/*
* 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.connectors.twitter;
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.util.Collector;
import org.apache.sling.commons.json.JSONException;
/**
* This program demonstrate the use of TwitterSource.
* Its aim is to count the frequency of the languages of tweets
*/
public class TwitterLocal {
private static final int PARALLELISM = 1;
private static final int SOURCE_PARALLELISM = 1;
private static final int NUMBEROFTWEETS = 100;
/**
* FlatMapFunction to determine the language of tweets if possible
*/
public static class SelectLanguageFlatMap 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{
out.collect(getString(value, "lang"));
}
catch (JSONException e){
out.collect("");
}
}
}
public static void main(String[] args) throws Exception {
String path = new String();
if (args != null && args.length == 1) {
path = args[0];
} else {
System.err.println("USAGE:\nTwitterLocal <pathToPropertiesFile>");
return;
}
StreamExecutionEnvironment env = StreamExecutionEnvironment
.createLocalEnvironment(PARALLELISM);
DataStream<String> streamSource = env.addSource(new TwitterSource(path, NUMBEROFTWEETS),
SOURCE_PARALLELISM);
DataStream<Tuple2<String, Integer>> dataStream = streamSource
.flatMap(new SelectLanguageFlatMap())
.partitionBy(0)
.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);
}
})
.groupBy(0)
.sum(1);
dataStream.print();
env.execute();
}
}