
              }
              for (Integer v : values) {
                out += v;
              }
              return Optional.of(out);
            }
          });
      JavaTestUtils.attachTestOutputStream(updated);
      List<List<Tuple2<String, Integer>>> result = JavaTestUtils.runStreams(ssc, 3, 3);
  
      Assert.assertEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testUpdateStateByKeyWithInitial() {
      List<List<Tuple2<String, Integer>>> inputData = stringIntKVStream;
  
      List<Tuple2<String, Integer>> initial = Arrays.asList(
          new Tuple2<>("california", 1),
              new Tuple2<>("new york", 2));
  
      JavaRDD<Tuple2<String, Integer>> tmpRDD = ssc.sparkContext().parallelize(initial);
      JavaPairRDD<String, Integer> initialRDD = JavaPairRDD.fromJavaRDD(tmpRDD);
  
      List<List<Tuple2<String, Integer>>> expected = Arrays.asList(
          Arrays.asList(new Tuple2<>("california", 5),
                        new Tuple2<>("new york", 7)),
          Arrays.asList(new Tuple2<>("california", 15),
                        new Tuple2<>("new york", 11)),
          Arrays.asList(new Tuple2<>("california", 15),
                        new Tuple2<>("new york", 11)));
  
      JavaDStream<Tuple2<String, Integer>> stream =
        JavaTestUtils.attachTestInputStream(ssc, inputData, 1);
      JavaPairDStream<String, Integer> pairStream = JavaPairDStream.fromJavaDStream(stream);
  
      JavaPairDStream<String, Integer> updated = pairStream.updateStateByKey(
          new Function2<List<Integer>, Optional<Integer>, Optional<Integer>>() {
            @Override
            public Optional<Integer> call(List<Integer> values, Optional<Integer> state) {
              int out = 0;
              if (state.isPresent()) {
                out += state.get();
              }
              for (Integer v : values) {
                out += v;
              }
              return Optional.of(out);
            }
          }, new HashPartitioner(1), initialRDD);
      JavaTestUtils.attachTestOutputStream(updated);
      List<List<Tuple2<String, Integer>>> result = JavaTestUtils.runStreams(ssc, 3, 3);
  
      assertOrderInvariantEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testReduceByKeyAndWindowWithInverse() {
      List<List<Tuple2<String, Integer>>> inputData = stringIntKVStream;
  
      List<List<Tuple2<String, Integer>>> expected = Arrays.asList(
          Arrays.asList(new Tuple2<>("california", 4),
                        new Tuple2<>("new york", 5)),
          Arrays.asList(new Tuple2<>("california", 14),
                        new Tuple2<>("new york", 9)),
          Arrays.asList(new Tuple2<>("california", 10),
                        new Tuple2<>("new york", 4)));
  
      JavaDStream<Tuple2<String, Integer>> stream =
        JavaTestUtils.attachTestInputStream(ssc, inputData, 1);
      JavaPairDStream<String, Integer> pairStream = JavaPairDStream.fromJavaDStream(stream);
  
      JavaPairDStream<String, Integer> reduceWindowed =
          pairStream.reduceByKeyAndWindow(new IntegerSum(), new IntegerDifference(),
                                          new Duration(2000), new Duration(1000));
      JavaTestUtils.attachTestOutputStream(reduceWindowed);
      List<List<Tuple2<String, Integer>>> result = JavaTestUtils.runStreams(ssc, 3, 3);
  
      Assert.assertEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testCountByValueAndWindow() {
      List<List<String>> inputData = Arrays.asList(
          Arrays.asList("hello", "world"),
          Arrays.asList("hello", "moon"),
          Arrays.asList("hello"));
  
      List<HashSet<Tuple2<String, Long>>> expected = Arrays.asList(
          Sets.newHashSet(
              new Tuple2<>("hello", 1L),
              new Tuple2<>("world", 1L)),
          Sets.newHashSet(
              new Tuple2<>("hello", 2L),
              new Tuple2<>("world", 1L),
              new Tuple2<>("moon", 1L)),
          Sets.newHashSet(
              new Tuple2<>("hello", 2L),
              new Tuple2<>("moon", 1L)));
  
