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

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 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 Object::View

getValue () const

Get the object to compare the reflection result with.

Static Public Member Functions

static int32_t

calculateIteratorEffectiveness (int32_t cKeys)

Helper method to calculate effectiveness (or rather ineffectiveness) of a simple iteration against a key set that has to be performed due to an absence of corresponding index.

Protected Member Functions

ComparisonFilter ()

Default constructor (necessary for the ExternalizableLite interface).

ComparisonFilter (ValueExtractor::View vValueExtractor, Object::View vObject)

Construct a ComparisonFilter.

virtual int32_t

calculateMatchEffectiveness (Map::View vMapIndexes, Set::View vSetKeys) const

Helper method to calculate effectiveness for ComparisonFilters that need no more than a single index match in order to retrieve all necessary keys to perform the applyIndex() operation.

virtual int32_t

calculateRangeEffectiveness (Map::View vMapIndexes, Set::View vSetKeys) const

Helper method to calculate effectiveness for ComparisonFilters that need a range of values from an index in order to retrieve all necessary keys to perform the applyIndex() operation.

Protected Attributes

FinalView< Object >

f_vValue

The value to compare to.

Constructor & Destructor Documentation

ComparisonFilter	(	ValueExtractor::View	vValueExtractor,
		Object::View	vObject
	)			`[protected]`

Construct a ComparisonFilter.

Parameters:

	vExtractor	the ComparisonFilter to use by this filter
	vObject	the object to compare the result with

Member Function Documentation

virtual int32_t calculateMatchEffectiveness	(	Map::View	vMapIndexes,
		Set::View	vSetKeys
	)			const `[protected, virtual]`

Helper method to calculate effectiveness for ComparisonFilters that need no more than a single index match in order to retrieve all necessary keys to perform the applyIndex() operation.

Such filters are: Contains, Equals, NotEquals.

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 int32_t calculateRangeEffectiveness	(	Map::View	vMapIndexes,
		Set::View	vSetKeys
	)			const `[protected, virtual]`

Helper method to calculate effectiveness for ComparisonFilters that need a range of values from an index in order to retrieve all necessary keys to perform the applyIndex() operation.

Such filters are: Less, LessEquals, Greater, GreaterEquals.

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

static int32_t calculateIteratorEffectiveness ( int32_t cKeys ) [static]

Helper method to calculate effectiveness (or rather ineffectiveness) of a simple iteration against a key set that has to be performed due to an absence of corresponding index.

Parameters:

cKeys

the number of keys to iterate through

virtual Object::View getValue ( ) const [virtual]

Get the object to compare the reflection result with.

Returns:: the object to compare the reflection result with