/**
* 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;
import static org.apache.hadoop.mrunit.internal.util.ArgumentChecker.returnNonNull;
import java.io.IOException;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.mapred.Counters;
import org.apache.hadoop.mapred.InputFormat;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.OutputFormat;
import org.apache.hadoop.mapred.Reducer;
import org.apache.hadoop.mrunit.internal.counters.CounterWrapper;
import org.apache.hadoop.mrunit.internal.mapred.MockReporter;
import org.apache.hadoop.mrunit.internal.output.OutputCollectable;
import org.apache.hadoop.mrunit.types.Pair;
import org.apache.hadoop.util.ReflectionUtils;
/**
* Harness that allows you to test a Reducer instance. You provide a key and a
* set of intermediate values for that key that represent inputs that should be
* sent to the Reducer (as if they came from a Mapper), and outputs you expect
* to be sent by the Reducer to the collector. By calling runTest(), the harness
* will deliver the input to the Reducer and will check its outputs against the
* expected results.
*/
public class ReduceDriver<K1, V1, K2, V2> extends
ReduceDriverBase<K1, V1, K2, V2, ReduceDriver<K1, V1, K2, V2>> {
public static final Log LOG = LogFactory.getLog(ReduceDriver.class);
private Reducer<K1, V1, K2, V2> myReducer;
private Counters counters;
public ReduceDriver(final Reducer<K1, V1, K2, V2> r) {
this();
setReducer(r);
}
public ReduceDriver() {
setCounters(new Counters());
}
/** @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(ctrs);
}
/** Sets the counters to use and returns self for fluent style */
public ReduceDriver<K1, V1, K2, V2> withCounters(final Counters ctrs) {
setCounters(ctrs);
return this;
}
/**
* Sets the reducer object to use for this test
*
* @param r
* The reducer object to use
*/
public void setReducer(final Reducer<K1, V1, K2, V2> r) {
myReducer = returnNonNull(r);
}
/**
* Identical to setReducer(), but with fluent programming style
*
* @param r
* The Reducer to use
* @return this
*/
public ReduceDriver<K1, V1, K2, V2> withReducer(
final Reducer<K1, V1, K2, V2> r) {
setReducer(r);
return this;
}
public Reducer<K1, V1, K2, V2> getReducer() {
return myReducer;
}
/**
* 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 ReduceDriver<K1, V1, K2, V2> withOutputFormat(
final Class<? extends OutputFormat> outputFormatClass,
final Class<? extends InputFormat> inputFormatClass) {
mockOutputCreator.setMapredFormats(outputFormatClass, inputFormatClass);
return this;
}
@Override
public List<Pair<K2, V2>> run() throws IOException {
try {
preRunChecks(myReducer);
initDistributedCache();
final OutputCollectable<K2, V2> outputCollectable = mockOutputCreator
.createMapredOutputCollectable(getConfiguration(),
getOutputSerializationConfiguration());
final MockReporter reporter = new MockReporter(
MockReporter.ReporterType.Reducer, getCounters());
ReflectionUtils.setConf(myReducer, new JobConf(getConfiguration()));
for (Pair<K1, List<V1>> kv : inputs) {
myReducer.reduce(kv.getFirst(), kv.getSecond().iterator(),
outputCollectable, reporter);
}
myReducer.close();
return outputCollectable.getOutputs();
} finally {
cleanupDistributedCache();
}
}
@Override
public String toString() {
return "ReduceDriver (" + myReducer + ")";
}
/**
* Returns a new ReduceDriver without having to specify the generic types on
* the right hand side of the object create statement.
*
* @return new ReduceDriver
*/
public static <K1, V1, K2, V2> ReduceDriver<K1, V1, K2, V2> newReduceDriver() {
return new ReduceDriver<K1, V1, K2, V2>();
}
/**
* Returns a new ReduceDriver without having to specify the generic types on
* the right hand side of the object create statement.
*
*
* @param reducer
* passed to ReduceDriver constructor
* @return new ReduceDriver
*/
public static <K1, V1, K2, V2> ReduceDriver<K1, V1, K2, V2> newReduceDriver(
final Reducer<K1, V1, K2, V2> reducer) {
return new ReduceDriver<K1, V1, K2, V2>(reducer);
}
}