      JavaDStream<String> stream = JavaTestUtils.attachTestInputStream(
          ssc, inputData, 1);
      JavaPairDStream<String, Long> counted =
        stream.countByValueAndWindow(new Duration(2000), new Duration(1000));
      JavaTestUtils.attachTestOutputStream(counted);
      List<List<Tuple2<String, Long>>> result = JavaTestUtils.runStreams(ssc, 3, 3);
      List<Set<Tuple2<String, Long>>> unorderedResult = new ArrayList<>();
      for (List<Tuple2<String, Long>> res: result) {
        unorderedResult.add(Sets.newHashSet(res));
      }
  
      Assert.assertEquals(expected, unorderedResult);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testPairTransform() {
      List<List<Tuple2<Integer, Integer>>> inputData = Arrays.asList(
          Arrays.asList(
              new Tuple2<>(3, 5),
              new Tuple2<>(1, 5),
              new Tuple2<>(4, 5),
              new Tuple2<>(2, 5)),
          Arrays.asList(
              new Tuple2<>(2, 5),
              new Tuple2<>(3, 5),
              new Tuple2<>(4, 5),
              new Tuple2<>(1, 5)));
  
      List<List<Tuple2<Integer, Integer>>> expected = Arrays.asList(
          Arrays.asList(
              new Tuple2<>(1, 5),
              new Tuple2<>(2, 5),
              new Tuple2<>(3, 5),
              new Tuple2<>(4, 5)),
          Arrays.asList(
              new Tuple2<>(1, 5),
              new Tuple2<>(2, 5),
              new Tuple2<>(3, 5),
              new Tuple2<>(4, 5)));
  
      JavaDStream<Tuple2<Integer, Integer>> stream = JavaTestUtils.attachTestInputStream(
          ssc, inputData, 1);
      JavaPairDStream<Integer, Integer> pairStream = JavaPairDStream.fromJavaDStream(stream);
  
      JavaPairDStream<Integer, Integer> sorted = pairStream.transformToPair(
          new Function<JavaPairRDD<Integer, Integer>, JavaPairRDD<Integer, Integer>>() {
            @Override
            public JavaPairRDD<Integer, Integer> call(JavaPairRDD<Integer, Integer> in) {
              return in.sortByKey();
            }
          });
  
      JavaTestUtils.attachTestOutputStream(sorted);
      List<List<Tuple2<Integer, Integer>>> result = JavaTestUtils.runStreams(ssc, 2, 2);
  
      Assert.assertEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testPairToNormalRDDTransform() {
      List<List<Tuple2<Integer, Integer>>> inputData = Arrays.asList(
          Arrays.asList(
              new Tuple2<>(3, 5),
              new Tuple2<>(1, 5),
              new Tuple2<>(4, 5),
              new Tuple2<>(2, 5)),
          Arrays.asList(
              new Tuple2<>(2, 5),
              new Tuple2<>(3, 5),
              new Tuple2<>(4, 5),
              new Tuple2<>(1, 5)));
  
      List<List<Integer>> expected = Arrays.asList(
          Arrays.asList(3,1,4,2),
          Arrays.asList(2,3,4,1));
  
      JavaDStream<Tuple2<Integer, Integer>> stream = JavaTestUtils.attachTestInputStream(
          ssc, inputData, 1);
      JavaPairDStream<Integer, Integer> pairStream = JavaPairDStream.fromJavaDStream(stream);
  
      JavaDStream<Integer> firstParts = pairStream.transform(
          new Function<JavaPairRDD<Integer, Integer>, JavaRDD<Integer>>() {
            @Override
            public JavaRDD<Integer> call(JavaPairRDD<Integer, Integer> in) {
              return in.map(new Function<Tuple2<Integer, Integer>, Integer>() {
                @Override
                public Integer call(Tuple2<Integer, Integer> in2) {
                  return in2._1();
                }
              });
            }
          });
  
