/**
* 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.conf.Configuration;
import org.apache.hadoop.mapreduce.Counters;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mrunit.ReduceDriverBase;
import org.apache.hadoop.mrunit.counters.CounterWrapper;
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) {
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 */
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;
}
/**
* Identical to setInputKey() but with fluent programming style
*
* @return this
*/
public ReduceDriver<K1, V1, K2, V2> withInputKey(final 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(final 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(final List<V1> values) {
addInputValues(values);
return this;
}
/**
* Identical to setInput() but returns self for fluent programming style
*
* @param key
* @param values
*
* @return this
*/
public ReduceDriver<K1, V1, K2, V2> withInput(final K1 key,
final 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(final 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(final K2 key, final 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
* @deprecated No replacement due to lack of type safety and incompatibility
* with non Text Writables
*/
@Deprecated
public ReduceDriver<K1, V1, K2, V2> withInputFromString(final 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
* @deprecated No replacement due to lack of type safety and incompatibility
* with non Text Writables
*/
@Deprecated
public ReduceDriver<K1, V1, K2, V2> withOutputFromString(final String output) {
addOutputFromString(output);
return this;
}
@Override
public List<Pair<K2, V2>> run() throws IOException {
if (inputKey == null || getInputValues().isEmpty()) {
throw new IllegalStateException("No input was provided");
}
if (myReducer == null) {
throw new IllegalStateException("No Reducer class was provided");
}
final List<Pair<K1, List<V1>>> inputs = new ArrayList<Pair<K1, List<V1>>>();
inputs.add(new Pair<K1, List<V1>>(inputKey, getInputValues()));
try {
final MockReduceContextWrapper<K1, V1, K2, V2> wrapper = new MockReduceContextWrapper<K1, V1, K2, V2>(
inputs, getCounters(), getConfiguration());
final Reducer<K1, V1, K2, V2>.Context context = wrapper.getMockContext();
myReducer.run(context);
return wrapper.getOutputs();
} catch (final 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(
final Configuration configuration) {
setConfiguration(configuration);
return this;
}
@Override
public ReduceDriver<K1, V1, K2, V2> withCounter(final Enum e,
final long expectedValue) {
super.withCounter(e, expectedValue);
return this;
}
@Override
public ReduceDriver<K1, V1, K2, V2> withCounter(final String g,
final String n, final long e) {
super.withCounter(g, n, e);
return this;
}
/**
* 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);
}
}