/**
* 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.*;
import java.io.IOException;
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.OutputFormat;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mrunit.ReduceDriverBase;
import org.apache.hadoop.mrunit.internal.counters.CounterWrapper;
import org.apache.hadoop.mrunit.internal.mapreduce.ContextDriver;
import org.apache.hadoop.mrunit.internal.mapreduce.MockReduceContextWrapper;
import org.apache.hadoop.mrunit.types.Pair;
/**
* 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>> implements
ContextDriver {
public static final Log LOG = LogFactory.getLog(ReduceDriver.class);
private Reducer<K1, V1, K2, V2> myReducer;
private Counters counters;
/**
* Context creator, do not use directly, always use the
* the getter as it lazily creates the object in the case
* the setConfiguration() method will be used by the user.
*/
private MockReduceContextWrapper<K1, V1, K2, V2> wrapper;
public ReduceDriver(final Reducer<K1, V1, K2, V2> r) {
this();
setReducer(r);
}
public ReduceDriver() {
setCounters(new Counters());
}
/**
* 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;
}
/** @return the counters used in this test */
@Override
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) {
this.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;
}
/**
* 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.setMapreduceFormats(outputFormatClass, inputFormatClass);
return this;
}
@Override
public List<Pair<K2, V2>> run() throws IOException {
try {
preRunChecks(myReducer);
initDistributedCache();
MockReduceContextWrapper<K1, V1, K2, V2> wrapper = getContextWrapper();
myReducer.run(wrapper.getMockContext());
return wrapper.getOutputs();
} catch (final InterruptedException ie) {
throw new IOException(ie);
} finally {
cleanupDistributedCache();
}
}
@Override
public String toString() {
return "ReduceDriver (0.20+) (" + myReducer + ")";
}
private MockReduceContextWrapper<K1, V1, K2, V2> getContextWrapper() {
if(wrapper == null) {
wrapper = new MockReduceContextWrapper<K1, V1, K2, V2>(
getConfiguration(), inputs, mockOutputCreator, this);
}
return wrapper;
}
/**
* <p>Obtain Context object for furthering mocking with Mockito.
* For example, causing write() to throw an exception:</p>
*
* <pre>
* import static org.mockito.Matchers.*;
* import static org.mockito.Mockito.*;
* doThrow(new IOException()).when(context).write(any(), any());
* </pre>
*
* <p>Or implement other logic:</p>
*
* <pre>
* import static org.mockito.Matchers.*;
* import static org.mockito.Mockito.*;
* doAnswer(new Answer<Object>() {
* public Object answer(final InvocationOnMock invocation) {
* ...
* return null;
* }
* }).when(context).write(any(), any());
* </pre>
* @return the mocked context
*/
public Reducer<K1, V1, K2, V2>.Context getContext() {
return getContextWrapper().getMockContext();
}
/**
* 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);
}
}