      JavaTestUtils.attachTestOutputStream(firstParts);
      List<List<Integer>> result = JavaTestUtils.runStreams(ssc, 2, 2);
  
      Assert.assertEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testMapValues() {
      List<List<Tuple2<String, String>>> inputData = stringStringKVStream;
  
      List<List<Tuple2<String, String>>> expected = Arrays.asList(
          Arrays.asList(new Tuple2<>("california", "DODGERS"),
                        new Tuple2<>("california", "GIANTS"),
                        new Tuple2<>("new york", "YANKEES"),
                        new Tuple2<>("new york", "METS")),
          Arrays.asList(new Tuple2<>("california", "SHARKS"),
                        new Tuple2<>("california", "DUCKS"),
                        new Tuple2<>("new york", "RANGERS"),
                        new Tuple2<>("new york", "ISLANDERS")));
  
      JavaDStream<Tuple2<String, String>> stream = JavaTestUtils.attachTestInputStream(
          ssc, inputData, 1);
      JavaPairDStream<String, String> pairStream = JavaPairDStream.fromJavaDStream(stream);
  
      JavaPairDStream<String, String> mapped = pairStream.mapValues(new Function<String, String>() {
        @Override
        public String call(String s) {
          return s.toUpperCase(Locale.ENGLISH);
        }
      });
  
      JavaTestUtils.attachTestOutputStream(mapped);
      List<List<Tuple2<String, String>>> result = JavaTestUtils.runStreams(ssc, 2, 2);
  
      Assert.assertEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testFlatMapValues() {
      List<List<Tuple2<String, String>>> inputData = stringStringKVStream;
  
      List<List<Tuple2<String, String>>> expected = Arrays.asList(
          Arrays.asList(new Tuple2<>("california", "dodgers1"),
                        new Tuple2<>("california", "dodgers2"),
                        new Tuple2<>("california", "giants1"),
                        new Tuple2<>("california", "giants2"),
                        new Tuple2<>("new york", "yankees1"),
                        new Tuple2<>("new york", "yankees2"),
                        new Tuple2<>("new york", "mets1"),
                        new Tuple2<>("new york", "mets2")),
          Arrays.asList(new Tuple2<>("california", "sharks1"),
                        new Tuple2<>("california", "sharks2"),
                        new Tuple2<>("california", "ducks1"),
                        new Tuple2<>("california", "ducks2"),
                        new Tuple2<>("new york", "rangers1"),
                        new Tuple2<>("new york", "rangers2"),
                        new Tuple2<>("new york", "islanders1"),
                        new Tuple2<>("new york", "islanders2")));
  
      JavaDStream<Tuple2<String, String>> stream = JavaTestUtils.attachTestInputStream(
          ssc, inputData, 1);
      JavaPairDStream<String, String> pairStream = JavaPairDStream.fromJavaDStream(stream);
  
  
      JavaPairDStream<String, String> flatMapped = pairStream.flatMapValues(
          new Function<String, Iterable<String>>() {
            @Override
            public Iterable<String> call(String in) {
              List<String> out = new ArrayList<>();
              out.add(in + "1");
              out.add(in + "2");
              return out;
            }
          });
  
      JavaTestUtils.attachTestOutputStream(flatMapped);
      List<List<Tuple2<String, String>>> result = JavaTestUtils.runStreams(ssc, 2, 2);
  
      Assert.assertEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testCoGroup() {
      List<List<Tuple2<String, String>>> stringStringKVStream1 = Arrays.asList(
          Arrays.asList(new Tuple2<>("california", "dodgers"),
                        new Tuple2<>("new york", "yankees")),
          Arrays.asList(new Tuple2<>("california", "sharks"),
                        new Tuple2<>("new york", "rangers")));
  
