Oracle Coherence for C++ API
Release 3.7.0.0

E18684-01

ValueChangeEventFilter Class Reference

#include <coherence/util/filter/ValueChangeEventFilter.hpp>

Inherits ExtractorFilter.

List of all members.


Detailed Description

Filter which evaluates the content of a MapEvent values based on the specified value extractor.

This filter evaluates to true only for update events that change the value of an extracted attribute.

Example: a filter that evaluates to true if there is an update to an Employee object that changes a value of the LastName property.

   ValueChangeEventFilter::create(ReflectionExtractor::create("LastName"));
 

see MapEventFilter

Author:
djl 2008.05.19

Public Types

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

Public Member Functions

virtual bool evaluate (Object::View v) const
 Apply the test to the object.

Parameters:
v the object to test
Returns:
true if the test passes, false otherwise

virtual bool equals (Object::View v) const
 
virtual size32_t hashCode () const
 Return a hash code value for the Object.

This method is supported for the benefit of hash-based containers.

The general contract of hashCode is:

  • Whenever it is invoked on the same Object more than once during an execution of an application, the hashCode method must consistently return the same value, provided no information used in equals comparisons on the object is modified. This value need not remain consistent from one execution of an application to another execution of the same application.
  • If two Objects are equal according to the equals method, then calling the hashCode method on each of the two Objects must produce the same value.
  • It is not required that if two Objects are unequal according to the equals method, then calling the hashCode method on each of the two objects must produce distinct results. However, the programmer should be aware that producing distinct results for unequal objects may improve the performance of hash-based containers.

The default implementation is identity based.

Returns:
a hash code value for this Object

virtual void toStream (std::ostream &out) const
 Output a human-readable description of this Object to the given stream.

coherence::lang::operator<<(std::ostream, Object::View) is defined and will call into the toStream method, to output Objects. If a managed String object is desired, the COH_TO_STRING macro can be used to build up a String from streamable contents.

 Object::View vKey   = ...
 Object::View vValue = ...
 std::cout << vKey << " = " << vValue << std::endl;

 String::Handle hs = COH_TO_STRING(vKey << " = " << vValue);

Parameters:
out the stream used to output the description


Protected Member Functions

 ValueChangeEventFilter ()
 Default constructor (necessary for the PortableObject interface).
 ValueChangeEventFilter (ValueExtractor::View vValueExtractor)
 Construct a ValueChangeEventFilter that evaluates MapEvent values based on the specified extractor.
virtual bool evaluateExtracted (Object::View vExtracted) const
 Evaluate the specified extracted value.

Constructor & Destructor Documentation

ValueChangeEventFilter ( ValueExtractor::View  vValueExtractor  )  [protected]

Construct a ValueChangeEventFilter that evaluates MapEvent values based on the specified extractor.

Parameters:
vExtractor ValueExtractor to extract MapEvent values


Member Function Documentation

virtual bool evaluateExtracted ( Object::View  vExtracted  )  const [protected, virtual]

Evaluate the specified extracted value.

Parameters:
vExtracted an extracted value to evaluate

Implements ExtractorFilter.


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