/**
* 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.mock;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.mapreduce.Counters;
import org.apache.hadoop.mapreduce.InputSplit;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.TaskAttemptID;
import org.apache.hadoop.mrunit.types.Pair;
import org.apache.hadoop.mrunit.mock.MockOutputCollector;
import java.io.IOException;
import java.util.Iterator;
import java.util.List;
/**
* o.a.h.mapreduce.Mapper.map() expects to use a Mapper.Context
* object as a parameter. We want to override the functionality
* of a lot of Context to have it send the results back to us, etc.
* But since Mapper.Context is an inner class of Mapper, we need to
* put any subclasses of Mapper.Context in a subclass of Mapper.
*
* This wrapper class exists for that purpose.
*/
public class MockMapContextWrapper<KEYIN, VALUEIN, KEYOUT, VALUEOUT>
extends Mapper<KEYIN, VALUEIN, KEYOUT, VALUEOUT> {
public static final Log LOG = LogFactory.getLog(MockMapContextWrapper.class);
/**
* Mock context instance that provides input to and receives output from
* the Mapper instance under test.
*/
public class MockMapContext extends Mapper<KEYIN, VALUEIN, KEYOUT, VALUEOUT>.Context {
private Iterator<Pair<KEYIN, VALUEIN>> inputIter;
private Pair<KEYIN, VALUEIN> curInput;
private MockOutputCollector<KEYOUT, VALUEOUT> output;
/**
* Create a new instance with the passed configuration, map key/value input
* pairs and counters
*
* @param configuration Configuration for the mapper
* @param in input key/value pairs for the mapper
* @param counters pre-initialized counter values
*/
public MockMapContext(final Configuration configuration,
final List<Pair<KEYIN, VALUEIN>> in,
final Counters counters) throws IOException, InterruptedException {
super(configuration,
new TaskAttemptID("mrunit-jt", 0, true, 0, 0),
null, null, new MockOutputCommitter(), new MockReporter(counters), null);
this.inputIter = in.iterator();
this.output = new MockOutputCollector<KEYOUT, VALUEOUT>();
}
/**
* Create a new instance with the passed map key/value input pairs and
* counters. A new {@link Configuration} object will be created and used
* to configure the mapper
*
* @param in input key/value pairs for the mapper
* @param counters pre-initialized counter values
*/
public MockMapContext(final List<Pair<KEYIN, VALUEIN>> in,
final Counters counters)
throws IOException, InterruptedException {
this(new Configuration(), in, counters);
}
@Override
public InputSplit getInputSplit() {
return new MockInputSplit();
}
@Override
public KEYIN getCurrentKey() {
return curInput.getFirst();
}
@Override
public VALUEIN getCurrentValue() {
return curInput.getSecond();
}
@Override
public boolean nextKeyValue() throws IOException {
if (this.inputIter.hasNext()) {
this.curInput = this.inputIter.next();
return true;
} else {
return false;
}
}
public void write(KEYOUT key, VALUEOUT value) throws IOException {
output.collect(key, value);
}
@Override
/** This method does nothing in the mock version. */
public void progress() {
}
@Override
/** This method does nothing in the mock version. */
public void setStatus(String status) {
}
/**
* @return the outputs from the MockOutputCollector back to
* the test harness.
*/
public List<Pair<KEYOUT, VALUEOUT>> getOutputs() {
return output.getOutputs();
}
}
public MockMapContext getMockContext(Configuration configuration,
List<Pair<KEYIN, VALUEIN>> inputs, Counters counters)
throws IOException, InterruptedException {
return new MockMapContext(configuration, inputs, counters);
}
public MockMapContext getMockContext(
List<Pair<KEYIN, VALUEIN>> inputs, Counters counters)
throws IOException, InterruptedException {
return new MockMapContext(inputs, counters);
}
}