      List<List<Tuple2<String, String>>> stringStringKVStream2 = Arrays.asList(
          Arrays.asList(new Tuple2<>("california", "giants"),
                        new Tuple2<>("new york", "mets")),
          Arrays.asList(new Tuple2<>("california", "ducks"),
                        new Tuple2<>("new york", "islanders")));
  
  
      List<List<Tuple2<String, Tuple2<List<String>, List<String>>>>> expected = Arrays.asList(
          Arrays.asList(
              new Tuple2<>("california",
                           new Tuple2<>(Arrays.asList("dodgers"), Arrays.asList("giants"))),
              new Tuple2<>("new york",
                           new Tuple2<>(Arrays.asList("yankees"), Arrays.asList("mets")))),
          Arrays.asList(
              new Tuple2<>("california",
                           new Tuple2<>(Arrays.asList("sharks"), Arrays.asList("ducks"))),
              new Tuple2<>("new york",
                           new Tuple2<>(Arrays.asList("rangers"), Arrays.asList("islanders")))));
  
  
      JavaDStream<Tuple2<String, String>> stream1 = JavaTestUtils.attachTestInputStream(
          ssc, stringStringKVStream1, 1);
      JavaPairDStream<String, String> pairStream1 = JavaPairDStream.fromJavaDStream(stream1);
  
      JavaDStream<Tuple2<String, String>> stream2 = JavaTestUtils.attachTestInputStream(
          ssc, stringStringKVStream2, 1);
      JavaPairDStream<String, String> pairStream2 = JavaPairDStream.fromJavaDStream(stream2);
  
      JavaPairDStream<String, Tuple2<Iterable<String>, Iterable<String>>> grouped =
          pairStream1.cogroup(pairStream2);
      JavaTestUtils.attachTestOutputStream(grouped);
      List<List<Tuple2<String, Tuple2<Iterable<String>, Iterable<String>>>>> result =
          JavaTestUtils.runStreams(ssc, 2, 2);
  
      Assert.assertEquals(expected.size(), result.size());
      Iterator<List<Tuple2<String, Tuple2<Iterable<String>, Iterable<String>>>>> resultItr =
          result.iterator();
      Iterator<List<Tuple2<String, Tuple2<List<String>, List<String>>>>> expectedItr =
          expected.iterator();
      while (resultItr.hasNext() && expectedItr.hasNext()) {
        Iterator<Tuple2<String, Tuple2<Iterable<String>, Iterable<String>>>> resultElements =
            resultItr.next().iterator();
        Iterator<Tuple2<String, Tuple2<List<String>, List<String>>>> expectedElements =
            expectedItr.next().iterator();
        while (resultElements.hasNext() && expectedElements.hasNext()) {
          Tuple2<String, Tuple2<Iterable<String>, Iterable<String>>> resultElement =
              resultElements.next();
          Tuple2<String, Tuple2<List<String>, List<String>>> expectedElement =
              expectedElements.next();
          Assert.assertEquals(expectedElement._1(), resultElement._1());
          equalIterable(expectedElement._2()._1(), resultElement._2()._1());
          equalIterable(expectedElement._2()._2(), resultElement._2()._2());
        }
        Assert.assertEquals(resultElements.hasNext(), expectedElements.hasNext());
      }
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testJoin() {
      List<List<Tuple2<String, String>>> stringStringKVStream1 = Arrays.asList(
          Arrays.asList(new Tuple2<>("california", "dodgers"),
                        new Tuple2<>("new york", "yankees")),
          Arrays.asList(new Tuple2<>("california", "sharks"),
                        new Tuple2<>("new york", "rangers")));
  
      List<List<Tuple2<String, String>>> stringStringKVStream2 = Arrays.asList(
          Arrays.asList(new Tuple2<>("california", "giants"),
                        new Tuple2<>("new york", "mets")),
          Arrays.asList(new Tuple2<>("california", "ducks"),
                        new Tuple2<>("new york", "islanders")));
  
