/**
* 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.hadoop.mrunit.mapreduce;
import static org.apache.hadoop.mrunit.internal.util.ArgumentChecker.returnNonNull;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.mapreduce.Counters;
import org.apache.hadoop.mapreduce.InputFormat;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.OutputFormat;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mrunit.MapReduceDriverBase;
import org.apache.hadoop.mrunit.internal.counters.CounterWrapper;
import org.apache.hadoop.mrunit.types.Pair;
/**
* Harness that allows you to test a Mapper and a Reducer instance together You
* provide the input key and value that should be sent to the Mapper, and
* outputs you expect to be sent by the Reducer to the collector for those
* inputs. By calling runTest(), the harness will deliver the input to the
* Mapper, feed the intermediate results to the Reducer (without checking them),
* and will check the Reducer's outputs against the expected results. This is
* designed to handle a single (k, v)* -> (k, v)* case from the Mapper/Reducer
* pair, representing a single unit test.
*/
public class MapReduceDriver<K1, V1, K2, V2, K3, V3> extends
MapReduceDriverBase<K1, V1, K2, V2, K3, V3, MapReduceDriver<K1, V1, K2, V2, K3, V3>> {
public static final Log LOG = LogFactory.getLog(MapReduceDriver.class);
private Mapper<K1, V1, K2, V2> myMapper;
private Reducer<K2, V2, K3, V3> myReducer;
private Reducer<K2, V2, K2, V2> myCombiner;
private Counters counters;
@SuppressWarnings("rawtypes")
private Class<? extends OutputFormat> outputFormatClass;
@SuppressWarnings("rawtypes")
private Class<? extends InputFormat> inputFormatClass;
public MapReduceDriver(final Mapper<K1, V1, K2, V2> m,
final Reducer<K2, V2, K3, V3> r) {
this();
setMapper(m);
setReducer(r);
}
public MapReduceDriver(final Mapper<K1, V1, K2, V2> m,
final Reducer<K2, V2, K3, V3> r, final Reducer<K2, V2, K2, V2> c) {
this(m, r);
setCombiner(c);
}
public MapReduceDriver() {
setCounters(new Counters());
}
/**
* Set the Mapper instance to use with this test driver
*
* @param m
* the Mapper instance to use
*/
public void setMapper(final Mapper<K1, V1, K2, V2> m) {
myMapper = returnNonNull(m);
}
/** Sets the Mapper instance to use and returns self for fluent style */
public MapReduceDriver<K1, V1, K2, V2, K3, V3> withMapper(
final Mapper<K1, V1, K2, V2> m) {
setMapper(m);
return this;
}
/**
* @return the Mapper object being used by this test
*/
public Mapper<K1, V1, K2, V2> getMapper() {
return myMapper;
}
/**
* Sets the reducer object to use for this test
*
* @param r
* The reducer object to use
*/
public void setReducer(final Reducer<K2, V2, K3, V3> r) {
myReducer = returnNonNull(r);
}
/**
* Identical to setReducer(), but with fluent programming style
*
* @param r
* The Reducer to use
* @return this
*/
public MapReduceDriver<K1, V1, K2, V2, K3, V3> withReducer(
final Reducer<K2, V2, K3, V3> r) {
setReducer(r);
return this;
}
/**
* @return the Reducer object being used for this test
*/
public Reducer<K2, V2, K3, V3> getReducer() {
return myReducer;
}
/**
* Sets the reducer object to use as a combiner for this test
*
* @param c
* The combiner object to use
*/
public void setCombiner(final Reducer<K2, V2, K2, V2> c) {
myCombiner = returnNonNull(c);
}
/**
* Identical to setCombiner(), but with fluent programming style
*
* @param c
* The Combiner to use
* @return this
*/
public MapReduceDriver<K1, V1, K2, V2, K3, V3> withCombiner(
final Reducer<K2, V2, K2, V2> c) {
setCombiner(c);
return this;
}
/**
* @return the Combiner object being used for this test
*/
public Reducer<K2, V2, K2, V2> getCombiner() {
return myCombiner;
}
/** @return the counters used in this test */
public Counters getCounters() {
return counters;
}
/**
* Sets the counters object to use for this test.
*
* @param ctrs
* The counters object to use.
*/
public void setCounters(final Counters ctrs) {
counters = ctrs;
counterWrapper = new CounterWrapper(counters);
}
/** Sets the counters to use and returns self for fluent style */
public MapReduceDriver<K1, V1, K2, V2, K3, V3> withCounters(
final Counters ctrs) {
setCounters(ctrs);
return this;
}
/**
* Configure {@link Reducer} to output with a real {@link OutputFormat}. Set
* {@link InputFormat} to read output back in for use with run* methods
*
* @param outputFormatClass
* @param inputFormatClass
* @return this for fluent style
*/
@SuppressWarnings("rawtypes")
public MapReduceDriver<K1, V1, K2, V2, K3, V3> withOutputFormat(
final Class<? extends OutputFormat> outputFormatClass,
final Class<? extends InputFormat> inputFormatClass) {
this.outputFormatClass = returnNonNull(outputFormatClass);
this.inputFormatClass = returnNonNull(inputFormatClass);
return this;
}
/**
* The private class to manage starting the reduce phase is used for type
* genericity reasons. This class is used in the run() method.
