Method and apparatus for efficient representation of variable length identifiers in a distributed object system

• US 6,516,354 B2
• Filed: 12/18/1997
• Issued: 02/04/2003
• Est. Priority Date: 12/18/1997
• Status: Expired due to Term

• Current Assignee: Oracle America, Inc. (Oracle Corporation)
• Original Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Inventors: Cavanaugh, Ken M.
• Primary Examiner(s): Courtenay, III, St. John
• Assistant Examiner(s): BULLOCK JR, LEWIS ALEXANDER
• Application Number:
  US08/993,204
• Publication Number:
  US 20020029297A1
• Time in Patent Office: 1,874 Days
• Field of Search: 395/705, 709/303, 709/315, 709/316, 709/203, 709/200, 709/219, 707/103.R
• US Class Current: 719/316
• CPC Class Codes: G06F 9/465 Distributed object oriented systems remote method invocation [RMI] G06F9/548
• CPC Class Codes: Y10S 707/99944 Object-oriented database structure

Abstract

In a CORBA distributed object system, potential object name ambiguities in the Portable Object Adapter are resolved without using variable-length object identifiers by translating the variable length identifiers into a fixed length compact identifier, such as a integer. The mapping for persistent objects is maintained on an ID server with persistent state and the mappings are ultimately written to a file. A server IDL interface is defined to the ID server which interface includes a method that accepts a variable length fully qualified name and returns the compact identifier. The method assigns an identifier if one does not exist. Another method accepts the identifier and returns the name.

Claims

1. Apparatus fore efficient representation of variable length object identifiers in a distributed object system having a client and an object server with a method for dynamically crating a portable object adapter, the apparatus compressing:

a database containing a plurality of fixed-length compact object identifiers that are unique only to a particular portable object adapter and variable light object identifiers that are unique throughout the distributed object system;

an ID server having a method responsive to a variable length object identifier for retrieving fixed-length compact object identifiers from the database and returning one of the retrieved fixed-length compact object identifiers which corresponds to the variable length identifier;

an IDL interface available to the object server for invoking the ID server method over the distributed object system; and

wherein the method for dynamically creating a portable object adapter invokes the IDL interface when a server object instance does not exist in order to create a server object instance in the portable object adapter using a variable length identifier and assign thereto a previously-assigned fixed-length compact object identifier.

2. Apparatus according to claim 1 wherein the client comprises an object invocation mechanism which uses the one retrieved compact identifier returned from the ID server to identify an object implementation in the object server and to invoke a method in the identified object implementation.

3. Apparatus according to claim 1 wherein the distributed object system has a memory and the database is stored in the memory.

4. Apparatus according to claim 1 wherein the ID server has persistent state.

5. Apparatus according to claim 1 wherein each of the plurality of compact object identifiers comprises a fixed length integer.

6. Apparatus according to claim 1 wherein the database comprises a plurality of variable length object identifier/compact object identifier pairs and wherein the ID server searches the plurality of pairs to locate a given variable length object identifier and returns the corresponding compact object identifier of the pair.

7. Apparatus according to claim 1 wherein the database comprises a plurality of variable length object identifier/compact object identifier pairs and a dictionary built on the variable length object identifiers.

8. Apparatus according to claim 1 wherein the database comprises a plurality of variable length object identifier/compact object identifier pairs and a dictionary built on the compact object identifiers.

9. A method for efficient representation of variable length object identifiers in a distributed object system having a client and an object server with a method for dynamically creating a portable object adapter, the method comprising the steps of:

(a) constructing a database containing a plurality of fixed-length compact object, identifiers that are unique only to a particular portable object adapter and variable length object identifiers that are unique throughout the distributed object system;

(b) constructing an ID server for managing the database, the ID server having a method for retrieving fixed-length compact object identifiers from the database in response to a variable length object identifier and returning one of the retrieved fixed-length compact object identifiers which corresponds to the variable length identifier;

(c) defining an IDL interface available to the object server for invoking the ID server method over the distributed object system; and

(d) using the method for dynamically creating a portable object adapter to invoke the IDL interface when a server object instance does not exist in order to createa server object instance in the portable object adapter using a variable length identifier and assigning thereto a previously-assigned fixed-length compact object identifier.