  
      List<List<Tuple2<String, Tuple2<String, String>>>> expected = Arrays.asList(
          Arrays.asList(
              new Tuple2<>("california",
                           new Tuple2<>("dodgers", "giants")),
              new Tuple2<>("new york",
                           new Tuple2<>("yankees", "mets"))),
          Arrays.asList(
              new Tuple2<>("california",
                           new Tuple2<>("sharks", "ducks")),
              new Tuple2<>("new york",
                           new Tuple2<>("rangers", "islanders"))));
  
  
      JavaDStream<Tuple2<String, String>> stream1 = JavaTestUtils.attachTestInputStream(
          ssc, stringStringKVStream1, 1);
      JavaPairDStream<String, String> pairStream1 = JavaPairDStream.fromJavaDStream(stream1);
  
      JavaDStream<Tuple2<String, String>> stream2 = JavaTestUtils.attachTestInputStream(
          ssc, stringStringKVStream2, 1);
      JavaPairDStream<String, String> pairStream2 = JavaPairDStream.fromJavaDStream(stream2);
  
      JavaPairDStream<String, Tuple2<String, String>> joined = pairStream1.join(pairStream2);
      JavaTestUtils.attachTestOutputStream(joined);
      List<List<Tuple2<String, Tuple2<String, String>>>> result = JavaTestUtils.runStreams(ssc, 2, 2);
  
      Assert.assertEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testLeftOuterJoin() {
      List<List<Tuple2<String, String>>> stringStringKVStream1 = Arrays.asList(
          Arrays.asList(new Tuple2<>("california", "dodgers"),
                        new Tuple2<>("new york", "yankees")),
          Arrays.asList(new Tuple2<>("california", "sharks") ));
  
      List<List<Tuple2<String, String>>> stringStringKVStream2 = Arrays.asList(
          Arrays.asList(new Tuple2<>("california", "giants") ),
          Arrays.asList(new Tuple2<>("new york", "islanders") )
  
      );
  
      List<List<Long>> expected = Arrays.asList(Arrays.asList(2L), Arrays.asList(1L));
  
      JavaDStream<Tuple2<String, String>> stream1 = JavaTestUtils.attachTestInputStream(
          ssc, stringStringKVStream1, 1);
      JavaPairDStream<String, String> pairStream1 = JavaPairDStream.fromJavaDStream(stream1);
  
      JavaDStream<Tuple2<String, String>> stream2 = JavaTestUtils.attachTestInputStream(
          ssc, stringStringKVStream2, 1);
      JavaPairDStream<String, String> pairStream2 = JavaPairDStream.fromJavaDStream(stream2);
  
      JavaPairDStream<String, Tuple2<String, Optional<String>>> joined =
          pairStream1.leftOuterJoin(pairStream2);
      JavaDStream<Long> counted = joined.count();
      JavaTestUtils.attachTestOutputStream(counted);
      List<List<Long>> result = JavaTestUtils.runStreams(ssc, 2, 2);
  
      Assert.assertEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testCheckpointMasterRecovery() throws InterruptedException {
      List<List<String>> inputData = Arrays.asList(
          Arrays.asList("this", "is"),
          Arrays.asList("a", "test"),
          Arrays.asList("counting", "letters"));
  
      List<List<Integer>> expectedInitial = Arrays.asList(
          Arrays.asList(4,2));
      List<List<Integer>> expectedFinal = Arrays.asList(
          Arrays.asList(1,4),
          Arrays.asList(8,7));
  
      File tempDir = Files.createTempDir();
      tempDir.deleteOnExit();
      ssc.checkpoint(tempDir.getAbsolutePath());
  
