org.apache.hadoop.mrunit
Class MapReduceDriverBase<K1,V1,K2 extends Comparable,V2,K3,V3>

java.lang.Object
  org.apache.hadoop.mrunit.TestDriver<K1,V1,K3,V3>
      org.apache.hadoop.mrunit.MapReduceDriverBase<K1,V1,K2,V2,K3,V3>

Direct Known Subclasses:

MapReduceDriver, MapReduceDriver

public abstract class MapReduceDriverBase<K1,V1,K2 extends Comparable,V2,K3,V3>
extends TestDriver<K1,V1,K3,V3>

Harness that allows you to test a Mapper and a Reducer instance together You provide the input key and value that should be sent to the Mapper, and outputs you expect to be sent by the Reducer to the collector for those inputs. By calling runTest(), the harness will deliver the input to the Mapper, feed the intermediate results to the Reducer (without checking them), and will check the Reducer's outputs against the expected results. This is designed to handle a single (k, v)* -> (k, v)* case from the Mapper/Reducer pair, representing a single unit test.

Field Summary

protected List<Pair<K1,V1>>	inputList
protected Comparator<K2>	keyGroupComparator Key group comparator
protected Comparator<K2>	keyValueOrderComparator Key value order comparator
static org.apache.commons.logging.Log	LOG

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

configuration, expectedOutputs

Constructor Summary

MapReduceDriverBase()

Method Summary

void	addInput(K1 key, V1 val) Adds an input to send to the mapper
void	addInput(Pair<K1,V1> input) Adds an input to send to the Mapper
void	addInputFromString(String input) Expects an input of the form "key \t val" Forces the Mapper input types to Text.
void	addOutput(K3 key, V3 val) Adds a (k, v) pair we expect as output from the Reducer
void	addOutput(Pair<K3,V3> outputRecord) Adds an output (k, v) pair we expect from the Reducer
void	addOutputFromString(String output) Expects an input of the form "key \t val" Forces the Reducer output types to Text.
abstract List<Pair<K3,V3>>	run() Runs the test but returns the result set instead of validating it (ignores any addOutput(), etc calls made before this)
void	runTest() Runs the test and validates the results
void	setKeyGroupingComparator(org.apache.hadoop.io.RawComparator<K2> groupingComparator) Set the key grouping comparator, similar to calling the following API calls but passing a real instance rather than just the class: pre 0.20.1 API: JobConf#setOutputValueGroupingComparator(Class) 0.20.1+ API: Job.setGroupingComparatorClass(Class)
void	setKeyOrderComparator(org.apache.hadoop.io.RawComparator<K2> orderComparator) Set the key value order comparator, similar to calling the following API calls but passing a real instance rather than just the class: pre 0.20.1 API: JobConf#setOutputKeyComparatorClass(Class) 0.20.1+ API: Job.setSortComparatorClass(Class)
List<Pair<K2,List<V2>>>	shuffle(List<Pair<K2,V2>> mapOutputs) Take the outputs from the Mapper, combine all values for the same key, and sort them by key.

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

formatValueList, getConfiguration, getExpectedOutputs, parseCommaDelimitedList, parseTabbedPair, resetOutput, setConfiguration, validate

Methods inherited from class java.lang.Object

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

Field Detail

LOG

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

inputList

protected List<Pair<K1,V1>> inputList

keyGroupComparator

protected Comparator<K2 extends Comparable> keyGroupComparator

Key group comparator

keyValueOrderComparator

protected Comparator<K2 extends Comparable> keyValueOrderComparator

Key value order comparator

Constructor Detail

MapReduceDriverBase

public MapReduceDriverBase()

Method Detail

addInput

public void addInput(K1 key,
                     V1 val)

Adds an input to send to the mapper

Parameters:

key -

val -

addInput

public void addInput(Pair<K1,V1> input)

Adds an input to send to the Mapper

Parameters:

input - The (k, v) pair to add to the input list.

addOutput

public void addOutput(Pair<K3,V3> outputRecord)

Adds an output (k, v) pair we expect from the Reducer

Parameters:

outputRecord - The (k, v) pair to add

addOutput

public void addOutput(K3 key,
                      V3 val)

Adds a (k, v) pair we expect as output from the Reducer

Parameters:

key -

val -

addInputFromString

public void addInputFromString(String input)

Expects an input of the form "key \t val" Forces the Mapper input types to Text.

Parameters:

input - A string of the form "key \t val". Trims any whitespace.

addOutputFromString

public void addOutputFromString(String output)

Expects an input of the form "key \t val" Forces the Reducer output types to Text.

Parameters:

output - A string of the form "key \t val". Trims any whitespace.

run

public abstract List<Pair<K3,V3>> 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 TestDriver<K1,V1,K3,V3>

Returns:

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

Throws:

IOException

runTest

public void runTest()
             throws RuntimeException

Description copied from class: TestDriver

Runs the test and validates the results

Specified by:

runTest in class TestDriver<K1,V1,K3,V3>

Throws:

RuntimeException - if they don't *

shuffle

public List<Pair<K2,List<V2>>> shuffle(List<Pair<K2,V2>> mapOutputs)

Take the outputs from the Mapper, combine all values for the same key, and sort them by key.

Parameters:

mapOutputs - An unordered list of (key, val) pairs from the mapper

Returns:

the sorted list of (key, list(val))'s to present to the reducer

setKeyGroupingComparator

public void setKeyGroupingComparator(org.apache.hadoop.io.RawComparator<K2> groupingComparator)

Set the key grouping comparator, similar to calling the following API calls but passing a real instance rather than just the class:

• pre 0.20.1 API: JobConf#setOutputValueGroupingComparator(Class)
• 0.20.1+ API: Job.setGroupingComparatorClass(Class)

Parameters:

groupingComparator -

setKeyOrderComparator

public void setKeyOrderComparator(org.apache.hadoop.io.RawComparator<K2> orderComparator)

Set the key value order comparator, similar to calling the following API calls but passing a real instance rather than just the class:

• pre 0.20.1 API: JobConf#setOutputKeyComparatorClass(Class)
• 0.20.1+ API: Job.setSortComparatorClass(Class)

Parameters:

orderComparator -