/***********************************************************************************************************************
* Copyright (C) 2010-2013 by the Stratosphere project (http://stratosphere.eu)
*
* Licensed 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 eu.stratosphere.test.recordJobs.wordcount;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.io.Serializable;
import java.util.Iterator;
import java.util.Set;
import java.util.StringTokenizer;
import eu.stratosphere.api.common.JobExecutionResult;
import eu.stratosphere.api.common.Plan;
import eu.stratosphere.api.common.Program;
import eu.stratosphere.api.common.ProgramDescription;
import eu.stratosphere.api.common.accumulators.Accumulator;
import eu.stratosphere.api.common.accumulators.Histogram;
import eu.stratosphere.api.common.accumulators.LongCounter;
import eu.stratosphere.api.java.record.operators.FileDataSink;
import eu.stratosphere.api.java.record.operators.FileDataSource;
import eu.stratosphere.api.java.record.functions.FunctionAnnotation.ConstantFields;
import eu.stratosphere.api.java.record.functions.MapFunction;
import eu.stratosphere.api.java.record.functions.ReduceFunction;
import eu.stratosphere.api.java.record.io.CsvOutputFormat;
import eu.stratosphere.api.java.record.io.TextInputFormat;
import eu.stratosphere.api.java.record.operators.MapOperator;
import eu.stratosphere.api.java.record.operators.ReduceOperator;
import eu.stratosphere.api.java.record.operators.ReduceOperator.Combinable;
import eu.stratosphere.client.LocalExecutor;
import eu.stratosphere.configuration.Configuration;
import eu.stratosphere.nephele.util.SerializableHashSet;
import eu.stratosphere.types.IntValue;
import eu.stratosphere.types.Record;
import eu.stratosphere.types.StringValue;
import eu.stratosphere.types.Value;
import eu.stratosphere.util.Collector;
/**
* This is similar to the WordCount example and additionally demonstrates how to
* use custom accumulators (built-in or custom).
*/
public class WordCountAccumulators implements Program, ProgramDescription {
private static final long serialVersionUID = 1L;
public static class TokenizeLine extends MapFunction implements Serializable {
private static final long serialVersionUID = 1L;
// For efficiency it is recommended to have member variables for the accumulators
public static final String ACCUM_NUM_LINES = "accumulator.num-lines";
private LongCounter numLines = new LongCounter();
// This histogram accumulator collects the distribution of number of words per line
public static final String ACCUM_WORDS_PER_LINE = "accumulator.words-per-line";
private Histogram wordsPerLine = new Histogram();
public static final String ACCUM_DISTINCT_WORDS = "accumulator.distinct-words";
private SetAccumulator<StringValue> distinctWords = new SetAccumulator<StringValue>();
@Override
public void open(Configuration parameters) throws Exception {
// Accumulators have to be registered to the system
getRuntimeContext().addAccumulator(ACCUM_NUM_LINES, this.numLines);
getRuntimeContext().addAccumulator(ACCUM_WORDS_PER_LINE, this.wordsPerLine);
getRuntimeContext().addAccumulator(ACCUM_DISTINCT_WORDS, this.distinctWords);
// You could also write to accumulators in open() or close()
}
@Override
public void map(Record record, Collector<Record> collector) {
// Increment counter
numLines.add(1L);
// get the first field (as type StringValue) from the record
String line = record.getField(0, StringValue.class).getValue();
// normalize the line
line = line.replaceAll("\\W+", " ").toLowerCase();
// tokenize the line
StringTokenizer tokenizer = new StringTokenizer(line);
int numWords = 0;
while (tokenizer.hasMoreTokens()) {
String word = tokenizer.nextToken();
distinctWords.add(new StringValue(word));
++numWords;
// we emit a (word, 1) pair
collector.collect(new Record(new StringValue(word), new IntValue(1)));
}
// Add a value to the histogram accumulator
this.wordsPerLine.add(numWords);
}
}
@Combinable
@ConstantFields(0)
public static class CountWords extends ReduceFunction implements Serializable {
private static final long serialVersionUID = 1L;
private final IntValue cnt = new IntValue();
@Override
public void reduce(Iterator<Record> records, Collector<Record> out) {
Record element = null;
int sum = 0;
while (records.hasNext()) {
element = records.next();
IntValue i = element.getField(1, IntValue.class);
sum += i.getValue();
}
this.cnt.setValue(sum);
element.setField(1, this.cnt);
out.collect(element);
}
}
@Override
public Plan getPlan(String... args) {
int numSubTasks = (args.length > 0 ? Integer.parseInt(args[0]) : 1);
String dataInput = (args.length > 1 ? args[1] : "");
String output = (args.length > 2 ? args[2] : "");
FileDataSource source = new FileDataSource(new TextInputFormat(), dataInput, "Input Lines");
MapOperator mapper = MapOperator.builder(new TokenizeLine()).input(source).name("Tokenize Lines").build();
ReduceOperator reducer = ReduceOperator.builder(CountWords.class, StringValue.class, 0).input(mapper)
.name("Count Words").build();
FileDataSink out = new FileDataSink(new CsvOutputFormat(), output, reducer, "Word Counts");
CsvOutputFormat.configureRecordFormat(out).recordDelimiter('\n')
.fieldDelimiter(' ').field(StringValue.class, 0)
.field(IntValue.class, 1);
Plan plan = new Plan(out, "WordCount Example");
plan.setDefaultParallelism(numSubTasks);
return plan;
}
@Override
public String getDescription() {
return "Parameters: [numSubStasks] [input] [output]";
}
public static void main(String[] args) throws Exception {
WordCountAccumulators wc = new WordCountAccumulators();
if (args.length < 3) {
System.err.println(wc.getDescription());
System.exit(1);
}
Plan plan = wc.getPlan(args);
JobExecutionResult result = LocalExecutor.execute(plan);
// Accumulators can be accessed by their name.
System.out.println("Number of lines counter: "+ result.getAccumulatorResult(TokenizeLine.ACCUM_NUM_LINES));
System.out.println("Words per line histogram: " + result.getAccumulatorResult(TokenizeLine.ACCUM_WORDS_PER_LINE));
System.out.println("Distinct words: " + result.getAccumulatorResult(TokenizeLine.ACCUM_DISTINCT_WORDS));
}
/**
* Custom accumulator
*/
public static class SetAccumulator<T extends Value> implements Accumulator<T, Set<T>> {
private static final long serialVersionUID = 1L;
private SerializableHashSet<T> set = new SerializableHashSet<T>();
@Override
public void add(T value) {
this.set.add(value);
}
@Override
public Set<T> getLocalValue() {
return this.set;
}
@Override
public void resetLocal() {
this.set.clear();
}
@Override
public void merge(Accumulator<T, Set<T>> other) {
// build union
this.set.addAll(((SetAccumulator<T>) other).getLocalValue());
}
@Override
public void write(DataOutput out) throws IOException {
this.set.write(out);
}
@Override
public void read(DataInput in) throws IOException {
this.set.read(in);
}
}
}