Inherits ComparisonFilter, and IndexAwareFilter.
List of all members.
In a case when either result of a method invocation or a value to compare are equal to NULL, the
evaluate test yields
false. This approach is equivalent to the way the NULL values are handled by SQL.
|LessFilter Handle definition. |
|LessFilter View definition. |
|LessFilter Holder definition. |
Public Member Functions
|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
|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.
Protected Member Functions
|Default constructor (necessary for the PortableObject interface). |
|LessFilter (ValueExtractor::View vValueExtractor, Comparable::View vComparable)|
|Construct a LessFilter for testing "Less" condition. |
|virtual bool||evaluateExtracted (Object::View vExtracted) const|
|Evaluate the specified extracted value.|