NAME¶
TransferFunct - transfer function base class
SYNOPSIS¶
#include <Unidraw/transfn.h>
DESCRIPTION¶
A transfer function defines relationships between state variables. A component
uses a transfer function to enforce dependencies between its state variables
during dataflow. State variables whose values change as a result of data
flowing into the component can thus affect the component's dependent state
variables as defined by its transfer function. A transfer function can define
dependencies between any number of state variables, but a component can define
only one transfer function.
PUBLIC OPERATIONS¶
- virtual void Evaluate(Path* = nil)
- Enforce the transfer function's dependencies between its
state variables, optionally depending on the information in a path. This
operation does nothing by default.
- virtual TransferFunct* Copy()
- Return a copy of the transfer function. Subclasses redefine
this operation to return an instance of their type.
- virtual void Read(istream&)
- virtual void Write(ostream&)
- Read and write the transfer function's contents to a stream
to support catalog operations. Read and write typically call first the
corresponding operations defined by their parent class, and then they read
or write their class-specific state.
- virtual ClassId GetClassId()
- virtual boolean IsA(ClassId)
- GetClassId returns the unique class identifier for the
TransferFunct subclass, while IsA returns whether the instance is of a
class or subclass corresponding to the given identifier. IsA typically
checks the given identifier against the instance's own (as defined by its
GetClassId operation) and, failing that, calls its parent classes' IsA
operation. All subclasses must redefine GetClassId and IsA to ensure that
their identifiers are unique and that instances are written and read
properly.
PROTECTED OPERATIONS¶
- TransferFunct()
- The constructor is protected to prevent instantiation.
- virtual Connector* GetBinding(StateVar*)
- Return the connector to which a state variable is
bound.
SEE ALSO¶
Catalog(3U), Component(3U), Connector(3U), Creator(3U), Path(3U), StateVar(3U)
classes(3U), istream(3C++), ostream(3C++)