Package org.apache.accumulo.core.iterators.user

Class SummingArrayCombiner

java.lang.Object

org.apache.accumulo.core.iterators.WrappingIterator

org.apache.accumulo.core.iterators.Combiner

org.apache.accumulo.core.iterators.TypedValueCombiner<List<Long>>

org.apache.accumulo.core.iterators.user.SummingArrayCombiner

All Implemented Interfaces:

OptionDescriber, SortedKeyValueIterator<Key,Value>, YieldingKeyValueIterator<Key,Value>

public class SummingArrayCombiner
extends TypedValueCombiner<List<Long>>

A Combiner that interprets Values as arrays of Longs and returns an array of element-wise sums.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	SummingArrayCombiner.DOSArrayEncoder<V>
static class	SummingArrayCombiner.FixedLongArrayEncoder
static class	SummingArrayCombiner.StringArrayEncoder
static enum	SummingArrayCombiner.Type
static class	SummingArrayCombiner.VarLongArrayEncoder

Nested classes/interfaces inherited from class org.apache.accumulo.core.iterators.Combiner

Combiner.ValueIterator

Nested classes/interfaces inherited from interface org.apache.accumulo.core.iterators.OptionDescriber

OptionDescriber.IteratorOptions

Field Summary

Fields

Modifier and Type	Field	Description
static final Encoder<List<Long>>	FIXED_LONG_ARRAY_ENCODER
static final Encoder<List<Long>>	STRING_ARRAY_ENCODER
static final Encoder<List<Long>>	VAR_LONG_ARRAY_ENCODER

Fields inherited from class org.apache.accumulo.core.iterators.TypedValueCombiner

LOSSY

Fields inherited from class org.apache.accumulo.core.iterators.Combiner

ALL_OPTION, COLUMNS_OPTION, REDUCE_ON_FULL_COMPACTION_ONLY_OPTION

Constructor Summary

Constructors

Constructor	Description
SummingArrayCombiner()

Method Summary

Modifier and Type	Method	Description
static List<Long>	arrayAdd(List<Long> la, List<Long> lb)
OptionDescriber.IteratorOptions	describeOptions()	Gets an iterator options object that contains information needed to configure this iterator.
void	init(SortedKeyValueIterator<Key,Value> source, Map<String,String> options, IteratorEnvironment env)	Initializes the iterator.
static void	setEncodingType(IteratorSetting is, Class<? extends Encoder<List<Long>>> encoderClass)	A convenience method for setting the encoding type.
static void	setEncodingType(IteratorSetting is, String encoderClassName)	A convenience method for setting the encoding type.
static void	setEncodingType(IteratorSetting is, SummingArrayCombiner.Type type)	A convenience method for setting the encoding type.
List<Long>	typedReduce(Key key, Iterator<List<Long>> iter)	Reduces a list of V into a single V.
boolean	validateOptions(Map<String,String> options)	Check to see if an options map contains all options required by an iterator and that the option values are in the expected formats.

Methods inherited from class org.apache.accumulo.core.iterators.TypedValueCombiner

deepCopy, reduce, setEncoder, setEncoder, setLossyness, testEncoder, testEncoder

Methods inherited from class org.apache.accumulo.core.iterators.Combiner

getTopKey, getTopValue, hasTop, next, seek, setColumns, setCombineAllColumns, setReduceOnFullCompactionOnly

Methods inherited from class org.apache.accumulo.core.iterators.WrappingIterator

getSource, setSource

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.accumulo.core.iterators.YieldingKeyValueIterator

enableYielding

Field Details

FIXED_LONG_ARRAY_ENCODER

public static final Encoder<List<Long>> FIXED_LONG_ARRAY_ENCODER

VAR_LONG_ARRAY_ENCODER

public static final Encoder<List<Long>> VAR_LONG_ARRAY_ENCODER

STRING_ARRAY_ENCODER

public static final Encoder<List<Long>> STRING_ARRAY_ENCODER

Constructor Details

SummingArrayCombiner

public SummingArrayCombiner()

Method Details

typedReduce

public List<Long> typedReduce(Key key,
 Iterator<List<Long>> iter)

Description copied from class: TypedValueCombiner

Reduces a list of V into a single V.

Specified by:

typedReduce in class TypedValueCombiner<List<Long>>

Parameters:

key - The most recent version of the Key being reduced.

iter - An iterator over the V for different versions of the key.

Returns:

The combined V.

arrayAdd

public static List<Long> arrayAdd(List<Long> la,
 List<Long> lb)

init

public void init(SortedKeyValueIterator<Key,Value> source,
 Map<String,String> options,
 IteratorEnvironment env)
          throws IOException

Description copied from interface: SortedKeyValueIterator

Initializes the iterator. Data should not be read from the source in this method.

Specified by:

init in interface SortedKeyValueIterator<Key,Value>

Overrides:

init in class TypedValueCombiner<List<Long>>

Parameters:

source - SortedKeyValueIterator source to read data from.

options - Map map of string option names to option values.

env - IteratorEnvironment environment in which iterator is being run, provided by Accumulo itself and is expected to be non-null.

Throws:

IOException - unused.

describeOptions

public OptionDescriber.IteratorOptions describeOptions()

Description copied from interface: OptionDescriber

Gets an iterator options object that contains information needed to configure this iterator. This object will be used by the accumulo shell to prompt the user to input the appropriate information.

Specified by:

describeOptions in interface OptionDescriber

Overrides:

describeOptions in class TypedValueCombiner<List<Long>>

Returns:

an iterator options object

validateOptions

public boolean validateOptions(Map<String,String> options)

Description copied from interface: OptionDescriber

Check to see if an options map contains all options required by an iterator and that the option values are in the expected formats.

Specified by:

validateOptions in interface OptionDescriber

Overrides:

validateOptions in class TypedValueCombiner<List<Long>>

Parameters:

options - a map of option names to option values

Returns:

true if options are valid, false otherwise (IllegalArgumentException preferred)

setEncodingType

public static void setEncodingType(IteratorSetting is,
 SummingArrayCombiner.Type type)

A convenience method for setting the encoding type.

Parameters:

is - IteratorSetting object to configure.

type - SummingArrayCombiner.Type specifying the encoding type.

setEncodingType

public static void setEncodingType(IteratorSetting is,
 Class<? extends Encoder<List<Long>>> encoderClass)

A convenience method for setting the encoding type.

Parameters:

is - IteratorSetting object to configure.

encoderClass - Class<? extends Encoder<List<Long>>> specifying the encoding type.

setEncodingType

public static void setEncodingType(IteratorSetting is,
 String encoderClassName)

A convenience method for setting the encoding type.

Parameters:

is - IteratorSetting object to configure.

encoderClassName - name of a class specifying the encoding type.