Class TopNAggregator

TopNAggregator is a ParallelAwareAggregator that aggregates the top N extracted values into an array. The extracted values must not be null, but do not need to be unique.

Inheritance

object

TopNAggregator

Implements

IParallelAwareAggregator

IEntryAggregator

IPartialResultAggregator

IPortableObject

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: Tangosol.Util.Aggregator

Assembly: Coherence.dll

Syntax

public class TopNAggregator : IParallelAwareAggregator, IEntryAggregator, IPartialResultAggregator, IPortableObject

Constructors

TopNAggregator()

Default constructor.

Declaration

public TopNAggregator()

TopNAggregator(IValueExtractor, IComparer, int)

Construct a TopNAggregator that will aggregate the top extracted values, as determined by the specified comparator.

Declaration

public TopNAggregator(IValueExtractor extractor, IComparer comparer, int cResults)

Parameters

Type	Name	Description
IValueExtractor	extractor	The extractor.
IComparer	comparer	The comparer for extracted values.
int	cResults	The maximum number of results to return.

Properties

Comparer

The IComparer used by this aggregator.

Declaration

protected IComparer Comparer { get; set; }

Property Value

Type	Description
IComparer

Extractor

The ValueExtractor used by this aggregator.

Declaration

protected IValueExtractor Extractor { get; set; }

Property Value

Type	Description
IValueExtractor

IsParallel

True iff this aggregator is to be used in parallel.

Declaration

protected bool IsParallel { get; set; }

Property Value

Type	Description
bool

ParallelAggregator

Get an aggregator that can take the place of this aggregator in situations in which the IInvocableCache can aggregate in parallel.

Declaration

public virtual IEntryAggregator ParallelAggregator { get; }

Property Value

Type	Description
IEntryAggregator	The aggregator that will be run in parallel.

Results

The maximum number of results to include in the aggregation result.

Declaration

protected int Results { get; set; }

Property Value

Type	Description
int

Methods

AddToResult(ICollection, PartialResult)

Add the specified values to the result if they are within the top-N.

Declaration

protected void AddToResult(ICollection values, TopNAggregator.PartialResult result)

Parameters

Type	Name	Description
ICollection	values	The collection of values to add.
TopNAggregator.PartialResult	result	The result.

Aggregate(ICollection)

Process a set of IInvocableCacheEntry objects in order to produce an aggregated result.

Declaration

public virtual object Aggregate(ICollection entries)

Parameters

Type	Name	Description
ICollection	entries	A collection of read-only IInvocableCacheEntry objects to aggregate.

Returns

Type	Description
object	The aggregated result from processing the entries.

AggregatePartialResults(ICollection)

Aggregate the results of the parallel aggregations, producing a partial result logically representing the partial aggregation. The returned partial result will be further {@link ParallelAwareAggregator#aggregateResults aggregated} to produce the final result.

Declaration

public virtual object AggregatePartialResults(ICollection colPartialResults)

Parameters

Type	Name	Description
ICollection	colPartialResults	The partial results to agregate.

Returns

Type	Description
object	An aggregattion of the collection of partial results.

AggregateResults(ICollection)

Aggregate the results of the parallel aggregations.

Declaration

public virtual object AggregateResults(ICollection results)

Parameters

Type	Name	Description
ICollection	results	Results to aggregate.

Returns

Type	Description
object	The aggregation of the parallel aggregation results.

FinalizeResult(PartialResult)

Finalize the partial aggregation result.

Declaration

protected object[] FinalizeResult(TopNAggregator.PartialResult result)

Parameters

Type	Name	Description
TopNAggregator.PartialResult	result	The final aggregation result.

Returns

Type	Description
object[]	The finalized partial aggregation result.

ReadExternal(IPofReader)

Restore the contents of a user type instance by reading its state using the specified IPofReader object.

Declaration

public virtual void ReadExternal(IPofReader reader)

Parameters

Type	Name	Description
IPofReader	reader	The IPofReader from which to read the object's state.

Exceptions

Type	Condition
IOException	If an I/O error occurs.

WriteExternal(IPofWriter)

Save the contents of a POF user type instance by writing its state using the specified IPofWriter object.

Declaration

public virtual void WriteExternal(IPofWriter writer)

Parameters

Type	Name	Description
IPofWriter	writer	The IPofWriter to which to write the object's state.

Exceptions

Type	Condition
IOException	If an I/O error occurs.

Implements

IParallelAwareAggregator

IEntryAggregator

IPartialResultAggregator

IPortableObject