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com.tangosol.util.aggregator
Class DoubleAverage

java.lang.Object
com.tangosol.util.Base
com.tangosol.util.BitHelper
com.tangosol.util.ExternalizableHelper
com.tangosol.util.aggregator.AbstractAggregator
com.tangosol.util.aggregator.AbstractDoubleAggregator
com.tangosol.util.aggregator.DoubleAverage

All Implemented Interfaces:

ExternalizableLite, PortableObject, InvocableMap.EntryAggregator, InvocableMap.ParallelAwareAggregator, java.io.Serializable

public class DoubleAverage

extends AbstractDoubleAggregator

Calculates an average for values of any numeric type extracted from a set of entries in a Map. All the extracted Number objects will be treated as Java double values. If the set of entries is empty, a null result is returned.

Since:

Coherence 3.1

Author:

gg 2005.09.05

Nested Class Summary

Nested classes/interfaces inherited from interface com.tangosol.util.InvocableMap.ParallelAwareAggregator

InvocableMap.ParallelAwareAggregator.PartialResultAggregator

Field Summary

Fields inherited from class com.tangosol.util.aggregator.AbstractDoubleAggregator

m_count, m_dflResult

Fields inherited from class com.tangosol.util.aggregator.AbstractAggregator

m_fParallel

Constructor Summary

DoubleAverage()
Default constructor (necessary for the ExternalizableLite interface).

DoubleAverage(java.lang.String sMethod)
Construct an DoubleAverage object.

DoubleAverage(ValueExtractor extractor)
Construct a DoubleAverage aggregator.

Method Summary

protected java.lang.Object	finalizeResult(boolean fFinal) Obtain the result of the aggregation.
protected void	init(boolean fFinal) Initialize the aggregation result.
protected void	process(java.lang.Object o, boolean fFinal) Incorporate one aggregatable value into the result.

Methods inherited from class com.tangosol.util.aggregator.AbstractAggregator

aggregate, aggregateResults, equals, getParallelAggregator, getValueExtractor, hashCode, processEntry, readExternal, readExternal, toString, writeExternal, writeExternal

Methods inherited from class com.tangosol.util.BitHelper

countBits, countBits, countBits, indexOfLSB, indexOfLSB, indexOfLSB, indexOfMSB, indexOfMSB, indexOfMSB, rotateLeft, rotateLeft, rotateLeft, rotateRight, rotateRight, rotateRight, toBitString, toBitString, toBitString, toBytes, toBytes, toBytes, toBytes, toInt, toInt, toLong, toLong

Constructor Detail

DoubleAverage

public DoubleAverage()

Default constructor (necessary for the ExternalizableLite interface).

DoubleAverage

public DoubleAverage(ValueExtractor extractor)

Construct a DoubleAverage aggregator.

Parameters:

extractor - the extractor that provides a value in the form of any Java object that is a Number

DoubleAverage

public DoubleAverage(java.lang.String sMethod)

Construct an DoubleAverage object.

Parameters:

sMethod - the name of the method that returns a value in the form of any Java object that is a Number

Method Detail

init

protected void init(boolean fFinal)

Initialize the aggregation result.

Overrides:

init in class AbstractDoubleAggregator

Parameters:

fFinal - true is passed if the aggregation process that is being initialized must produce a final aggregation result; this will only be false if a parallel approach is being used and the initial (partial) aggregation process is being initialized

process

protected void process(java.lang.Object o,
                       boolean fFinal)

Incorporate one aggregatable value into the result.

If the fFinal parameter is true, the given object is a partial result (returned by an individual parallel aggregator) that should be incorporated into the final result; otherwise, the object is a value extracted from an InvocableMap.Entry.

Specified by:

process in class AbstractAggregator

Parameters:

o - the value to incorporate into the aggregated result

fFinal - true to indicate that the given object is a partial result returned by a parallel aggregator

finalizeResult

protected java.lang.Object finalizeResult(boolean fFinal)

Obtain the result of the aggregation.

If the fFinal parameter is true, the returned object must be the final result of the aggregation; otherwise, the returned object will be treated as a partial result that should be incorporated into the final result.

Overrides:

finalizeResult in class AbstractDoubleAggregator

Parameters:

fFinal - true to indicate that the final result of the aggregation process should be returned; this will only be false if a parallel approach is being used

Returns:

the result of the aggregation process

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