NAME

       Connector, ConnectorView - base classes for connector subjects and views

SYNOPSIS

       #include <Unidraw/Components/connector.h>

DESCRIPTION

       Connector  is  an  abstract  base  class  for  graphical  component  subjects that enforce
       different  connectivity  semantics  depending  on  the  particular   connector   subclass.
       ConnectorView is the abstract base class for views of connector subjects.  A connector can
       be connected to one or more other connectors.  Once connected, two connectors  can  affect
       each other's position in specific ways as defined by the semantics of the connection.

       Connectors  also  participate in the propagation of state variable values during dataflow.
       Two connected connectors with bound state variables will assign the  value  of  one  state
       variable  to  other, and the direction of transfer depends on the connectors' transmission
       method.  For example, if the transmission method of connector C1 with bound state variable
       S1  is  In, and if the transmission method of connector C2 with bound state variable S2 is
       Out, and if C1 and C2 are connected, then S1 will be  assigned  the  value  of  S2  during
       dataflow.

CONNECTOR PUBLIC OPERATIONS

       virtual void Interpret(Command*)
       virtual void Uninterpret(Command*)
              In addition to (un)interpreting the commands GraphicComp (un)interprets, connectors
              also (un)interpret DeleteCmd and CutCmd to sever and  restore  any  connections  to
              them.

       virtual void Connect(Connector*, CGlue* = nil);
              Connect  this  connector  to  the  given  one,  optionally  with  a  piece of CGlue
              interposed.  This operation allows redundant connections by default.

       virtual void Disconnect(Connector*)
       void DisconnectAll()
              Disconnect the given connector from this one, if they are connected.  DisconnectAll
              calls Disconnect on all connected connectors until no connections remain.

       virtual boolean ConnectedTo(Connector*)
              Return whether this connector is connected to the given one.

       virtual void GetCenter(float&, float&)
              Return the coordinates of the connector's center, which defines its position.

       virtual void SetBinding(StateVar*)
       virtual StateVar* GetBinding()
              Assign  and  return  the  state  variable bound to the connector, if any.  Only one
              state variable can be bound to a connector at a time.

       virtual void SetTransMethod(TransMethod)
       virtual TransMethod GetTransMethod()
              Assign and return the connector's transmission method.

       virtual void Transmit(Path* = nil)
              Initiate dataflow originating from this connector, optionally based on  information
              supplied  in the given path object.  Other Unidraw or application objects call this
              operation whenever data modifications should be propagated.

CONNECTOR PROTECTED OPERATIONS

       Connector(Graphic* = nil)
              Initialize the connector instance, optionally with a graphic whose  center  defines
              the connector's position.

       virtual void ConnectMe(Connector*)
       virtual void DisconnectMe(Connector*)
              Connectors  maintain  a  list  of  the connectors to which they are connected.  The
              Connect and Disconnect operations update this connector's list, while the ConnectMe
              and DisconnectMe operations inform their argument to update their lists.

       void Retransmit(Path*)
       void Retransmit(Connector* peer, Path*)
       boolean Transferable(Connector* peer)
              The  Transmit  operation  uses these operations to propagate state variable values.
              The first Retransmit function calls the second one on each of the connector's peers
              (i.e.,  the  connectors  to  which  it  is connected) if the path records that this
              connector has not already been visited (otherwise propagation ceases).   The  first
              Retransmit  copies  the  path  if necessary to avoid accumulating visit information
              from multiple branches.  The second Retransmit calls  Transferable,  which  returns
              whether  the  value  of  this  connector's state variable can be transferred to the
              given peer's state variable based on the two connectors' transmission methods.   If
              the  values  are  transferable,  then  the  Transferable  operation carries out the
              assignment to the peer's state variable as a side-effect.   The  second  Retransmit
              also  enables further propagation by evaluating the transfer function of the peer's
              parent and by calling the first Retransmit operation on the peer.

CONNECTORVIEW PUBLIC OPERATIONS

       Connector* GetConnector()
              Return the view's subject, if any.

CONNECTORVIEW PROTECTED OPERATIONS

       ConnectorView(Connector* = nil)
              The constructor takes a subject as an optional  argument.   The  view  will  attach
              itself to the subject if one is specified.

SEE ALSO

       CGlue(3U), GraphicComp(3U), GraphicView(3U), Path(3U), StateVar(3U), edit(3U0, globals(3U)