[FLINK-1103] [streaming] Added Twitter streaming example and default inputs for examples

flink-addons/flink-streaming/flink-streaming-connectors/pom.xml

@@ -188,6 +188,12 @@ under the License.
 			<version>2.2.0</version>
 		</dependency>
 
+		<dependency>
+			<groupId>com.google.guava</groupId>
+			<artifactId>guava</artifactId>
+			<version>18.0</version>
+		</dependency>
+
 		<dependency>
 			<groupId>org.fusesource.leveldbjni</groupId>
 			<artifactId>leveldbjni-all</artifactId>

flink-addons/flink-streaming/flink-streaming-examples/src/main/java/org/apache/flink/streaming/examples/basictopology/BasicTopology.java

@@ -18,27 +18,12 @@
 package org.apache.flink.streaming.examples.basictopology;
 
 import org.apache.flink.api.common.functions.MapFunction;
+import org.apache.flink.examples.java.wordcount.util.WordCountData;
 import org.apache.flink.streaming.api.datastream.DataStream;
 import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
-import org.apache.flink.streaming.api.function.source.SourceFunction;
-import org.apache.flink.util.Collector;
 
 public class BasicTopology {
 
-	public static class BasicSource implements SourceFunction<String> {
-
-		private static final long serialVersionUID = 1L;
-		String str = new String("streaming");
-
-		@Override
-		public void invoke(Collector<String> out) throws Exception {
-			// continuous emit
-			while (true) {
-				out.collect(str);
-			}
-		}
-	}
-
 	public static class IdentityMap implements MapFunction<String, String> {
 		private static final long serialVersionUID = 1L;
 		// map to the same value
@@ -50,14 +35,12 @@ public class BasicTopology {
 	}
 
 	private static final int PARALLELISM = 1;
-	private static final int SOURCE_PARALLELISM = 1;
 
 	public static void main(String[] args) throws Exception {
 		StreamExecutionEnvironment env = StreamExecutionEnvironment
 				.createLocalEnvironment(PARALLELISM);
 
-		DataStream<String> stream = env.addSource(new BasicSource(), SOURCE_PARALLELISM)
-				.map(new IdentityMap());
+		DataStream<String> stream = env.fromElements(WordCountData.WORDS).map(new IdentityMap());
 
 		stream.print();
 

flink-addons/flink-streaming/flink-streaming-examples/src/main/java/org/apache/flink/streaming/examples/twitter/TwitterStream.java

