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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.
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package org.apache.flink.streaming.examples.windowing;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.api.java.utils.ParameterTool;
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.examples.wordcount.WordCount;
/**
* Implements a windowed version of the streaming "WordCount" program.
*
* <p>
* The input is a plain text file with lines separated by newline characters.
*
* <p>
* Usage: <code>WordCount --input <path> --output <path> --window <n> --slide <n></code><br>
* If no parameters are provided, the program is run with default data from
* {@link org.apache.flink.examples.java.wordcount.util.WordCountData}.
*
* <p>
* This example shows how to:
* <ul>
* <li>write a simple Flink Streaming program,
* <li>use tuple data types,
* <li>use basic windowing abstractions.
* </ul>
*
*/
public class WindowWordCount {
// *************************************************************************
// PROGRAM
// *************************************************************************
public static void main(String[] args) throws Exception {
final ParameterTool params = ParameterTool.fromArgs(args);
// set up the execution environment
final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
// get input data
DataStream<String> text;
if (params.has("input")) {
// read the text file from given input path
text = env.readTextFile(params.get("input"));
} else {
System.out.println("Executing WindowWordCount example with default input data set.");
System.out.println("Use --input to specify file input.");
// get default test text data
text = env.fromElements(WordCountData.WORDS);
}
// make parameters available in the web interface
env.getConfig().setGlobalJobParameters(params);
final int windowSize = params.getInt("window", 250);
final int slideSize = params.getInt("slide", 150);
DataStream<Tuple2<String, Integer>> counts =
// split up the lines in pairs (2-tuples) containing: (word,1)
text.flatMap(new WordCount.Tokenizer())
// create windows of windowSize records slided every slideSize records
.keyBy(0)
.countWindow(windowSize, slideSize)
// group by the tuple field "0" and sum up tuple field "1"
.sum(1);
// emit result
if (params.has("output")) {
counts.writeAsText(params.get("output"));
} else {
System.out.println("Printing result to stdout. Use --output to specify output path.");
counts.print();
}
// execute program
env.execute("WindowWordCount");
}
}