Oracle Coherence for C++ API
Release 3.7.1.0

E22845-01

XorFilter Class Reference

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

Inherits ArrayFilter.

List of all members.


Detailed Description

Filter which returns the logical exclusive or ("xor") of two other filters.

Author:
djl 2008.04.14
 

Public Types

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

Public Member Functions

virtual bool evaluateEntry (Map::Entry::View vEntry) const
 Apply the test to a Map::Entry.

Parameters:
 vEntry the Map::Entry to evaluate; never NULL
Returns:
true if the test passes, false otherwise
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 size32_t calculateEffectiveness (Map::View vMapIndexes, Set::View vSetKeys) const
 Given a Map of available indexes, determine if this IndexAwareFilter can use any of the indexes to assist in its processing, and if so, determine how effective the use of that index would be.

The returned value is an effectiveness estimate of how well this filter can use the specified indexes to filter the specified keys. An operation that requires no more than a single access to the index content (i.e. Equals, NotEquals) has an effectiveness of one. Evaluation of a single entry is assumed to have an effectiveness that depends on the index implementation and is usually measured as a constant number of the single operations. This number is referred to as evaluation cost.

If the effectiveness of a filter evaluates to a number larger than the keySet.size() * <evaluation cost> then a user could avoid using the index and iterate through the keySet calling evaluate rather then applyIndex.

Parameters:
 vMapIndexes the available MapIndex objects keyed by the related ValueExtractor; read-only
 vSetKeys the set of keys that will be filtered; read-only
Returns:
an effectiveness estimate of how well this filter can use the specified indexes to filter the specified keys
virtual Filter::View applyIndex (Map::View vMapIndexes, Set::Handle hSetKeys) const
 Filter remaining keys using a Map of available indexes.

The filter is responsible for removing all keys from the passed set of keys that the applicable indexes can prove should be filtered. If the filter does not fully evaluate the remaining keys using just the index information, it must return a filter (which may be an EntryFilter) that can complete the task using an iterating implementation. If, on the other hand, the filter does fully evaluate the remaining keys using just the index information, then it should return NULL to indicate that no further filtering is necessary.

Parameters:
 vMapIndexes the available MapIndex objects keyed by the related ValueExtractor; read-only
 hSetKeys the mutable set of keys that remain to be filtered
Returns:
a Filter object (which may be an EntryFilter) that can be used to process the remaining keys, or NULL if no additional filter processing is necessary

Protected Member Functions

 XorFilter ()
 Default constructor (necessary for the PortableObject interface).
 XorFilter (Filter::View vFilterLeft, Filter::View vFilterRight)
 Construct an XorFilter.

Constructor & Destructor Documentation

XorFilter ( Filter::View  vFilterLeft,
    Filter::View  vFilterRight 
  )    [protected]

Construct an XorFilter.

The result is defined as: vFilterLeft ^ vFilterRight

Parameters:
 vFilterLeft the "left" filter
 vFilterRight the "right" filter


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