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* 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.test.hadoopcompatibility.mapred;
import java.io.IOException;
import java.util.Iterator;
import org.apache.flink.api.common.functions.MapFunction;
import org.apache.flink.api.java.DataSet;
import org.apache.flink.api.java.ExecutionEnvironment;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.hadoopcompatibility.mapred.HadoopReduceCombineFunction;
import org.apache.flink.hadoopcompatibility.mapred.HadoopReduceFunction;
import org.apache.flink.test.util.MultipleProgramsTestBase;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.Reducer;
import org.apache.hadoop.mapred.Reporter;
import org.hamcrest.core.IsEqual;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.TemporaryFolder;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;
@RunWith(Parameterized.class)
public class HadoopReduceCombineFunctionITCase extends MultipleProgramsTestBase {
public HadoopReduceCombineFunctionITCase(TestExecutionMode mode){
super(mode);
}
@Rule
public TemporaryFolder tempFolder = new TemporaryFolder();
@Test
public void testStandardCountingWithCombiner() throws Exception{
final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
DataSet<Tuple2<IntWritable, IntWritable>> ds = HadoopTestData.getKVPairDataSet(env).
map(new Mapper1());
DataSet<Tuple2<IntWritable, IntWritable>> counts = ds.
groupBy(0).
reduceGroup(new HadoopReduceCombineFunction<IntWritable, IntWritable, IntWritable, IntWritable>(
new SumReducer(), new SumReducer()));
String resultPath = tempFolder.newFile().toURI().toString();
counts.writeAsText(resultPath);
env.execute();
String expected = "(0,5)\n"+
"(1,6)\n" +
"(2,6)\n" +
"(3,4)\n";
compareResultsByLinesInMemory(expected, resultPath);
}
@Test
public void testUngroupedHadoopReducer() throws Exception {
final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
DataSet<Tuple2<IntWritable, IntWritable>> ds = HadoopTestData.getKVPairDataSet(env).
map(new Mapper2());
DataSet<Tuple2<IntWritable, IntWritable>> sum = ds.
reduceGroup(new HadoopReduceCombineFunction<IntWritable, IntWritable, IntWritable, IntWritable>(
new SumReducer(), new SumReducer()));
String resultPath = tempFolder.newFile().toURI().toString();
sum.writeAsText(resultPath);
env.execute();
String expected = "(0,231)\n";
compareResultsByLinesInMemory(expected, resultPath);
}
@Test
public void testCombiner() throws Exception {
org.junit.Assume.assumeThat(mode, new IsEqual<TestExecutionMode>(TestExecutionMode.CLUSTER));
final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
DataSet<Tuple2<IntWritable, IntWritable>> ds = HadoopTestData.getKVPairDataSet(env).
map(new Mapper3());
DataSet<Tuple2<IntWritable, IntWritable>> counts = ds.
groupBy(0).
reduceGroup(new HadoopReduceCombineFunction<IntWritable, IntWritable, IntWritable, IntWritable>(
new SumReducer(), new KeyChangingReducer()));
String resultPath = tempFolder.newFile().toURI().toString();
counts.writeAsText(resultPath);
env.execute();
String expected = "(0,5)\n"+
"(1,6)\n" +
"(2,5)\n" +
"(3,5)\n";
compareResultsByLinesInMemory(expected, resultPath);
}
@Test
public void testConfigurationViaJobConf() throws Exception {
final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
JobConf conf = new JobConf();
conf.set("my.cntPrefix", "Hello");
DataSet<Tuple2<IntWritable, Text>> ds = HadoopTestData.getKVPairDataSet(env).
map(new Mapper4());
DataSet<Tuple2<IntWritable, IntWritable>> hellos = ds.
groupBy(0).
