METHOD AND APPARATUS FOR EFFICIENT REPRESENTATION OF VARIABLE LENGTH IDENTIFIERS IN A DISTRIBUTED OBJECT SYSTEM

• US 20020029297A1
• Filed: 12/18/1997
• Published: 03/07/2002
• Est. Priority Date: 12/18/1997
• Status: Active Grant

• Current Assignee: Oracle America, Inc. (Oracle Corporation)
• Original Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Inventors: CAVANAUGH, KEN M.
• Granted Patent: US 6,516,354 B2
• Time in Patent Office: Days
• US Class Current: 719/315
• 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 for efficient representation of variable length object identifiers in a distributed object system having a client and an object server, the apparatus comprising:

a database containing a plurality of compact object identifiers;

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

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

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 has a fixed length.

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

7. 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.

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 variable length object identifiers.

9. 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.

10. Apparatus according to claim 1 wherein the distributed object system has a method for dynamically creating a portable object adapter and the ID server has a method responsive to a compact object identifier for retrieving a variable length object identifier from the database which retrieval method is called by the method for dynamically creating a portable object adapter in order to generate a name for the portable object adapter.

11. A method for efficient representation of variable length object identifiers in a distributed object system having a client and an object server, the method comprising the steps of:

(a) constructing a database containing a plurality of compact object identifiers;

(b) retrieving compact object identifiers from the database in response to a variable length object identifier and returning one of the retrieved compact object identifiers which corresponds to the variable length identifier; and

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

12. A method according to claim 11 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.

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

(a1) storing the database in the memory.

14. A method according to claim 11 wherein step (b) is performed with an ID server that has persistent state.

15. A method according to claim 11 wherein step (a) comprises the step of:

(a2) constructing a database in which each of the plurality of compact object identifiers has a fixed length.

16. A method according to claim 11 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.

17. A method according to claim 11 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.

18. A method according to claim 11 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.

19. A method according to claim 11 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.

20. A method according to claim 11 further comprising the steps of:

(e) retrieving a variable length object identifier from the database in response to a compact object identifier; and

(f) dynamically creating a portable object adapter using the variable length identifier to form the portable object adapter name.

21. A computer program product for efficient representation of variable length object identifiers in a distributed object system having a client and an object server, 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 compact object identifiers;

program code for retrieving compact object identifiers from the database in response to a variable length object identifier and returning one of the retrieved compact object identifiers which corresponds to the variable length identifier; and

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

22. A computer program product according to claim 21 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.

23. A computer program product according to claim 21 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.

24. A computer program product according to claim 21 further comprising:

program code for retrieving a variable length object identifier from the database in response to a compact object identifier; and

program code for dynamically creating a portable object adapter using the variable length identifier to form the portable object adapter name.