Oracle® Fusion Middleware C++ API Reference for Oracle Coherence
DistinctValues Class Reference
List of all members.
Return the set of unique values extracted from a set of entries in a Map.
If the set of entries is empty, an empty set is returned.
This aggregator could be used in combination with coherence::util::extractor::MultiExtractor allowing to collect all unique combinations (tuples) of a given set of attributes.
The DistinctValues aggregator covers a simple case of a more generic aggregation pattern implemented by the GroupAggregator, which in addition to collecting all distinct values or tuples, runs an aggregation against each distinct entry set (group).
- djl 2008.05.12
typedef spec::Handle ||Handle|
| ||DistinctValues Handle definition. |
typedef spec::View ||View|
| ||DistinctValues View definition. |
typedef spec::Holder ||Holder|
| ||DistinctValues Holder definition. |
Protected Member Functions
| ||Default constructor (necessary for the PortableObject interface). |
| ||DistinctValues (ValueExtractor::View vExtractor)|
| ||Construct a DistinceValues aggregator. |
virtual void ||init (bool fFinal)|
| ||Initialize the aggregation result.|
|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.|
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.
|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.|
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.
|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|
- the result of the aggregation process
|virtual Set::Handle ||ensureSet ()|
| ||Return a set that can be used to store distinct values, creating it if one has not already been created. |
MemberHandle< Set > ||m_hSet|
| ||The resulting set of distinct values. |
Constructor & Destructor Documentation
Construct a DistinceValues aggregator.
|vExtractor ||the extractor that provides a value in the form of any object |
Member Function Documentation
Return a set that can be used to store distinct values, creating it if one has not already been created.
- a set that can be used to store distinct values
The documentation for this class was generated from the following file:
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