*/
private class ReducePhaseRunner<OUTKEY, OUTVAL> {
private List<Pair<OUTKEY, OUTVAL>> runReduce(
final List<Pair<K2, List<V2>>> inputs,
final Reducer<K2, V2, OUTKEY, OUTVAL> reducer) throws IOException {
final List<Pair<OUTKEY, OUTVAL>> reduceOutputs = new ArrayList<Pair<OUTKEY, OUTVAL>>();
if (!inputs.isEmpty()) {
if (LOG.isDebugEnabled()) {
final StringBuilder sb = new StringBuilder();
for (Pair<K2, List<V2>> input : inputs) {
formatValueList(input.getSecond(), sb);
LOG.debug("Reducing input (" + input.getFirst() + ", " + sb + ")");
sb.delete(0, sb.length());
}
}
final ReduceDriver<K2, V2, OUTKEY, OUTVAL> reduceDriver = ReduceDriver
.newReduceDriver(reducer).withCounters(getCounters())
.withConfiguration(getConfiguration()).withAll(inputs);
if (getOutputSerializationConfiguration() != null) {
reduceDriver
.withOutputSerializationConfiguration(getOutputSerializationConfiguration());
}
if (outputFormatClass != null) {
reduceDriver.withOutputFormat(outputFormatClass, inputFormatClass);
}
reduceOutputs.addAll(reduceDriver.run());
}
return reduceOutputs;
}
}
@Override
public List<Pair<K3, V3>> run() throws IOException {
try {
preRunChecks(myMapper, myReducer);
initDistributedCache();
List<Pair<K2, V2>> mapOutputs = new ArrayList<Pair<K2, V2>>();
// run map component
LOG.debug("Starting map phase with mapper: " + myMapper);
mapOutputs.addAll(MapDriver.newMapDriver(myMapper)
.withCounters(getCounters()).withConfiguration(getConfiguration())
.withAll(inputList).withMapInputPath(getMapInputPath()).run());
if (myCombiner != null) {
// User has specified a combiner. Run this and replace the mapper outputs
// with the result of the combiner.
LOG.debug("Starting combine phase with combiner: " + myCombiner);
mapOutputs = new ReducePhaseRunner<K2, V2>().runReduce(
shuffle(mapOutputs), myCombiner);
}
// Run the reduce phase.
LOG.debug("Starting reduce phase with reducer: " + myReducer);
return new ReducePhaseRunner<K3, V3>().runReduce(shuffle(mapOutputs),
myReducer);
} finally {
cleanupDistributedCache();
}
}
@Override
public String toString() {
return "MapReduceDriver (0.20+) (" + myMapper + ", " + myReducer + ")";
}
/**
* Returns a new MapReduceDriver without having to specify the generic types
* on the right hand side of the object create statement.
*
* @return new MapReduceDriver
*/
public static <K1, V1, K2, V2, K3, V3> MapReduceDriver<K1, V1, K2, V2, K3, V3> newMapReduceDriver() {
return new MapReduceDriver<K1, V1, K2, V2, K3, V3>();
}
/**
* Returns a new MapReduceDriver without having to specify the generic types
* on the right hand side of the object create statement.
*
* @param mapper
* passed to MapReduceDriver constructor
* @param reducer
* passed to MapReduceDriver constructor
* @return new MapReduceDriver
*/
public static <K1, V1, K2, V2, K3, V3> MapReduceDriver<K1, V1, K2, V2, K3, V3> newMapReduceDriver(
final Mapper<K1, V1, K2, V2> mapper, final Reducer<K2, V2, K3, V3> reducer) {
return new MapReduceDriver<K1, V1, K2, V2, K3, V3>(mapper, reducer);
}
/**
* Returns a new MapReduceDriver without having to specify the generic types
* on the right hand side of the object create statement.
*
* @param mapper
* passed to MapReduceDriver constructor
* @param reducer
* passed to MapReduceDriver constructor
* @param combiner
* passed to MapReduceDriver constructor
* @return new MapReduceDriver
*/
public static <K1, V1, K2, V2, K3, V3> MapReduceDriver<K1, V1, K2, V2, K3, V3> newMapReduceDriver(
final Mapper<K1, V1, K2, V2> mapper,
final Reducer<K2, V2, K3, V3> reducer,
final Reducer<K2, V2, K2, V2> combiner) {
return new MapReduceDriver<K1, V1, K2, V2, K3, V3>(mapper, reducer,
combiner);
}
}