      JavaDStream<String> stream = JavaCheckpointTestUtils.attachTestInputStream(ssc, inputData, 1);
      JavaDStream<Integer> letterCount = stream.map(new Function<String, Integer>() {
        @Override
        public Integer call(String s) {
          return s.length();
        }
      });
      JavaCheckpointTestUtils.attachTestOutputStream(letterCount);
      List<List<Integer>> initialResult = JavaTestUtils.runStreams(ssc, 1, 1);
  
      assertOrderInvariantEquals(expectedInitial, initialResult);
      Thread.sleep(1000);
      ssc.stop();
  
      ssc = new JavaStreamingContext(tempDir.getAbsolutePath());
      // Tweak to take into consideration that the last batch before failure
      // will be re-processed after recovery
      List<List<Integer>> finalResult = JavaCheckpointTestUtils.runStreams(ssc, 2, 3);
      assertOrderInvariantEquals(expectedFinal, finalResult.subList(1, 3));
      Utils.deleteRecursively(tempDir);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testContextGetOrCreate() throws InterruptedException {
      ssc.stop();
  
      final SparkConf conf = new SparkConf()
          .setMaster("local[2]")
          .setAppName("test")
          .set("newContext", "true");
  
      File emptyDir = Files.createTempDir();
      emptyDir.deleteOnExit();
      StreamingContextSuite contextSuite = new StreamingContextSuite();
      String corruptedCheckpointDir = contextSuite.createCorruptedCheckpoint();
      String checkpointDir = contextSuite.createValidCheckpoint();
  
      // Function to create JavaStreamingContext without any output operations
      // (used to detect the new context)
      final AtomicBoolean newContextCreated = new AtomicBoolean(false);
      Function0<JavaStreamingContext> creatingFunc = new Function0<JavaStreamingContext>() {
        @Override
        public JavaStreamingContext call() {
          newContextCreated.set(true);
          return new JavaStreamingContext(conf, Seconds.apply(1));
        }
      };
  
      newContextCreated.set(false);
      ssc = JavaStreamingContext.getOrCreate(emptyDir.getAbsolutePath(), creatingFunc);
      Assert.assertTrue("new context not created", newContextCreated.get());
      ssc.stop();
  
      newContextCreated.set(false);
      ssc = JavaStreamingContext.getOrCreate(corruptedCheckpointDir, creatingFunc,
          new Configuration(), true);
      Assert.assertTrue("new context not created", newContextCreated.get());
      ssc.stop();
  
      newContextCreated.set(false);
      ssc = JavaStreamingContext.getOrCreate(checkpointDir, creatingFunc,
          new Configuration());
      Assert.assertTrue("old context not recovered", !newContextCreated.get());
      ssc.stop();
  
      newContextCreated.set(false);
      JavaSparkContext sc = new JavaSparkContext(conf);
      ssc = JavaStreamingContext.getOrCreate(checkpointDir, creatingFunc,
          new Configuration());
      Assert.assertTrue("old context not recovered", !newContextCreated.get());
      ssc.stop();
    }
  
    /* TEST DISABLED: Pending a discussion about checkpoint() semantics with TD
    @SuppressWarnings("unchecked")
    @Test
    public void testCheckpointofIndividualStream() throws InterruptedException {
      List<List<String>> inputData = Arrays.asList(
          Arrays.asList("this", "is"),
          Arrays.asList("a", "test"),
          Arrays.asList("counting", "letters"));
  
      List<List<Integer>> expected = Arrays.asList(
          Arrays.asList(4,2),
          Arrays.asList(1,4),
          Arrays.asList(8,7));
  
      JavaDStream stream = JavaCheckpointTestUtils.attachTestInputStream(ssc, inputData, 1);
      JavaDStream letterCount = stream.map(new Function<String, Integer>() {
        @Override
        public Integer call(String s) {
          return s.length();
        }
      });
      JavaCheckpointTestUtils.attachTestOutputStream(letterCount);
  
      letterCount.checkpoint(new Duration(1000));
  
      List<List<Integer>> result1 = JavaCheckpointTestUtils.runStreams(ssc, 3, 3);
      assertOrderInvariantEquals(expected, result1);
    }
    */
  
