[SPARK-16114][SQL] structured streaming network word count examples

## What changes were proposed in this pull request?

Network word count example for structured streaming

## How was this patch tested?

Run locally

Author: James Thomas <jamesjoethomas@gmail.com>
Author: James Thomas <jamesthomas@Jamess-MacBook-Pro.local>

Closes #13816 from jjthomas/master.

1 files changed, 76 insertions, 0 deletions

diff --git a/examples/src/main/scala/org/apache/spark/examples/sql/streaming/StructuredNetworkWordCount.scala b/examples/src/main/scala/org/apache/spark/examples/sql/streaming/StructuredNetworkWordCount.scala
new file mode 100644
index 0000000000..433f7a181b
--- /dev/null
+++ b/examples/src/main/scala/org/apache/spark/examples/sql/streaming/StructuredNetworkWordCount.scala
@@ -0,0 +1,76 @@
+/*
+ * 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 every second.
+ *
+ * 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().as[String]
+
+    // Split the lines into words
+    val words = lines.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