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

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

Direct Known Subclasses:

ReduceDriver, ReduceDriver

public abstract class ReduceDriverBase<K1,V1,K2,V2>
extends TestDriver<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. 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.

Nested Class Summary

protected static class

ReduceDriverBase.ValueClassInstanceReuseList<T>

Field Summary

protected K1

inputKey

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

configuration, counterWrapper, expectedEnumCounters, expectedOutputs, expectedStringCounters, LOG

Constructor Summary

ReduceDriverBase()

Method Summary

void	addInputValue(V1 val) adds an input value to send to the reducer
void	addInputValues(List<V1> values) Adds a set of input values to send to the reducer
void	addOutput(K2 key, V2 val) Adds an output (k, v) pair we expect from the Reducer
void	addOutput(Pair<K2,V2> outputRecord) Adds an output (k, v) pair we expect from the Reducer
void	addOutputFromString(String output) Deprecated. No replacement due to lack of type safety and incompatibility with non Text Writables
List<V1>	getInputValues() Returns a list which when iterated over, returns the same instance of the value each time with different contents similar to how Hadoop currently works with Writables.
abstract 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	runTest(boolean orderMatters) Runs the test and validates the results
void	setInput(K1 key, List<V1> values) Sets the input to send to the reducer
void	setInputFromString(String input) Deprecated. No replacement due to lack of type safety and incompatibility with non Text Writables
void	setInputKey(K1 key) Sets the input key to send to the Reducer
void	setInputValues(List<V1> values) Sets the input values to send to the reducer; overwrites existing ones

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

formatValueList, getConfiguration, getExpectedEnumCounters, getExpectedOutputs, getExpectedStringCounters, parseCommaDelimitedList, parseTabbedPair, resetExpectedCounters, resetOutput, runTest, setConfiguration, validate, validate, withCounter, withCounter

Methods inherited from class java.lang.Object

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

Field Detail

inputKey

protected K1 inputKey

Constructor Detail

ReduceDriverBase

public ReduceDriverBase()

Method Detail

getInputValues

public List<V1> getInputValues()

Returns a list which when iterated over, returns the same instance of the value each time with different contents similar to how Hadoop currently works with Writables.

Returns:

List of values

setInputKey

public void setInputKey(K1 key)

Sets the input key to send to the Reducer

addInputValue

public void addInputValue(V1 val)

adds an input value to send to the reducer

Parameters:

val -

setInputValues

public void setInputValues(List<V1> values)

Sets the input values to send to the reducer; overwrites existing ones

Parameters:

values -

addInputValues

public void addInputValues(List<V1> values)

Adds a set of input values to send to the reducer

Parameters:

values -

setInput

public void setInput(K1 key,
                     List<V1> values)

Sets the input to send to the reducer

Parameters:

key -

values -

addOutput

public void addOutput(Pair<K2,V2> outputRecord)

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

Parameters:

outputRecord - The (k, v) pair to add

addOutput

public void addOutput(K2 key,
                      V2 val)

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

Parameters:

key - The key part of a (k, v) pair to add

val - The val part of a (k, v) pair to add

setInputFromString

@Deprecated
public void setInputFromString(String input)

Deprecated. No replacement due to lack of type safety and incompatibility with non Text Writables

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

Parameters:

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

addOutputFromString

@Deprecated
public void addOutputFromString(String output)

Deprecated. No replacement due to lack of type safety and incompatibility with non Text Writables

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<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 TestDriver<K1,V1,K2,V2>

Returns:

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

Throws:

IOException

runTest

public void runTest(boolean orderMatters)

Description copied from class: TestDriver

Runs the test and validates the results

Specified by:

runTest in class TestDriver<K1,V1,K2,V2>

Parameters:

orderMatters - Whether or not output ordering is important