/*
* 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.storm.wordcount;
import org.apache.storm.topology.IRichBolt;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.api.java.typeutils.TypeExtractor;
import org.apache.flink.examples.java.wordcount.util.WordCountData;
import org.apache.flink.storm.wordcount.operators.BoltTokenizer;
import org.apache.flink.storm.wrappers.BoltWrapper;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
/**
* Implements the "WordCount" program that computes a simple word occurrence histogram over text files in a streaming
* fashion. The tokenizer step is performed by a {@link IRichBolt Bolt}.
* <p>
* The input is a plain text file with lines separated by newline characters.
* <p>
* Usage: <code>WordCount <text path> <result path></code><br>
* If no parameters are provided, the program is run with default data from {@link WordCountData}.
* <p>
* This example shows how to:
* <ul>
* <li>use a Bolt within a Flink Streaming program.</li>
* </ul>
*/
public class BoltTokenizerWordCount {
// *************************************************************************
// PROGRAM
// *************************************************************************
public static void main(final String[] args) throws Exception {
if (!parseParameters(args)) {
return;
}
// set up the execution environment
final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
// get input data
final DataStream<String> text = getTextDataStream(env);
final DataStream<Tuple2<String, Integer>> counts = text
// split up the lines in pairs (2-tuples) containing: (word,1)
// this is done by a bolt that is wrapped accordingly
.transform("BoltTokenizer",
TypeExtractor.getForObject(new Tuple2<String, Integer>("", 0)),
new BoltWrapper<String, Tuple2<String, Integer>>(new BoltTokenizer()))
// group by the tuple field "0" and sum up tuple field "1"
.keyBy(0).sum(1);
// emit result
if (fileOutput) {
counts.writeAsText(outputPath);
} else {
counts.print();
}
// execute program
env.execute("Streaming WordCount with bolt tokenizer");
}
// *************************************************************************
// UTIL METHODS
// *************************************************************************
private static boolean fileOutput = false;
private static String textPath;
private static String outputPath;
private static boolean parseParameters(final String[] args) {
if (args.length > 0) {
// parse input arguments
fileOutput = true;
if (args.length == 2) {
textPath = args[0];
outputPath = args[1];
} else {
System.err.println("Usage: BoltTokenizerWordCount <text path> <result path>");
return false;
}
} else {
System.out.println("Executing BoltTokenizerWordCount example with built-in default data");
System.out.println(" Provide parameters to read input data from a file");
System.out.println(" Usage: BoltTokenizerWordCount <text path> <result path>");
}
return true;
}
private static DataStream<String> getTextDataStream(final StreamExecutionEnvironment env) {
if (fileOutput) {
// read the text file from given input path
return env.readTextFile(textPath);
}
return env.fromElements(WordCountData.WORDS);
}
}