Class SummingArrayCombiner
- java.lang.Object
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- org.apache.accumulo.core.iterators.WrappingIterator
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- org.apache.accumulo.core.iterators.Combiner
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- org.apache.accumulo.core.iterators.TypedValueCombiner<List<Long>>
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- org.apache.accumulo.core.iterators.user.SummingArrayCombiner
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- 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.
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Nested Class Summary
Nested Classes Modifier and Type Class Description static class
SummingArrayCombiner.DOSArrayEncoder<V>
static class
SummingArrayCombiner.FixedLongArrayEncoder
static class
SummingArrayCombiner.StringArrayEncoder
static class
SummingArrayCombiner.Type
static class
SummingArrayCombiner.VarLongArrayEncoder
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Nested classes/interfaces inherited from class org.apache.accumulo.core.iterators.Combiner
Combiner.ValueIterator
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Nested classes/interfaces inherited from interface org.apache.accumulo.core.iterators.OptionDescriber
OptionDescriber.IteratorOptions
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Field Summary
Fields Modifier and Type Field Description static Encoder<List<Long>>
FIXED_LONG_ARRAY_ENCODER
static Encoder<List<Long>>
STRING_ARRAY_ENCODER
static Encoder<List<Long>>
VAR_LONG_ARRAY_ENCODER
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Fields inherited from class org.apache.accumulo.core.iterators.TypedValueCombiner
LOSSY
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Fields inherited from class org.apache.accumulo.core.iterators.Combiner
ALL_OPTION, COLUMNS_OPTION, REDUCE_ON_FULL_COMPACTION_ONLY_OPTION
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Constructor Summary
Constructors Constructor Description SummingArrayCombiner()
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods 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
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Methods inherited from class org.apache.accumulo.core.iterators.Combiner
getTopKey, getTopValue, hasTop, next, seek, setColumns, setCombineAllColumns, setReduceOnFullCompactionOnly
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Methods inherited from class org.apache.accumulo.core.iterators.WrappingIterator
getSource, setSource
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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Methods inherited from interface org.apache.accumulo.core.iterators.YieldingKeyValueIterator
enableYielding
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Method Detail
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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 classTypedValueCombiner<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.
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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 interfaceSortedKeyValueIterator<Key,Value>
- Overrides:
init
in classTypedValueCombiner<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.- Throws:
IOException
- unused.
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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 interfaceOptionDescriber
- Overrides:
describeOptions
in classTypedValueCombiner<List<Long>>
- Returns:
- an iterator options object
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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 interfaceOptionDescriber
- Overrides:
validateOptions
in classTypedValueCombiner<List<Long>>
- Parameters:
options
- a map of option names to option values- Returns:
- true if options are valid, false otherwise (IllegalArgumentException preferred)
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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.
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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.
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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.
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