Oracle® Fusion Middleware C++ API Reference for Oracle Coherence
12c (12.2.1.2.0)
E77779-01

ExtractorEventTransformer Class Reference

#include <coherence/util/transformer/ExtractorEventTransformer.hpp>

List of all members.

Detailed Description

ExtractorEventTransformer is a special purpose MapEventTransformer implementation that transforms emitted events, extracting one or more properties from either the OldValue or the NewValue.

This transformation will generally result in the change of the values' data type.

Example: the following code will register a listener to receive events only if the value of the AccountBalance property changes. The transformed event's NewValue will be a List containing the LastTransactionTime and AccountBalance properties. The OldValue will always be null. 

    Filter::View vFilter =
       ValueChangeEventFilter::create("getAccountBalance");
    ValueExtractor::View vExtractor =
       MultiExtractor::create(MultiExtractor::createExtractors(
           "getLastTransactionTime,getAccountBalance"));
    MapEventTransformer::Handle hTransformer =
       ExtractorEventTransformer::create(NULL, vExtractor);

    cache->addMapListener(listener,
       MapEventTransformerFilter::create(vFilter, hTransformer), false);

Author:
djl 2008.06.17

Public Types

typedef spec::Handle Handle
 ExtractorEventTransformer Handle definition.
typedef spec::View View
 ExtractorEventTransformer View definition.
typedef spec::Holder Holder
 ExtractorEventTransformer Holder definition.

Public Member Functions

virtual MapEvent::Handle transform (MapEvent::Handle hEvent) const
 
virtual void readExternal (PofReader::Handle hIn)
 
virtual void writeExternal (PofWriter::Handle hOut) const
 
virtual bool equals (Object::View v) const
 
virtual size32_t hashCode () const
 
virtual TypedHandle
< const String > 		toString () const
 
virtual
ValueExtractor::View 		getOldValueExtractor () const
 Return a ValueExtractor used to transfrom the event's OldValue.
virtual
ValueExtractor::View 		getNewValueExtractor () const
 Return a ValueExtractor used to transfrom the event's NewValue.

Protected Member Functions

 ExtractorEventTransformer ()
 Default constructor (necessary for the PortableObject interface).
 ExtractorEventTransformer (ValueExtractor::View vExtractor)
 Construct a ExtractorEventTransformer that transforms MapEvent values based on the specified extractor.
 ExtractorEventTransformer (ValueExtractor::View vExtractorOld, ValueExtractor::View vExtractorNew)
 Construct a ExtractorEventTransformer that transforms MapEvent values based on the specified extractors.

Constructor & Destructor Documentation

ExtractorEventTransformer ( ValueExtractor::View  vExtractor  )  [protected]

Construct a ExtractorEventTransformer that transforms MapEvent values based on the specified extractor.

Note: The specified extractor will be applied to both old and new values.

Parameters:
vExtractor ValueExtractor to extract MapEvent values

ExtractorEventTransformer ( ValueExtractor::View  vExtractorOld,
ValueExtractor::View  vExtractorNew 
) [protected]

Construct a ExtractorEventTransformer that transforms MapEvent values based on the specified extractors.

Passing null indicates that the corresponding values should be skipped completely.

Parameters:
vExtractorOld extractor to extract the OldValue property(s)
vExtractorNew extractor to extract the NewValue property(s)

Member Function Documentation

virtual ValueExtractor::View getOldValueExtractor (  )  const [virtual]

Return a ValueExtractor used to transfrom the event's OldValue.

Returns:
an extractor from the OldValue

virtual ValueExtractor::View getNewValueExtractor (  )  const [virtual]

Return a ValueExtractor used to transfrom the event's NewValue.

Returns:
an extractor from the NewValue

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