Github user tdas commented on a diff in the pull request:
https://github.com/apache/spark/pull/1434#discussion_r15668098
--- Diff:
examples/src/main/java/org/apache/spark/examples/streaming/JavaKinesisWordCount.java
---
@@ -0,0 +1,294 @@
+/*
+ * 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.streaming;
+
+import java.util.List;
+import java.util.regex.Pattern;
+
+import org.apache.log4j.Level;
+import org.apache.log4j.Logger;
+import org.apache.spark.SparkConf;
+import org.apache.spark.api.java.JavaPairRDD;
+import org.apache.spark.api.java.function.FlatMapFunction;
+import org.apache.spark.api.java.function.Function;
+import org.apache.spark.api.java.function.Function2;
+import org.apache.spark.api.java.function.PairFunction;
+import org.apache.spark.storage.StorageLevel;
+import org.apache.spark.streaming.Duration;
+import org.apache.spark.streaming.Milliseconds;
+import org.apache.spark.streaming.api.java.JavaDStream;
+import org.apache.spark.streaming.api.java.JavaPairDStream;
+import org.apache.spark.streaming.api.java.JavaStreamingContext;
+import org.apache.spark.streaming.kinesis.KinesisRecordSerializer;
+import org.apache.spark.streaming.kinesis.KinesisStringRecordSerializer;
+import org.apache.spark.streaming.kinesis.KinesisUtils;
+
+import scala.Tuple2;
+
+import com.amazonaws.auth.DefaultAWSCredentialsProviderChain;
+import com.amazonaws.services.kinesis.AmazonKinesisClient;
+import
com.amazonaws.services.kinesis.clientlibrary.lib.worker.InitialPositionInStream;
+import com.google.common.base.Optional;
+import com.google.common.collect.Lists;
+
+/**
+ * Java-friendly Kinesis Spark Streaming WordCount example
+ *
+ * See
http://spark.apache.org/docs/latest/streaming-programming-guide.html for more
details
+ * on the Kinesis Spark Streaming integration.
+ *
+ * This example spins up 1 Kinesis Worker (Spark Streaming Receivers) per
shard
+ * of the given stream.
+ * It then starts pulling from the last checkpointed sequence number of
the given
+ * <stream-name> and <endpoint-url>.
+ *
+ * Valid endpoint urls:
http://docs.aws.amazon.com/general/latest/gr/rande.html#ak_region
+ *
+ * This code uses the DefaultAWSCredentialsProviderChain and searches for
credentials
+ * in the following order of precedence:
+ * Environment Variables - AWS_ACCESS_KEY_ID and AWS_SECRET_KEY
+ * Java System Properties - aws.accessKeyId and aws.secretKey
+ * Credential profiles file - default location
(~/.aws/credentials) shared by all AWS SDKs
+ * Instance profile credentials - delivered through the Amazon EC2
metadata service
+ *
+ * Usage: JavaKinesisWordCount <stream-name> <endpoint-url>
+ * <stream-name> is the name of the Kinesis stream (ie.
mySparkStream)
+ * <endpoint-url> is the endpoint of the Kinesis service
+ * (ie. https://kinesis.us-east-1.amazonaws.com)
+ *
+ * Example:
+ * $ export AWS_ACCESS_KEY_ID=<your-access-key>
+ * $ export AWS_SECRET_KEY=<your-secret-key>
+ * $ $SPARK_HOME/bin/run-example \
+ * org.apache.spark.examples.streaming.JavaKinesisWordCount
mySparkStream \
+ * https://kinesis.us-east-1.amazonaws.com
+ *
+ * There is a companion helper class called KinesisWordCountProducer which
puts dummy data
+ * onto the Kinesis stream.
+ * Usage instructions for KinesisWordCountProducer are provided in the
class definition.
+ */
+public final class JavaKinesisWordCount {
+ private static final Pattern WORD_SEPARATOR = Pattern.compile(" ");
+ private static final Logger logger =
Logger.getLogger(JavaKinesisWordCount.class);
+
+ /**
+ * Make the constructor private to enforce singleton
+ */
+ private JavaKinesisWordCount() {
+ }
+
+ public static void main(String[] args) {
+ /**
+ * Check that all required args were passed in.
+ */
+ if (args.length < 2) {
+ System.err.println("Usage: JavaKinesisWordCount <stream-name>
<kinesis-endpoint-url>");
+ System.exit(1);
+ }
+
+ /**
+ * (This was lifted from the StreamingExamples.scala in order to
avoid the dependency on the spark-examples artifact.)
+ * Set reasonable logging levels for streaming if the user has not
configured log4j.
+ */
+ boolean log4jInitialized = Logger.getRootLogger().getAllAppenders()
+ .hasMoreElements();
+ if (!log4jInitialized) {
+ /** We first log something to initialize Spark's default
logging, then we override the logging level. */
+ Logger.getRootLogger()
+ .info("Setting log level to [ERROR] for streaming
example."
