org.apache.hadoop.mrunit

Class ReduceDriver<K1,V1,K2,V2>

java.lang.Object

org.apache.hadoop.mrunit.TestDriver<K2,V2,T>

org.apache.hadoop.mrunit.ReduceDriverBase<K1,V1,K2,V2,ReduceDriver<K1,V1,K2,V2>>

org.apache.hadoop.mrunit.ReduceDriver<K1,V1,K2,V2>

public class ReduceDriver<K1,V1,K2,V2>
extends ReduceDriverBase<K1,V1,K2,V2,ReduceDriver<K1,V1,K2,V2>>

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.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.hadoop.mrunit.ReduceDriverBase

ReduceDriverBase.ValueClassInstanceReuseList<T>

Field Summary

Fields

Modifier and Type	Field and Description
static org.apache.commons.logging.Log	LOG

Fields inherited from class org.apache.hadoop.mrunit.ReduceDriverBase

inputKey, inputs, mockOutputCreator

Fields inherited from class org.apache.hadoop.mrunit.TestDriver

counterWrapper, expectedEnumCounters, expectedMultipleOutputs, expectedOutputs, expectedPathOutputs, expectedStringCounters, mos

Constructor Summary

Constructors

Constructor and Description
ReduceDriver()
ReduceDriver(org.apache.hadoop.mapred.Reducer<K1,V1,K2,V2> r)

Method Summary

Methods

Modifier and Type	Method and Description
org.apache.hadoop.mapred.Counters	getCounters()
org.apache.hadoop.mapred.Reducer<K1,V1,K2,V2>	getReducer()
static <K1,V1,K2,V2> ReduceDriver<K1,V1,K2,V2>	newReduceDriver() Returns a new ReduceDriver without having to specify the generic types on the right hand side of the object create statement.
static <K1,V1,K2,V2> ReduceDriver<K1,V1,K2,V2>	newReduceDriver(org.apache.hadoop.mapred.Reducer<K1,V1,K2,V2> reducer) Returns a new ReduceDriver without having to specify the generic types on the right hand side of the object create statement.
List<Pair<K2,V2>>	run() Runs the test but returns the result set instead of validating it (ignores any addOutput(), etc calls made before this)
void	setCounters(org.apache.hadoop.mapred.Counters ctrs) Sets the counters object to use for this test.
void	setReducer(org.apache.hadoop.mapred.Reducer<K1,V1,K2,V2> r) Sets the reducer object to use for this test
String	toString()
ReduceDriver<K1,V1,K2,V2>	withCounters(org.apache.hadoop.mapred.Counters ctrs) Sets the counters to use and returns self for fluent style
ReduceDriver<K1,V1,K2,V2>	withOutputFormat(Class<? extends org.apache.hadoop.mapred.OutputFormat> outputFormatClass, Class<? extends org.apache.hadoop.mapred.InputFormat> inputFormatClass) Configure Reducer to output with a real OutputFormat.
ReduceDriver<K1,V1,K2,V2>	withReducer(org.apache.hadoop.mapred.Reducer<K1,V1,K2,V2> r) Identical to setReducer(), but with fluent programming style

Methods inherited from class org.apache.hadoop.mrunit.ReduceDriverBase

addAll, addInput, addInput, addInputValue, addInputValues, clearInput, getInputValues, getInputValues, preRunChecks, printPreTestDebugLog, setInput, setInputFromString, setInputKey, setInputValues, withAll, withInput, withInput, withInputFromString, withInputKey, withInputValue, withInputValues

Methods inherited from class org.apache.hadoop.mrunit.TestDriver

addAllOutput, addCacheArchive, addCacheArchive, addCacheFile, addCacheFile, addMultiOutput, addMultiOutput, addOutput, addOutput, addOutputFromString, cleanupDistributedCache, copy, copyPair, driverReused, formatPairList, formatValueList, getConfiguration, getExpectedEnumCounters, getExpectedOutputs, getExpectedStringCounters, getKeyComparator, getOutputSerializationConfiguration, getValueComparator, initDistributedCache, parseCommaDelimitedList, parseTabbedPair, resetExpectedCounters, resetOutput, run, runTest, runTest, setCacheArchives, setCacheFiles, setConfiguration, setKeyComparator, setOutputSerializationConfiguration, setUsedOnceStatus, setValueComparator, thisAsTestDriver, validate, validate, validate, validateOutputList, withAllOutput, withCacheArchive, withCacheArchive, withCacheFile, withCacheFile, withConfiguration, withCounter, withCounter, withMultiOutput, withMultiOutput, withOutput, withOutput, withOutputFromString, withOutputSerializationConfiguration, withPathOutput, withPathOutput, withStrictCounterChecking

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

LOG

public static final org.apache.commons.logging.Log LOG

Constructor Detail

ReduceDriver

public ReduceDriver(org.apache.hadoop.mapred.Reducer<K1,V1,K2,V2> r)

ReduceDriver

public ReduceDriver()

Method Detail

getCounters

public org.apache.hadoop.mapred.Counters getCounters()

Returns:

the counters used in this test

setCounters

public void setCounters(org.apache.hadoop.mapred.Counters ctrs)

Sets the counters object to use for this test.

Parameters:

ctrs - The counters object to use.

withCounters

public ReduceDriver<K1,V1,K2,V2> withCounters(org.apache.hadoop.mapred.Counters ctrs)

Sets the counters to use and returns self for fluent style

setReducer

public void setReducer(org.apache.hadoop.mapred.Reducer<K1,V1,K2,V2> r)

Sets the reducer object to use for this test

Parameters:

r - The reducer object to use

withReducer

public ReduceDriver<K1,V1,K2,V2> withReducer(org.apache.hadoop.mapred.Reducer<K1,V1,K2,V2> r)

Identical to setReducer(), but with fluent programming style

Parameters:

r - The Reducer to use

Returns:

this

getReducer

public org.apache.hadoop.mapred.Reducer<K1,V1,K2,V2> getReducer()

withOutputFormat

public ReduceDriver<K1,V1,K2,V2> withOutputFormat(Class<? extends org.apache.hadoop.mapred.OutputFormat> outputFormatClass,
                                         Class<? extends org.apache.hadoop.mapred.InputFormat> inputFormatClass)

Configure Reducer to output with a real OutputFormat. Set InputFormat to read output back in for use with run* methods

Parameters:

outputFormatClass -

inputFormatClass -

Returns:

this for fluent style

run

public List<Pair<K2,V2>> run()
                      throws IOException

Description copied from class: TestDriver

Runs the test but returns the result set instead of validating it (ignores any addOutput(), etc calls made before this)

Specified by:

run in class ReduceDriverBase<K1,V1,K2,V2,ReduceDriver<K1,V1,K2,V2>>

Returns:

the list of (k, v) pairs returned as output from the test

Throws:

IOException

toString

public String toString()

Overrides:

toString in class Object

newReduceDriver

public static <K1,V1,K2,V2> ReduceDriver<K1,V1,K2,V2> newReduceDriver()

Returns a new ReduceDriver without having to specify the generic types on the right hand side of the object create statement.

Returns:

new ReduceDriver

newReduceDriver

public static <K1,V1,K2,V2> ReduceDriver<K1,V1,K2,V2> newReduceDriver(org.apache.hadoop.mapred.Reducer<K1,V1,K2,V2> reducer)

Returns a new ReduceDriver without having to specify the generic types on the right hand side of the object create statement.

Parameters:

reducer - passed to ReduceDriver constructor

Returns:

new ReduceDriver