net.sf.farrago.cwm.core
Interface CwmDataType
- All Superinterfaces:
- CwmClassifier, CwmElement, CwmModelElement, CwmNamespace, RefBaseObject, RefFeatured, RefObject
- All Known Subinterfaces:
- CwmEnumeration, CwmSqldistinctType, CwmSqlsimpleType, CwmTypeAlias, FemSqldistinguishedType
- All Known Implementing Classes:
- CwmDataType$Hib, CwmEnumeration$Hib, CwmSqldistinctType$Hib, CwmSqlsimpleType$Hib, CwmTypeAlias$Hib, FemSqldistinguishedType$Hib
public interface CwmDataType
- extends CwmClassifier
DataType object instance interface.
A data type is a type whose values have no identity (i.e., they are pure
values). Data types include primitive built-in types (such as integer and
string) as well as definable enumeration types.
In the metamodel, a DataType defines a special kind of Classifier in which
operations are all pure functions (i.e., they can return data values but
they cannot change data values, because they have no identity). For
example, an "add" operation on a number with another number as an argument
yields a third number as a result; the target and argument are unchanged.
A DataType is a special kind of Classifier whose instances are primitive
values, not objects. For example, integers and strings are usually treated
as primitive values. A primitive value does not have an identity, so two
occurrences of the same value cannot be differentiated. Usually, DataTypes
are used for specification of the type of an attribute or parameter.
Note: This type should not be subclassed,
implemented or directly instantiated by clients. It is generated from a
MOF metamodel and implemented by Enki or MDR.