    // Input stream tests. These mostly just test that we can instantiate a given InputStream with
    // Java arguments and assign it to a JavaDStream without producing type errors. Testing of the
    // InputStream functionality is deferred to the existing Scala tests.
    @Test
    public void testSocketTextStream() {
      ssc.socketTextStream("localhost", 12345);
    }
  
    @Test
    public void testSocketString() {
      ssc.socketStream(
        "localhost",
        12345,
        new Function<InputStream, Iterable<String>>() {
          @Override
          public Iterable<String> call(InputStream in) throws IOException {
            List<String> out = new ArrayList<>();
            try (BufferedReader reader = new BufferedReader(
                new InputStreamReader(in, StandardCharsets.UTF_8))) {
              for (String line; (line = reader.readLine()) != null;) {
                out.add(line);
              }
            }
            return out;
          }
        },
        StorageLevel.MEMORY_ONLY());
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testTextFileStream() throws IOException {
      File testDir = Utils.createTempDir(System.getProperty("java.io.tmpdir"), "spark");
      List<List<String>> expected = fileTestPrepare(testDir);
  
      JavaDStream<String> input = ssc.textFileStream(testDir.toString());
      JavaTestUtils.attachTestOutputStream(input);
      List<List<String>> result = JavaTestUtils.runStreams(ssc, 1, 1);
  
      assertOrderInvariantEquals(expected, result);
    }
  
    @SuppressWarnings("unchecked")
    @Test
    public void testFileStream() throws IOException {
      File testDir = Utils.createTempDir(System.getProperty("java.io.tmpdir"), "spark");
      List<List<String>> expected = fileTestPrepare(testDir);
  
      JavaPairInputDStream<LongWritable, Text> inputStream = ssc.fileStream(
        testDir.toString(),
        LongWritable.class,
        Text.class,
        TextInputFormat.class,
        new Function<Path, Boolean>() {
          @Override
          public Boolean call(Path v1) {
            return Boolean.TRUE;
          }
        },
        true);
  
      JavaDStream<String> test = inputStream.map(
        new Function<Tuple2<LongWritable, Text>, String>() {
          @Override
          public String call(Tuple2<LongWritable, Text> v1) {
            return v1._2().toString();
          }
      });
  
      JavaTestUtils.attachTestOutputStream(test);
      List<List<String>> result = JavaTestUtils.runStreams(ssc, 1, 1);
  
      assertOrderInvariantEquals(expected, result);
    }
  
    @Test
    public void testRawSocketStream() {
      ssc.rawSocketStream("localhost", 12345);
    }
  
    private static List<List<String>> fileTestPrepare(File testDir) throws IOException {
      File existingFile = new File(testDir, "0");
      Files.write("0\n", existingFile, StandardCharsets.UTF_8);
      Assert.assertTrue(existingFile.setLastModified(1000));
      Assert.assertEquals(1000, existingFile.lastModified());
      return Arrays.asList(Arrays.asList("0"));
    }
  
    @SuppressWarnings("unchecked")
    // SPARK-5795: no logic assertions, just testing that intended API invocations compile
    private void compileSaveAsJavaAPI(JavaPairDStream<LongWritable,Text> pds) {
      pds.saveAsNewAPIHadoopFiles(
          "", "", LongWritable.class, Text.class,
          org.apache.hadoop.mapreduce.lib.output.SequenceFileOutputFormat.class);
      pds.saveAsHadoopFiles(
          "", "", LongWritable.class, Text.class,
          org.apache.hadoop.mapred.SequenceFileOutputFormat.class);
      // Checks that a previous common workaround for this API still compiles
      pds.saveAsNewAPIHadoopFiles(
          "", "", LongWritable.class, Text.class,
          (Class) org.apache.hadoop.mapreduce.lib.output.SequenceFileOutputFormat.class);
      pds.saveAsHadoopFiles(
          "", "", LongWritable.class, Text.class,
          (Class) org.apache.hadoop.mapred.SequenceFileOutputFormat.class);
    }
  
  }
  