Abstract: Data structures, methods, and devices for facilitating servant invocation in a distributed client-server based object oriented operating system are disclosed. In one aspect of the invention, descriptor data structures, which contain a typecode indicator, a marshaling function identifier, and an unmarshaling function identifier, are used to enable modules of application code to be shared between different objects, thereby facilitating servant invocation by increasing the amount of commonized code in the operating system. In another aspect of the invention, a server invocation object is used in the execution of a method call. In still another aspect of the invention, a commonized code base is used to process typecode interpreted and compiled calls to a server process.

Abstract: The present invention provides an elegant and compact way to provide mechanisms for invocation of objects by client applications and for argument passing between client applications and object implementations, which reduce the memory space required for the client-side stubs, without the client application or the operating system knowing the details of how these mechanisms work. Moreover, these mechanisms function in a distributed computer environment with similar ease and efficiency, where client applications may be on one computer node and object implementations on another. Additionally the invention is independent of the particular C++ compiler used for generation of the stub code. The mechanism used to reduce this memory space comprises a stub generator (called "CONTOCC"), a data base of client-side stub description files and a stub-interpreter which knows how to read these client-side stub description files. CONTOCC reads interface definition language ("IDL") files and generates corresponding C++ files.

Abstract: A data structure for dynamically associating a service dependent representation with a servant object at run time is used in a distributed object computing system that incorporates subcontracts. Subcontracts supply different functionalities to objects. The data structure exists before run time, and is used at run time to perform the dynamic association. An arrangement also exists at run time. The structure comprises a service representation class representing a single subcontract, a servant base class associated with servant objects created at run time, and a linking mechanism to form a run time link between the server rep class and a servant object at run time. The server rep class provides functionality unique to a subcontract. At run time, servant objects are instantiated from the servant base class or a more derived class. The servant object uses the functionality provided by a subcontract by way of the linking mechanism.

Abstract: Data structures, methods, and devices for facilitating servant invocation in a distributed client-server based object oriented operating system are disclosed. In one aspect of the invention, descriptor data structures, which contain a typecode indicator, a marshaling function identifier, and an unmarshaling function identifier, are used to enable modules of application code to be shared between different objects, thereby facilitating servant invocation by increasing the amount of commonized code in the operating system. In another aspect of the invention, a server invocation object is used in the execution of a method call. In still another aspect of the invention, a commonized code base is used to process typecode interpreted and compiled calls to a server process.

Abstract: A method for enabling an application program to communicate with a network server, includes the steps of downloading a document from a document server to the application program, downloading code from a code server associated with the document server to the application program, the code including a network protocol handler for the network server, and using the network protocol handler to communicate with the network server.

Abstract: The method and apparatus for generating and employing a run-time generated stub to reference an object in an object oriented system. This method and apparatus represents in a first virtual machine a remote object implemented in a second virtual machine by employing a stub class. An object reference is sent by the second virtual machine and received by the first virtual machine. The object reference includes an interface descriptor that identifies the interface(s) of the remote object and an object handle that identifies the remote object. At run-time, the information associated with the remote object is transformed into a stub class that represents the remote object and implements only those interfaces identified by the interface descriptor and also defined by the first virtual machine. After the stub class is created, an instance of that stub class is generated and provided to the first virtual machine.

Abstract: A method for handling method calls in a client/server computer system includes the step of receiving at a server computer a method call generated by a client computer. The server computer then attempts to execute the method call and subsequently generates an exception. The exception is passed to the client computer. The client computer matches the exception to exceptions in an exception list stored in the client computer to obtain an exception object identifier. The exception object identifier is used to load exception code into the client computer. The exception code is then processed. Thus, the exception code need not be loaded at the time of generating the method call. Instead, it is only loaded when it is required at run time.

Abstract: A client/server computer apparatus includes a large number of client computers connected to a transmission channel. The client computers generate method calls that are applied to the transmission channel. Each method call may be encoded with a different communication protocol. A server computer processes each method call from the transmission channel by initially locating within each method call a method descriptor specified in a protocol-dependent format. The method descriptor is then compared to a list of protocol-dependent values stored in the memory of the server computer. An index value is assigned upon matching the method descriptor to a selected protocol-dependent value in the list of protocol-dependent values. The index value is passed to a protocol-independent portion of the server computer. The protocol-independent portion of the server computer executes the method corresponding to the index value to generate a reply.

Abstract: The invention provides solutions to the problems which are encountered by object oriented systems designers when attempting to implement schemes for object invocation and for argument passing in distributed systems wherein the arguments may be objects, and wherein the system supports a multiplicity of ORB-specific data formats, in ways which do not lock the object oriented base system into methods which may be difficult to change at a later time.

Abstract: A distributed computer system in which a server application performs operations responsive to operation requests from a client application. The client application initially identifies an operation for the server application to perform with a short identifier of the operation. If the short identifier is ambiguous, the server application sends the client application a reply indicating that the short identifier was ambiguous. The client application responds by sending a long identifier which uniquely identifies the operation. Preferably, the short identifier of an operation is derived by performing a hash function on the long identifier of the operation. In object-oriented distributed systems, the operations are methods defined in objects supported by the server application.