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/*
* 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.LinkedList;
import java.util.List;
import java.util.Queue;
import scala.Tuple2;
import com.google.common.collect.Lists;
import org.apache.spark.SparkConf;
import org.apache.spark.api.java.JavaRDD;
import org.apache.spark.api.java.function.Function2;
import org.apache.spark.api.java.function.PairFunction;
import org.apache.spark.streaming.Duration;
import org.apache.spark.streaming.api.java.JavaDStream;
import org.apache.spark.streaming.api.java.JavaPairDStream;
import org.apache.spark.streaming.api.java.JavaStreamingContext;
public final class JavaQueueStream {
private JavaQueueStream() {
}
public static void main(String[] args) throws Exception {
StreamingExamples.setStreamingLogLevels();
SparkConf sparkConf = new SparkConf().setAppName("JavaQueueStream");
// Create the context
JavaStreamingContext ssc = new JavaStreamingContext(sparkConf, new Duration(1000));
// Create the queue through which RDDs can be pushed to
// a QueueInputDStream
Queue<JavaRDD<Integer>> rddQueue = new LinkedList<>();
// Create and push some RDDs into the queue
List<Integer> list = Lists.newArrayList();
for (int i = 0; i < 1000; i++) {
list.add(i);
}
for (int i = 0; i < 30; i++) {
rddQueue.add(ssc.sparkContext().parallelize(list));
}
// Create the QueueInputDStream and use it do some processing
JavaDStream<Integer> inputStream = ssc.queueStream(rddQueue);
JavaPairDStream<Integer, Integer> mappedStream = inputStream.mapToPair(
new PairFunction<Integer, Integer, Integer>() {
@Override
public Tuple2<Integer, Integer> call(Integer i) {
return new Tuple2<>(i % 10, 1);
}
});
JavaPairDStream<Integer, Integer> reducedStream = mappedStream.reduceByKey(
new Function2<Integer, Integer, Integer>() {
@Override
public Integer call(Integer i1, Integer i2) {
return i1 + i2;
}
});
reducedStream.print();
ssc.start();
ssc.awaitTermination();
}
}
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