US 5,341,478 AGranted

Methods and apparatus for providing dynamic invocation of applications in a distributed heterogeneous environment

AssigneeDigital Equipment Corporation

InventorsRobert L. Travis, Jr., Andrew P. Wilson, Neal F. Jacobson, Michael J. Renzullo

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Abstract

A method and apparatus providing for the interaction of processes in an object-oriented manner by which a system manages "classes" of data instances and applications rather than managing the data itself. The names of classes may be stored in a data base which also contains other information about the classes, such as certain con, non attributes of applications or instances which are supported by the classes. Applications can remotely invoke other applications by sending messages with parameters. Using the message names, as well as information about the classes of certain parameters and certain preference information, a reference to a specific method is selected from the data base. That method will perform the operation specified in the message. Other information in the data base is then used to locate and execute the actual code to implement the referenced method.

Claims14

Dependent claims

In a data processing network including a plurality of platforms for executing a plurality of applications, server ones of said applications being capable of performing operations, a method of invoking, in a server one of said plurality of platforms, one of said server applications requested by a client application running on a client one of said plurality of platforms, said method of invoking comprising the steps of:

providing a data base stored in a memory in the network, said data base having
a plurality of method entries each corresponding to one of said server applications and further containing a reference to a mechanism for invoking the corresponding server application to allow said server application to perform a specified operation on a specified instance,
a plurality of class entries each containing information identifying a uniquely identifiable class and a corresponding group of said method entries, each of the classes being referenced by a different set of instances which are items that may be manipulated or accessed by said client and server applications, with instances in the same class sharing common characteristics, and each class entry further containing an identification of one or more message entries, and
a plurality of message entries identified in said class entries, each specifying types of operations which can be performed on the instances associated with a corresponding class entry;
generating by the client one of said plurality platforms operating under the control of a first operating system and executing said client application, a request including an identifier for a selected instance and an identifier for a desired message;
using said data base to determine, from said request and its corresponding message and instance identifiers, an identifier for a corresponding method, said identifier for said corresponding method including a reference to a procedure to allow the server application to perform said desired operation on said first instance;
and
transmitting said identifier for said selected instance and said reference to said procedure, to the server one of said plurality of platforms, said server one of said plurality of platforms operating under the control of a second, different operating system.

5 more elements

A data processing network for allowing remote invocation of server applications by client applications in a object oriented manner comprising:

memory in the network containing a data base, said data base including:
a plurality of method entries each corresponding to a server application and further containing a reference to a mechanism for invoking a procedure to allow said server application to perform a specified operation on a specified instance,
a plurality of class entries, each containing information identifying a uniquely identifiable class and a corresponding group of said method entries, each of the classes being referenced by a different set of instances, which are items that may be manipulated or accessed by the server applications, with instances in the same class sharing common characteristics, and each class entry further containing an identification of a corresponding group of message entries, and
a plurality of message entries containing information specifying the types of operations which can be performed on instances in the corresponding classes;
and
a plurality of first platforms operating under the control of a first operating system, for executing the client applications;
a plurality of second platforms operating under the control of a second, different operating system for executing the server applications, the first platforms including
means for generating a request including an identifier for a selected instance and an identifier for a desired message,
data base control means, coupled to the memory in the network, for controlling the data base, the database control means including
means for selected a server application to be invoked as a result of said request;
means for determining an identifier for a first method from said request, the first method including a reference to a selected server application to perform the desired operation on the selected instance;
means for selecting one of said second platforms on which to invoke said selected server application;
and
means for transmitting to the selected one of the second platforms the reference to the selected server application via the identifier for the selected instance;
and with each of the plurality of second platforms including:
means for receiving the reference for the selected server application from the transmitting means in the data base control means.

13 more elements

Dependencies are inferred from the claim text.