Oracle® Fusion Middleware C++ API Reference for Oracle Coherence: BetweenFilter Class Reference

Detailed Description

Filter

We use the standard ISO/IEC 9075:1992 semantic, according to which "X between Y and Z" is equivalent to "X >= Y && X <= Z". 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.

Author:

djl 2008.04.07

jk 2014.05.19

Public Types

typedef spec::Handle

Handle

BetweenFilter Handle definition.

typedef spec::View

View

BetweenFilter View definition.

typedef spec::Holder

Holder

BetweenFilter 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:

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

virtual TypedHandle
< const String >

toString () const

Output a human-readable description of this Object to the given stream.

Note that when overriding this method the return type must be TypedHandle<const String> rather then String::View. These two types are assignment compatible but not equivalent and declaring the override with String::View will not be a compatible override.

coherence::lang::operator<<(std::ostream, Object::View) is defined and will call into the toString 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 and is generally how toString() will be implemented.

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

 String::View vs = COH_TO_STRING(vKey << " = " << vValue);

The COH_TO_STRING macro is also the most common way to implement the toString method. For example:

 virtual TypedHandle<const String> Person::toString() const
     {
     return COH_TO_STRING("Name: " << f_sName << " SSN: " << f_nSSN);
     }

Returns:: a string representation of this object

virtual
ValueExtractor::View

getValueExtractor () const

Obtain the ValueExtractor used by this filter.

virtual Comparable::View

getLowerBound () const

Obtain the lower bound of the range used by this filter.

virtual Comparable::View

getUpperBound () const

Obtain the upper bound of the range used by this filter.

virtual bool

isLowerBoundInclusive () const

Obtain the flag indicating whether extracted values matching the lower bound of the range used by this filter will evaluate to true.

virtual bool

isUpperBoundInclusive () const

Obtain the flag indicating whether extracted values matching the upper bound of the range used by this filter will evaluate to true.

Protected Member Functions

BetweenFilter ()

Default constructor (necessary for the PortableObject interface).

BetweenFilter (ValueExtractor::View vExtractor, Comparable::View vFrom, Comparable::View vTo)

Construct a BetweenFilter for testing "Between" condition.

BetweenFilter (ValueExtractor::View vExtractor, Comparable::View vLowerBound, Comparable::View vUpperBound, bool fIncludeLowerBound, bool fIncludeUpperBound)

Construct a BetweenFilter for testing "Between" condition.

Constructor & Destructor Documentation

BetweenFilter	(	ValueExtractor::View	vExtractor,
		Comparable::View	vFrom,
		Comparable::View	vTo
	)			`[protected]`

Construct a BetweenFilter for testing "Between" condition.

Parameters:

	vExtractor	the ValueExtractor to use by this filter
	vFrom	the object to compare the "Greater or Equals" boundary with
	vTo	the object to compare the "Less or Equals" boundary with

BetweenFilter	(	ValueExtractor::View	vExtractor,
		Comparable::View	vLowerBound,
		Comparable::View	vUpperBound,
		bool	fIncludeLowerBound,
		bool	fIncludeUpperBound
	)			`[protected]`

Construct a BetweenFilter for testing "Between" condition.

Parameters:

	vExtractor	The ValueExtractor to be used by this filter
	vLowerBound	The lower bound of the range
	vUpperBound	The upper bound of the range
	fIncludeLowerBound	A flag indicating whether values matching the lower bound evaluate to true
	fIncludeUpperBound	A flag indicating whether values matching the upper bound evaluate to true

Member Function Documentation

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

Obtain the ValueExtractor used by this filter.

Returns:: the ValueExtractor::View used by this filter

virtual Comparable::View getLowerBound ( ) const [virtual]

Obtain the lower bound of the range used by this filter.

Returns:: the lower bound Object::View used by this filter

virtual Comparable::View getUpperBound ( ) const [virtual]

Obtain the upper bound of the range used by this filter.

Returns:: the upper bound Object::View used by this filter

virtual bool isLowerBoundInclusive ( ) const [virtual]

Obtain the flag indicating whether extracted values matching the lower bound of the range used by this filter will evaluate to true.

Returns:: the flag indicating whether extracted values matching the lower bound of the range used by this filter will evaluate to true.

virtual bool isUpperBoundInclusive ( ) const [virtual]

Obtain the flag indicating whether extracted values matching the upper bound of the range used by this filter will evaluate to true.

Returns:: the flag indicating whether extracted values matching the upper bound of the range used by this filter will evaluate to true.