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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.
*/
// scalastyle:off println
package org.apache.spark.examples.sql.streaming
import org.apache.spark.sql.functions._
import org.apache.spark.sql.SparkSession
/**
* Counts words in UTF8 encoded, '\n' delimited text received from the network.
*
* Usage: StructuredNetworkWordCount <hostname> <port>
* <hostname> and <port> describe the TCP server that Structured Streaming
* would connect to receive data.
*
* To run this on your local machine, you need to first run a Netcat server
* `$ nc -lk 9999`
* and then run the example
* `$ bin/run-example sql.streaming.StructuredNetworkWordCount
* localhost 9999`
*/
object StructuredNetworkWordCount {
def main(args: Array[String]) {
if (args.length < 2) {
System.err.println("Usage: StructuredNetworkWordCount <hostname> <port>")
System.exit(1)
}
val host = args(0)
val port = args(1).toInt
val spark = SparkSession
.builder
.appName("StructuredNetworkWordCount")
.getOrCreate()
import spark.implicits._
// Create DataFrame representing the stream of input lines from connection to host:port
val lines = spark.readStream
.format("socket")
.option("host", host)
.option("port", port)
.load()
// Split the lines into words
val words = lines.as[String].flatMap(_.split(" "))
// Generate running word count
val wordCounts = words.groupBy("value").count()
// Start running the query that prints the running counts to the console
val query = wordCounts.writeStream
.outputMode("complete")
.format("console")
.start()
query.awaitTermination()
}
}
// scalastyle:on println
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