Connector, ConnectorView - base classes for connector subjects and views
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
- 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
- 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
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
- 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.
CGlue(3U), GraphicComp(3U), GraphicView(3U), Path(3U), StateVar(3U), edit(3U0,