+/*
+ * 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.flink.streaming.examples.twitter;
+
+import java.util.StringTokenizer;
+
+import org.apache.flink.api.common.functions.FlatMapFunction;
+import org.apache.flink.api.common.functions.MapFunction;
+import org.apache.flink.api.java.tuple.Tuple2;
+import org.apache.flink.streaming.api.datastream.DataStream;
+import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
+import org.apache.flink.streaming.connectors.json.JSONParseFlatMap;
+import org.apache.flink.streaming.connectors.twitter.TwitterSource;
+import org.apache.flink.streaming.examples.twitter.util.TwitterStreamData;
+import org.apache.flink.util.Collector;
+import org.apache.sling.commons.json.JSONException;
+
+/**
+ * Implements the "TwitterStream" program that computes a most used word occurrence
+ * histogram over JSON files in a streaming fashion.
+ * 
+ * <p>
+ * The input is a JSON text file with lines separated by newline characters.
+ * 
+ * <p>
+ * Usage: <code>TwitterStream &lt;text path&gt;</code><br>
+ * If no parameters are provided, the program is run with default data from
+ * {@link TwitterStreamData}.
+ * 
+ * <p>
+ * This example shows how to:
+ * <ul>
+ * <li>write a simple Flink Streaming program.
+ * <li>use Tuple data types.
+ * <li>write and use user-defined functions.
+ * </ul>
+ * 
+ */
+public class TwitterStream {
+	private static final int PARALLELISM = 1;
+	
+	// *************************************************************************
+	// PROGRAM
+	// *************************************************************************
+	
+	public static void main(String[] args) throws Exception {
+		if (!parseParameters(args)) {
+			return;
+		}
+
+		// set up the execution environment
+		StreamExecutionEnvironment env = StreamExecutionEnvironment
+				.createLocalEnvironment(PARALLELISM);
+
+		env.setBufferTimeout(1000);
+		
+		// get input data
+		DataStream<String> streamSource = getTextDataStream(env);
+
+		DataStream<Tuple2<String, Integer>> dataStream = streamSource
+				// selecting english tweets and split to words
+				.flatMap(new SelectEnglishAndTokenizeFlatMap())
+				.partitionBy(0)
+				// returning (word, 1)
+				.map(new MapFunction<String, Tuple2<String, Integer>>() {
+					private static final long serialVersionUID = 1L;
+
+					@Override
+					public Tuple2<String, Integer> map(String value)
+							throws Exception {
+						return new Tuple2<String, Integer>(value, 1);
+					}
+				})
+				// group by words and sum their occurence
+				.groupBy(0)
+				.sum(1)
+				// select maximum occurenced word
+				.flatMap(new SelectMaxOccurence());
+
+		// emit result
+		dataStream.print();
+
+		// execute program
+		env.execute();
+	}
+	
+	// *************************************************************************
+	// USER FUNCTIONS
+	// *************************************************************************
+
+	/**
+	 * Make sentence from english tweets.
+	 * 
+	 * Implements the string tokenizer that splits sentences into words as a
+	 * user-defined FlatMapFunction. The function takes a line (String) and
+	 * splits it into multiple pairs in the form of "(word,1)" (Tuple2<String,
+	 * Integer>).
+	 */
+	public static class SelectEnglishAndTokenizeFlatMap extends
+			JSONParseFlatMap<String, String> {
+		private static final long serialVersionUID = 1L;
+
+		/**
+		 * Select the language from the incoming JSON text
+		 */
+		@Override
+		public void flatMap(String value, Collector<String> out)
+				throws Exception {
+			try {
+				if (getString(value, "lang").equals("en")) {
+					// message of tweet
+					StringTokenizer tokenizer = new StringTokenizer(getString(
+							value, "text"));
+
+					// split the message
+					while (tokenizer.hasMoreTokens()) {
+						String result = tokenizer.nextToken().replaceAll(
+								"\\s*", "");
+
+						if (result != null && !result.equals("")) {
+							out.collect(result);
+						}
+					}
+				}
+			} catch (JSONException e) {
+
+			}
+		}
+	}
+
+	/**
+	 * 
+	 * Implements a user-defined FlatMapFunction that check if the word's current occurence
+	 * is higher than the maximum occurence. If it is, return with the word and change the maximum.
+	 *
+	 */
+	public static class SelectMaxOccurence implements
+			FlatMapFunction<Tuple2<String, Integer>, Tuple2<String, Integer>> {
+		private static final long serialVersionUID = 1L;
+		private Integer maximum;
+
+		public SelectMaxOccurence() {
+			this.maximum = 0;
+		}
+
+		@Override
+		public void flatMap(Tuple2<String, Integer> value,
+				Collector<Tuple2<String, Integer>> out) throws Exception {
+			if ((Integer) value.getField(1) >= maximum) {
+				out.collect(value);
+				maximum = (Integer) value.getField(1);
+			}
+		}
+	}
+	
+	// *************************************************************************
+	// UTIL METHODS
+	// *************************************************************************
+
+	private static boolean fromFile = false;
+	private static String path;
+
+	private static boolean parseParameters(String[] args) {
+		if (args.length > 0) {
+			if (args.length == 1) {
+				fromFile = true;
+				path = args[0];
+			} else {
+				System.err.println("USAGE:\nTwitterStream <pathToPropertiesFile>");
+				return false;
+			}
+		} else {
+			System.out.println("Executing TwitterStream example with built-in default data.");
+			System.out.println("  Provide parameters to read input data from a file.");
+			System.out.println("  USAGE: TwitterStream <pathToPropertiesFile>");
+		}
+		return true;
+	}
+
+	private static DataStream<String> getTextDataStream(
+			StreamExecutionEnvironment env) {
+		if (fromFile) {
+			// read the text file from given input path
+			return env.addSource(new TwitterSource(path));
+		} else {
+			// get default test text data
+			return env.fromElements(TwitterStreamData.TEXTS);
+		}
+	}
+}