+ + " To override add a custom log4j.properties
to the classpath.");
+ Logger.getRootLogger().setLevel(Level.ERROR);
+
Logger.getLogger("org.apache.spark.examples.streaming").setLevel(Level.DEBUG);
+ }
+
+ /** Populate the appropriate variables from the given args */
+ String stream = args[0];
+ String endpoint = args[1];
+ /** Set the batch interval to a fixed 2000 millis (2 seconds) */
+ Integer batchIntervalMillis = 2000;
+
+ /** Create a Kinesis client in order to determine the number of
shards for the given stream */
+ AmazonKinesisClient kinesisClient = new AmazonKinesisClient(
+ new DefaultAWSCredentialsProviderChain());
+ kinesisClient.setEndpoint(endpoint);
+
+ /** Determine the number of shards from the stream */
+ int numShards = kinesisClient.describeStream(stream)
+ .getStreamDescription().getShards().size();
+
+ /** In this example, we're going to create 1 Kinesis
Worker/Receiver/DStream for each shard */
+ int numStreams = numShards;
+
+ /** Must add 1 more thread than the number of receivers or the
output won't show properly from the driver */
+ int numSparkThreads = numStreams + 1;
+
+ /** Set the app name */
+ String appName = "KinesisWordCount";
+
+ /** Setup the Spark config. */
+ SparkConf sparkConfig = new
SparkConf().setAppName(appName).setMaster(
+ "local[" + numSparkThreads + "]");
+
+ /**
+ * Set the batch interval.
+ * Records will be pulled from the Kinesis stream and stored as a
single DStream within Spark every batch interval.
+ */
+ Duration batchInterval = Milliseconds.apply(batchIntervalMillis);
+
+ /**
+ * It's recommended that you perform a Spark checkpoint between 5
and 10 times the batch interval.
+ * While this is the Spark checkpoint interval, we're going to use
it for the Kinesis checkpoint interval, as well.
+ * For example purposes, we'll just use the batchInterval.
+ */
+ Duration checkpointInterval =
Milliseconds.apply(batchIntervalMillis);
+
+ /** Setup the StreamingContext */
+ JavaStreamingContext jssc = new JavaStreamingContext(sparkConfig,
batchInterval);
+
+ /** Setup the checkpoint directory used by Spark Streaming */
+ jssc.checkpoint("/tmp/checkpoint");
+
+ /** Create the same number of Kinesis Receivers/DStreams as stream
shards, then union them all */
+ JavaDStream<byte[]> allStreams = KinesisUtils
+ .createStream(jssc, appName, stream, endpoint,
checkpointInterval.milliseconds(),
+ InitialPositionInStream.LATEST);
+ /** Set the checkpoint interval */
+ allStreams.checkpoint(checkpointInterval);
+ for (int i = 1; i < numStreams; i++) {
+ /** Create a new Receiver/DStream for each stream shard */
+ JavaDStream<byte[]> dStream = KinesisUtils
+ .createStream(jssc, appName, stream, endpoint,
checkpointInterval.milliseconds(),
+ InitialPositionInStream.LATEST);
+ /** Set the Spark checkpoint interval */
+ dStream.checkpoint(checkpointInterval);
+
+ /** Union with the existing streams */
+ allStreams = allStreams.union(dStream);
+ }
+
+ /** This implementation uses the String-based
KinesisRecordSerializer impl */
+ final KinesisRecordSerializer<String> recordSerializer = new
KinesisStringRecordSerializer();
+
+ /**
+ * Split each line of the union'd DStreams into multiple words
using flatMap to produce the collection.
+ * Convert lines of byte[] to multiple Strings by first
converting to String, then splitting on WORD_SEPARATOR
+ * We're caching the result here so that we can use it later
without having to re-materialize the underlying RDDs.
+ */
+ JavaDStream<String> words = allStreams.flatMap(new
FlatMapFunction<byte[], String>() {
+ /**
+ * Convert lines of byte[] to multiple words split by
WORD_SEPARATOR
+ * @param byte array
+ * @return iterable of words split by WORD_SEPARATOR
+ */
+ @Override
+ public Iterable<String> call(byte[] line) {
+ return
Lists.newArrayList(WORD_SEPARATOR.split(recordSerializer.deserialize(line)));
+ }
+ }).cache();
+
+ /**
+ * Map each word to a (word, 1) tuple so we can reduce/aggregate
later.
+ * We're caching the result here so that we can use it later
without having
+ * to re-materialize the underlying RDDs.
+ */
+ JavaPairDStream<String, Integer> wordCounts = words.mapToPair(
+ new PairFunction<String, String, Integer>() {
+ /**
+ * Create the (word, 1) tuple
+ * @param word
+ * @return (word, 1) tuple
+ */
+ @Override
+ public Tuple2<String, Integer> call(String s) {
+ return new Tuple2<String, Integer>(s, 1);
+ }
+ });
+
+ /**
+ * Reduce/aggregate by key
+ * We're caching the result here so that we can use it later
without having
+ * to re-materialize the underlying RDDs.
+ */
+ JavaPairDStream<String, Integer> wordCountsByKey =
wordCounts.reduceByKey(
+ new Function2<Integer, Integer, Integer>() {
+ @Override
+ public Integer call(Integer i1, Integer i2) {
+ return i1 + i2;
+ }
+ }).cache();
+
+ /** Update the running totals of words. */
--- End diff --
Same comment as the other example. Needs to be simplified.
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