org.apache.accumulo.examples.simple.combiner

Class StatsCombiner

java.lang.Object

org.apache.accumulo.core.iterators.WrappingIterator

org.apache.accumulo.core.iterators.Combiner

org.apache.accumulo.examples.simple.combiner.StatsCombiner

All Implemented Interfaces:

OptionDescriber, SortedKeyValueIterator<Key,Value>

public class StatsCombiner
extends Combiner

This combiner calculates the max, min, sum, and count of long integers represented as strings in values. It stores the result in a comma-separated value of the form min,max,sum,count. If such a value is encountered while combining, its information is incorporated into the running calculations of min, max, sum, and count. See Combiner for more information on which values are combined together. See docs/examples/README.combiner for instructions.

Nested Class Summary

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 and Description
static String	RADIX_OPTION

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

ALL_OPTION, COLUMNS_OPTION

Constructor Summary

Constructors

Constructor and Description
StatsCombiner()

Method Summary

Methods

Modifier and Type	Method and Description
OptionDescriber.IteratorOptions	describeOptions()
void	init(SortedKeyValueIterator<Key,Value> source, Map<String,String> options, IteratorEnvironment env)
Value	reduce(Key key, Iterator<Value> iter)
static void	setRadix(IteratorSetting iterConfig, int base) A convenience method for setting the expected base/radix of the numbers
boolean	validateOptions(Map<String,String> options)

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

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

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

Field Detail

RADIX_OPTION

public static final String RADIX_OPTION

See Also:

Constant Field Values

Constructor Detail

StatsCombiner

public StatsCombiner()

Method Detail

reduce

public Value reduce(Key key,
           Iterator<Value> iter)

Specified by:

reduce in class Combiner

init

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

Specified by:

init in interface SortedKeyValueIterator<Key,Value>

Overrides:

init in class Combiner

Throws:

IOException

describeOptions

public OptionDescriber.IteratorOptions describeOptions()

Specified by:

describeOptions in interface OptionDescriber

Overrides:

describeOptions in class Combiner

validateOptions

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

Specified by:

validateOptions in interface OptionDescriber

Overrides:

validateOptions in class Combiner

setRadix

public static void setRadix(IteratorSetting iterConfig,
            int base)

A convenience method for setting the expected base/radix of the numbers

Parameters:

iterConfig - Iterator settings to configure

base - The expected base/radix of the numbers.