Mechanism for resource allocation and for dispatching incoming calls in a distributed object environment

• US 6,282,581 B1
• Filed: 03/27/1997
• Issued: 08/28/2001
• Est. Priority Date: 03/27/1997
• Status: Expired due to Fees

• Current Assignee: Agilent Technologies, Inc., Hewlett-Packard Company (HP Inc.), Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Kirshenbaum, Evan, Moore, Keith E.
• Primary Examiner(s): COURTENAY III, ST JOHN
• Application Number:
  US08/825,070
• Time in Patent Office: 1,615 Days
• Field of Search: 709/200-253, 709/303, 709/106, 709/300, 709/310-330, 364/578, 395/653, 395/705, 717/8
• US Class Current: 719/316
• CPC Class Codes: G06F 9/548 Object oriented; Remote method invocation [RMI] non-remote method invocation G06F9/449

Abstract

A communications framework operable to support remote method invocation in a distributed object environment. The communications framework supporting a base class having an interface definition for a virtual query_op method, the interface definition specifying that the query_op method accepts a reference to a specifier for an operation to be performed, and that the query_op method returns a reference to a dispatch function to be invoked to perform the operation provided as an argument to an invocation of the query_op method, wherein the dispatch function accepts as arguments a reference to a target object on which to perform the operation and a reference to an object containing a list of values passed to and returned from the operation. A target object derives from the base class and provides an implementation for the query_op method.

Other systems and methods are disclosed.

Claims

1. A communications framework operable to support remote method invocation in a distributed object environment, comprising:

a base class having an interface definition for a virtual

query_op method, the interface definition specifying;

that the query_op method accepts a reference to a specifier for an operation to be performed; and

that the query_op method returns a reference to a dispatch function to be invoked to perform the operation provided as an argument to an invocation of the query_op method;

wherein the dispatch fuinction accepts as arguments a reference to a target object on which to perform the operation and a reference to an object containing a list of values passed to and returned from the operation; and

at least one target object deriving from the base class and providing an implementation for the query_op method.

2. The communication framework of claim 1,

wherein the transport is operable to invoke the query_op method of a first object; and wherein the query_op method returns a reference to an object to be passed as an argument to the dispatch function, which may be a reference to either the first object or a second object.

3. The commnunications framework of claim 1, further comprising:

a caller entity for calling the query_op method;

wherein an implementation of the query_op method is further operable to return a reference to an argument list and wherein the caller provides values for any arguments in the argument list that are input values to the d ispa tch function.

4. The communications framework of claim 1, wherein the argument list comprises:

a de-marshalling method operable to retrieve values from a communications channel and to cause such values to be entered into the argument list.

5. The communications framework of claim 1, wherein said query_op method is further operable to accept a quality of service input parameter indicative of the required or desired quality of service.

6. The communications framework of claim 1, wherein said query_op method is further operable to return quality of service information indicative of the quality of service available.

7. The communications framework of claim 1, further comprising:

a caller entity operable to invoke query_op on the target object;

wherein the query_op method is further operable to return a reference to an argument list;

wherein the query_op method is further operable to return a reference to an object on which to invoke the dispatch function;

wherein the caller entity is further operable to demarshall arguments received over a communications channel onto the argument list;

wherein the caller entity, responsive to receiving the reference for the dispatch function from the query_op method, is operable to invoke the dispatch function and to provide the dispatch function and argument list as parameters to the dispatch function.

8. The communications framework of claim 2, further comprising:

object protection means operable to protect the object referenced by the object reference returned from the dispatch function from destruction or invalidation.

9. The communications framework of claim 2 wherein the base class further comprises:

a declaration of an invoke method operable to accept the specifier and a reference to the source of the incoming arguments;

wherein if the query_op method fails to return a dispatch function, the remote procedure call transport executes the invoke method upon the object referred to by the object reference returned by the query_op method.

10. The communications framework of claim 3, wherein the caller entity is a remote procedure call transport.

11. The communications framework of claim 3, where in an implementation of the query_op method is further operable to receive a reference to an argument list from a caller entity and wherein the caller entity is operable to provide values for any arguments in the argument list that are input values to the dispatch function.

12. The communications framework of claim 3, wherein an implementation of the query_op method is further operable to create an argument list and is further operable to return a reference to the argument list and wherein the remote procedure call transport is operable to provide values for any arguments in the argument list that are input values to the dispatch function.

13. The communications framework of claim 5, wherein the remote procedure call transport supplies the quality of service information to the dispatch function.

14. The communications framework of claim 5, wherein the dispatch function is operable to return quality of service information to the remote procedure call transport.

15. The communications framework of claim 6, wherein the quality of service information includes a threading policy of the target object.

16. The communications framework of claim 6, wherein the remote procedure call transport responsive to the quality of service information, selectively, invokes the dispatch function, allocates resources, negotiate payments, checks authorization, sets priority for the dispatch function, sets deadlines for the dispatch function, allocates memory, schedules delivery of results from the dispatch function.

17. The communications framework of claim 7, wherein the caller entity is further operable receive a result from the dispatch function and to marshall the result onto the communications channel.

18. The communications framework of claim 12, further comprising:

at least one argument list create function associated with at least one operation wherein the argument list create function may be invoked by the query_op method and wherein the argument list create function is operable to create an argument list.

19. The communications framework of claim 15, wherein the remote procedure call transport executes in a first thread and responsive to the threading policy of the target object selectively invokes the dispatch function in a second thread.

20. The communications framework of claim 15, wherein the threading policy may specify a maximum number of methods of the target object that may be executed simultaneously, and responsive to the maximum, the remote procedure call transport, selectively, executes no more than the maximum number of methods of the target object simultaneously.

21. The communications framework of claim 17, wherein the arglist implements a release() method, where in the release() method is operable to indicate to the arglist that it may deallocate any memory used by the arglist;

and

wherein the caller entity is operable to call the release () method when the result has been marshalled onto the communications channel.

22. The communications framework of claim 21, further comprising a heap, and wherein an arglist created on the heap is operable to delete itself when the caller entity calls release() on the arglist.

23. A method of operating a communications framework, comprising the steps of:

identifying a target object;

calling a first method of the target object to allocate an argument list;

demarshalling arguments received on a communications channel onto the argument list;

demarshalling an identifier to a second method received on the communications channel;

calling a dispatch function to invoke the second method;

receiving a result from the dispatch function; and

marshalling the result onto the communications channel.

24. The method of claim 23, further comprising the step of:

returning from the first method an identifier for the dispatch function.

25. The method of claim 23, further comprising the step of:

returning from the first method an identifier of second object on which to invoke the dispatch function.