C++ API Reference for Oracle® Coherence Community Edition
(14.1.1.0.1)
F23533-01

ReducerAggregator Class Reference

#include <coherence/util/aggregator/ReducerAggregator.hpp>

Inherits AbstractAggregator.

List of all members.

---

Detailed Description

The ReducerAggregator is used to implement functionality similar to CacheMap::getAll(Collection) API.

Instead of returning the complete set of values, it will return a portion of value attributes based on the provided ValueExtractor.

This aggregator could be used in combination with coherence.util.extractor.MultiExtractor allowing one to collect tuples that are a subset of the attributes of each object stored in the cache.

Author:

par 04.25.13

Public Types
typedef spec::Handle	Handle
	ReducerAggregator Handle definition.
typedef spec::View	View
	ReducerAggregator View definition.
typedef spec::Holder	Holder
	ReducerAggregator Holder definition.
Protected Member Functions
	ReducerAggregator ()
	Default constructor.
	ReducerAggregator (ValueExtractor::View vExtractor)
	Construct a ReducerAggregator based on the specified extractor.
	ReducerAggregator (String::View vsMethod)
	Construct a ReducerAggregator based on the specified method name.
virtual void	init (bool fFinal)
	Initialize the aggregation result. This implementation throws an UnsupportedOperationException. 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
virtual void	process (Object::View vO, bool 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 coherence::util::InvocableMap::Entry. This implementation throws an UnsupportedOperationException. Parameters: vO  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
virtual Object::Holder	finalizeResult (bool 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. This implementation throws an UnsupportedOperationException. 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
virtual Map::Handle	ensureMap ()
	Return a map that can be used to store reduced values, creating it if one has not already been created.

---

Constructor & Destructor Documentation

ReducerAggregator

(

ValueExtractor::View

vExtractor

)

[protected]

Construct a ReducerAggregator based on the specified extractor.

Parameters:

vExtractor

the extractor that is used to extract the portion of the cached value

ReducerAggregator

(

String::View

vsMethod

)

[protected]

Construct a ReducerAggregator based on the specified method name.

Parameters:

vsMethod

the name of the method that is used to extract the portion of the cached value

---

Member Function Documentation

virtual Map::Handle ensureMap

(

)

[protected, virtual]

Return a map that can be used to store reduced values, creating it if one has not already been created.

Returns:

a set that can be used to store distinct values

---

The documentation for this class was generated from the following file:

• coherence/util/aggregator/ReducerAggregator.hpp

Copyright © 2000, 2020, Oracle and/or its affiliates. Licensed under the Universal Permissive License v 1.0 as shown at http://oss.oracle.com/licenses/upl.