reduceGroup(new HadoopReduceFunction<IntWritable, Text, IntWritable, IntWritable>(
new ConfigurableCntReducer(), conf));
String resultPath = tempFolder.newFile().toURI().toString();
hellos.writeAsText(resultPath);
env.execute();
// return expected result
String expected = "(0,0)\n"+
"(1,0)\n" +
"(2,1)\n" +
"(3,1)\n" +
"(4,1)\n";
compareResultsByLinesInMemory(expected, resultPath);
}
public static class SumReducer implements Reducer<IntWritable, IntWritable, IntWritable, IntWritable> {
@Override
public void reduce(IntWritable k, Iterator<IntWritable> v, OutputCollector<IntWritable, IntWritable> out, Reporter r)
throws IOException {
int sum = 0;
while(v.hasNext()) {
sum += v.next().get();
}
out.collect(k, new IntWritable(sum));
}
@Override
public void configure(JobConf arg0) { }
@Override
public void close() throws IOException { }
}
public static class KeyChangingReducer implements Reducer<IntWritable, IntWritable, IntWritable, IntWritable> {
@Override
public void reduce(IntWritable k, Iterator<IntWritable> v, OutputCollector<IntWritable, IntWritable> out, Reporter r)
throws IOException {
while(v.hasNext()) {
out.collect(new IntWritable(k.get() % 4), v.next());
}
}
@Override
public void configure(JobConf arg0) { }
@Override
public void close() throws IOException { }
}
public static class ConfigurableCntReducer implements Reducer<IntWritable, Text, IntWritable, IntWritable> {
private String countPrefix;
@Override
public void reduce(IntWritable k, Iterator<Text> vs, OutputCollector<IntWritable, IntWritable> out, Reporter r)
throws IOException {
int commentCnt = 0;
while(vs.hasNext()) {
String v = vs.next().toString();
if(v.startsWith(this.countPrefix)) {
commentCnt++;
}
}
out.collect(k, new IntWritable(commentCnt));
}
@Override
public void configure(final JobConf c) {
this.countPrefix = c.get("my.cntPrefix");
}
@Override
public void close() throws IOException { }
}
public static class Mapper1 implements MapFunction<Tuple2<IntWritable, Text>, Tuple2<IntWritable,
IntWritable>> {
private static final long serialVersionUID = 1L;
Tuple2<IntWritable,IntWritable> outT = new Tuple2<IntWritable,IntWritable>();
@Override
public Tuple2<IntWritable, IntWritable> map(Tuple2<IntWritable, Text> v)
throws Exception {
outT.f0 = new IntWritable(v.f0.get() / 6);
outT.f1 = new IntWritable(1);
return outT;
}
}
public static class Mapper2 implements MapFunction<Tuple2<IntWritable, Text>, Tuple2<IntWritable,
IntWritable>> {
private static final long serialVersionUID = 1L;
Tuple2<IntWritable,IntWritable> outT = new Tuple2<IntWritable,IntWritable>();
@Override
public Tuple2<IntWritable, IntWritable> map(Tuple2<IntWritable, Text> v)
throws Exception {
outT.f0 = new IntWritable(0);
outT.f1 = v.f0;
return outT;
}
}
public static class Mapper3 implements MapFunction<Tuple2<IntWritable, Text>, Tuple2<IntWritable, IntWritable>> {
private static final long serialVersionUID = 1L;
Tuple2<IntWritable,IntWritable> outT = new Tuple2<IntWritable,IntWritable>();
@Override
public Tuple2<IntWritable, IntWritable> map(Tuple2<IntWritable, Text> v)
throws Exception {
outT.f0 = v.f0;
outT.f1 = new IntWritable(1);
return outT;
}
}
public static class Mapper4 implements MapFunction<Tuple2<IntWritable, Text>, Tuple2<IntWritable, Text>> {
private static final long serialVersionUID = 1L;
@Override
public Tuple2<IntWritable, Text> map(Tuple2<IntWritable, Text> v)
throws Exception {
v.f0 = new IntWritable(v.f0.get() % 5);
return v;
}
}
}