/**
* 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 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.conf.Configuration;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Counters;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mrunit.ReduceDriverBase;
import org.apache.hadoop.mrunit.mapreduce.mock.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. This is designed to handle a single
* (k, v*) -> (k, v)* case from the Reducer, representing a single unit test.
* Multiple input (k, v*) sets should go in separate unit tests.
*/
public class ReduceDriver<K1, V1, K2, V2> extends ReduceDriverBase<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) {
myReducer = r;
counters = new Counters();
}
public ReduceDriver() {
counters = new Counters();
}
/**
* Sets the reducer object to use for this test
*
* @param r
* The reducer object to use
*/
public void setReducer(Reducer<K1, V1, K2, V2> r) {
myReducer = r;
}
/**
* Identical to setReducer(), but with fluent programming style
*
* @param r
* The Reducer to use
* @return this
*/
public ReduceDriver<K1, V1, K2, V2> withReducer(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 */
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;
}
/** 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;
}
/**
* Identical to setInputKey() but with fluent programming style
*
* @return this
*/
public ReduceDriver<K1, V1, K2, V2> withInputKey(K1 key) {
setInputKey(key);
return this;
}
/**
* Identical to addInputValue() but with fluent programming style
*
* @param val
* @return this
*/
public ReduceDriver<K1, V1, K2, V2> withInputValue(V1 val) {
addInputValue(val);
return this;
}
/**
* Identical to addInputValues() but with fluent programming style
*
* @param values
* @return this
*/
public ReduceDriver<K1, V1, K2, V2> withInputValues(List<V1> values) {
addInputValues(values);
return this;
}
/**
* Identical to setInput() but returns self for fluent programming style
*
* @return this
*/
public ReduceDriver<K1, V1, K2, V2> withInput(K1 key, List<V1> values) {
setInput(key, values);
return this;
}
/**
* Works like addOutput(), but returns self for fluent style
*
* @param outputRecord
* @return this
*/
public ReduceDriver<K1, V1, K2, V2> withOutput(Pair<K2, V2> outputRecord) {
addOutput(outputRecord);
return this;
}
/**
* Works like addOutput(), but returns self for fluent style
*
* @param key The key part of a (k, v) pair to add
* @param val The val part of a (k, v) pair to add
* @return this
*/
public ReduceDriver<K1, V1, K2, V2> withOutput(K2 key, V2 val) {
addOutput(key, val);
return this;
}
/**
* Identical to setInput, but with a fluent programming style
*
* @param input
* A string of the form "key \t val". Trims any whitespace.
* @return this
*/
public ReduceDriver<K1, V1, K2, V2> withInputFromString(String input) {
setInputFromString(input);
return this;
}
/**
* Identical to addOutput, but with a fluent programming style
*
* @param output
* A string of the form "key \t val". Trims any whitespace.
* @return this
*/
public ReduceDriver<K1, V1, K2, V2> withOutputFromString(String output) {
addOutputFromString(output);
return this;
}
@Override
public List<Pair<K2, V2>> run() throws IOException {
List<Pair<K1, List<V1>>> inputs = new ArrayList<Pair<K1, List<V1>>>();
inputs.add(new Pair<K1, List<V1>>(inputKey, inputValues));
try {
MockReduceContextWrapper<K1, V1, K2, V2> wrapper = new MockReduceContextWrapper();
MockReduceContextWrapper<K1, V1, K2, V2>.MockReduceContext context =
wrapper.getMockContext(configuration, inputs, getCounters());
myReducer.run(context);
return context.getOutputs();
} catch (InterruptedException ie) {
throw new IOException(ie);
}
}
@Override
public String toString() {
return "ReduceDriver (0.20+) (" + myReducer + ")";
}
/**
* @param configuration The configuration object that will given to the
* reducer associated with the driver
* @return this object for fluent coding
*/
public ReduceDriver<K1, V1, K2, V2> withConfiguration(
Configuration configuration) {
setConfiguration(configuration);
return this;
}
}