Package uk.gov.gchq.gaffer.accumulostore.key.core.impl

Class CoreKeyGroupByCombiner

java.lang.Object

org.apache.accumulo.core.iterators.WrappingIterator

uk.gov.gchq.gaffer.accumulostore.key.core.impl.CoreKeyGroupByCombiner

All Implemented Interfaces:

org.apache.accumulo.core.iterators.OptionDescriber, org.apache.accumulo.core.iterators.SortedKeyValueIterator<org.apache.accumulo.core.data.Key,org.apache.accumulo.core.data.Value>, org.apache.accumulo.core.iterators.YieldingKeyValueIterator<org.apache.accumulo.core.data.Key,org.apache.accumulo.core.data.Value>

Direct Known Subclasses:

CoreKeyGroupByAggregatorIterator

public abstract class CoreKeyGroupByCombiner
extends org.apache.accumulo.core.iterators.WrappingIterator
implements org.apache.accumulo.core.iterators.OptionDescriber

A copy of Accumulo Combiner but combining values with identical rowKey and column family.

Users extending this class must specify a reduce() method.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	CoreKeyGroupByCombiner.KeyValueIterator	A Java Iterator that iterates over the properties for a given row Key and column family from a source SortedKeyValueIterator.

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

org.apache.accumulo.core.iterators.OptionDescriber.IteratorOptions

Constructor Summary

Constructors

Constructor	Description
CoreKeyGroupByCombiner()

Method Summary

Modifier and Type	Method	Description
org.apache.accumulo.core.iterators.SortedKeyValueIterator<org.apache.accumulo.core.data.Key,org.apache.accumulo.core.data.Value>	deepCopy(org.apache.accumulo.core.iterators.IteratorEnvironment env)
org.apache.accumulo.core.iterators.OptionDescriber.IteratorOptions	describeOptions()
org.apache.accumulo.core.data.Key	getTopKey()
org.apache.accumulo.core.data.Value	getTopValue()
boolean	hasTop()
void	init(org.apache.accumulo.core.iterators.SortedKeyValueIterator<org.apache.accumulo.core.data.Key,org.apache.accumulo.core.data.Value> source, Map<String,String> options, org.apache.accumulo.core.iterators.IteratorEnvironment env)
void	next()
abstract Properties	reduce(String group, org.apache.accumulo.core.data.Key key, Iterator<Properties> iter, Set<String> groupBy, ElementAggregator viewAggregator)	Reduces an iterator of Properties into a single Properties object.
void	seek(org.apache.accumulo.core.data.Range range, Collection<org.apache.accumulo.core.data.ByteSequence> columnFamilies, boolean inclusive)
boolean	validateOptions(Map<String,String> options)

Methods inherited from class java.lang.Object

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

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

enableYielding

Constructor Detail

CoreKeyGroupByCombiner

public CoreKeyGroupByCombiner()

Method Detail

getTopKey

public org.apache.accumulo.core.data.Key getTopKey()

Specified by:

getTopKey in interface org.apache.accumulo.core.iterators.SortedKeyValueIterator<org.apache.accumulo.core.data.Key,org.apache.accumulo.core.data.Value>

Overrides:

getTopKey in class org.apache.accumulo.core.iterators.WrappingIterator

getTopValue

public org.apache.accumulo.core.data.Value getTopValue()

Specified by:

getTopValue in interface org.apache.accumulo.core.iterators.SortedKeyValueIterator<org.apache.accumulo.core.data.Key,org.apache.accumulo.core.data.Value>

Overrides:

getTopValue in class org.apache.accumulo.core.iterators.WrappingIterator

hasTop

public boolean hasTop()

Specified by:

hasTop in interface org.apache.accumulo.core.iterators.SortedKeyValueIterator<org.apache.accumulo.core.data.Key,org.apache.accumulo.core.data.Value>

Overrides:

hasTop in class org.apache.accumulo.core.iterators.WrappingIterator

next

public void next()
          throws IOException

Specified by:

next in interface org.apache.accumulo.core.iterators.SortedKeyValueIterator<org.apache.accumulo.core.data.Key,org.apache.accumulo.core.data.Value>

Overrides:

next in class org.apache.accumulo.core.iterators.WrappingIterator

Throws:

IOException

seek

public void seek(org.apache.accumulo.core.data.Range range,
                 Collection<org.apache.accumulo.core.data.ByteSequence> columnFamilies,
                 boolean inclusive)
          throws IOException

Specified by:

seek in interface org.apache.accumulo.core.iterators.SortedKeyValueIterator<org.apache.accumulo.core.data.Key,org.apache.accumulo.core.data.Value>

Overrides:

seek in class org.apache.accumulo.core.iterators.WrappingIterator

Throws:

IOException

reduce

public abstract Properties reduce(String group,
                                  org.apache.accumulo.core.data.Key key,
                                  Iterator<Properties> iter,
                                  Set<String> groupBy,
                                  ElementAggregator viewAggregator)

Reduces an iterator of Properties into a single Properties object.

Parameters:

group - the schema group taken from the key

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

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

groupBy - the groupBy properties

viewAggregator - an optional view aggregator

Returns:

The combined Properties.

deepCopy

public org.apache.accumulo.core.iterators.SortedKeyValueIterator<org.apache.accumulo.core.data.Key,org.apache.accumulo.core.data.Value> deepCopy(org.apache.accumulo.core.iterators.IteratorEnvironment env)

Specified by:

deepCopy in interface org.apache.accumulo.core.iterators.SortedKeyValueIterator<org.apache.accumulo.core.data.Key,org.apache.accumulo.core.data.Value>

Overrides:

deepCopy in class org.apache.accumulo.core.iterators.WrappingIterator

init

public void init(org.apache.accumulo.core.iterators.SortedKeyValueIterator<org.apache.accumulo.core.data.Key,org.apache.accumulo.core.data.Value> source,
                 Map<String,String> options,
                 org.apache.accumulo.core.iterators.IteratorEnvironment env)
          throws IOException

Specified by:

init in interface org.apache.accumulo.core.iterators.SortedKeyValueIterator<org.apache.accumulo.core.data.Key,org.apache.accumulo.core.data.Value>

Overrides:

init in class org.apache.accumulo.core.iterators.WrappingIterator

Throws:

IOException

validateOptions

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

Specified by:

validateOptions in interface org.apache.accumulo.core.iterators.OptionDescriber

describeOptions

public org.apache.accumulo.core.iterators.OptionDescriber.IteratorOptions describeOptions()

Specified by:

describeOptions in interface org.apache.accumulo.core.iterators.OptionDescriber