10. A method according to claim 9 wherein the client comprises an object invocation mechanism and the method further comprises the step of:

(d) using the one compact object identifier returned from the ID server to identify an object implementation in the object server and to invoke a method in the identified object implementation.

11. A method according to claim 9 wherein the distributed object system has a memory and step (a) comprises the step of:

(a1) storing the database in the memory.

12. A method according to claim 9 wherein step (b) is performed with an ID server that has persistent state.

13. A method according to claim 9 wherein step (a) comprises the step of:

(a3) constructing a database in which each of the plurality of compact object identifiers comprises a fixed length integer.

14. A method according to claim 9 wherein the database comprises a plurality of variable length object identifier/compact object identifier pairs and wherein step (b) comprises the steps of:

(b1) searching the plurality of pairs to locate a given variable length object identifier; and

(b2) returning the corresponding compact object identifier of the pair.

15. A method according to claim 9 wherein the database comprises a plurality of variable length object identifier/compact object identifier pairs and wherein step (a) comprises the step of:

(a4) building a dictionary on the variable length object identifiers.

16. A method according to claim 9 wherein the database comprises a plurality of variable length object identifier/compact object identifier pairs and wherein step (a) comprises the step of:

(a5) building a dictionary on the compact object identifiers.

17. A computer program product for efficient representation of variable object identifiers in a distribution object system having a client and an object server with a method for dynamically creating a portable object adapter, the computer program product comprising a computer usable medium having computer readable program code thereon, including:

program code for constructing a database containing a plurality of fixed-length compact object identifiers that are unique only to a particular portable object adapter and variable length object identifiers that are unique throughout the distributed object system;

program code which constructs an ID server for managing the database, the ID server having a method for retrieving fixed-length compact object identifiers from the database in response to a variable length object identifier and returning one of the retrieved fixed-length compact object identifiers which corresponds to the variable length identifier;

program code for defining an IDL interface available to the object server for invoking the ID server method over the distributed object system; and

program code for using the method for dynamically creating a portable object adapter to invoke the IDL interface when aserver object instance does not exit in order create a server object instance in the portable o using a variable length identifier and assigning thereto a previously-assigned fixed-length compact object identifier.

18. A computer program product according to claim 17 wherein the client comprises an object invocation mechanism and the computer program product further comprises program code for using the one retrieved compact object identifier returned from the ID server to identify an object implementation in the object server and to invoke a method in the identified object implementation.

19. A computer program product according to claim 17 wherein the program code for constructing a database comprises program code for constructing a database in which each of the plurality of compact object identifiers comprises a fixed length integer.

20. A computer data signal embodied in a carrier wave for efficient representation of variable length object identifiers in a distributed object system having a client and an object server with a method for dynamically creating a portable object adapter, comprising:

program code for constructing a database containing a plurality of fixed-length compact object identifiers that are unique only to a particular portable object adapter and variable length object identifiers that are unique throughout the distributed object system;

program code which constructed an ID server for managing the database, the ID server having a method for retrieve fixed-length compact object identifiers from the database in response to variable length object identifier and returning one of the retrieved fixed-length compact object identifiers which corresponds to the variable length identifier;

program code for defining an IDL interface available to the object server for invoking the ID server method over the distributed object system; and

program code for using the method for dynamically creating a portable object adapter to invoke the IDL interface when a server object instance does not exist in order to create a server object instance in the portable object adapter using a variable length identifier and assigning thereto a previously-assigned fixed-length compact object identifier.

21. The computer data signal as defined in claim 20 wherein the client comprises an object invocation mechanism and the data signal further comprises program code for using the one retrieved compact object identifier returned from the ID server to identify an object implementation in the object server and to invoke a method in the identified object implementation.