Network Router User Manual

210 GINA V4.0 System Administrator Guide – September 2000
Glossary
service
A →server provides services. Services are generally provided in rpc-like interfaces in
an API. Services are thus called. T-ORB provides an object-oriented API. Functions,
class methods and instance methods can be called remotely (with transaction
monitoring). →Stubs relieve the application of the task of dealing with communication
details.
shadowed attribute
A shadowed attribute is an attribute inherited from a base class ( Base :: attr ) that
redefines ( Derived :: attr ) the inheriting class (class Derived : public Base ). In
C++, this type of attribute can be addressed in the name scope of the base class
( Base :: attr ) as well as in that of the derived class ( Derived :: attr ).
signature
The signature of an operation consists of the type list of parameters used in the
operation.
skeleton
In CORBA terminology, a skeleton is the same as the →external interface under GINA.
smart pointer
The term smart pointer is used in C++ to refer to classes which overload the derefer-
encing operators * and ->. Smart pointers are often used to access →persistent
objects (see Persistency Service), or to access remote objects (see T-ORB).
stub
A stub shields the client application from the details of a →remote call. A stub method
or stub function can be called in the same way as a local method. The parameters are
encoded, the remote call is actually made and the results are decoded, if necessary,
within the stub method or stub function.
A representative object is needed for calling methods. We call this a stub object or a
proxy. In DCE, we talk about a client stub, rather than a stub.
synchronous request/call
In the case of the T-ORB procedure synchronous call, a client waits for the result of a
synchronous request/call, thereby blocking further operations. A normal C++ function
or method call is a synchronous call.
Furthermore, T-ORB allows clients to make a number of synchronous, remote requests
in parallel. The client waits until the results of all the calls have been received.