System and method for storing and retrieving objects

• US 6,484,247 B1
• Filed: 06/25/1999
• Issued: 11/19/2002
• Est. Priority Date: 06/25/1998
• Status: Expired due to Term

• Current Assignee: Intellution, Inc. (GE Fanuc Automation North America Incorporated)
• Original Assignee: Intellution, Inc. (GE Fanuc Automation North America Incorporated)
• Inventors: Gendron, Robert F., Jones, Stephen K.
• Primary Examiner(s): Hudspeth, David
• Assistant Examiner(s): TZENG, FRED
• Application Number:
  US09/340,337
• Time in Patent Office: 1,243 Days
• Field of Search: 711/124, 711/170, 711/206, 707/103, 707/103.R, 707/206, 709/332, 709/203, 501/151
• US Class Current: 711/170
• CPC Class Codes: G06F 9/4493 Object persistence

Abstract

A system and method for storage and retrieval of objects. The objects are stored on a permanent medium in a manner to allow for fast recovery of the objects from the medium. The objects are stored in a format that is structurally equivalent to the format of the objects on a volatile medium, such as memory of a general-purpose computer. Objects are stored according to a data relationship with other objects. The objects may be stored as a stream of objects and offset references. Offset references are converted to actual memory addresses as objects are retrieved into the volatile medium.

Claims

1. A method for storing an object hierarchy having a plurality of objects, the method comprising steps of:

a) storing, in a data stream located in a volatile memory, the data stream having a format, data of a first object having a reference to a second object;

b) storing, in the data stream, the reference to the second object in the data stream;

c) storing, in the data stream, data of the second object; and

d) storing each of the plurality of objects of the object hierarchy in a single data stream, the data stream being stored in a non-volatile memory in a format structurally equivalent to the format of the data stream located in the volatile memory.

2. The method of claim 1, wherein step b) includes a step of storing an offset address that indicates a location of the second object in the data stream.

3. The method according to claim 2, further comprising a step of determining the offset address from a volatile address of the second object.

4. The method according to claim 2, further comprising a step of determining offset addresses for each of the plurality of objects stored in the data stream.

5. The method of claim 1, wherein the data stream is a file.

6. The method of claim 1, wherein the data stream is a location in computer memory.

7. The method of claim 1, wherein the data stream is transmitted over a communications network.

8. The method according to claim 1, further comprising a step of allocating a block of storage space for two or more of the plurality of objects.

9. The method according to claim 1, wherein the first and second objects are stored in the data stream substantially the same format as the first and second objects appear in computer memory.

10. The method according to claim 9, wherein step b) includes a step of storing an offset address that indicates the location of the second object in the data stream.

11. The method according to claim 9, further comprising a step of determining offset addresses for each of the plurality of objects stored in the data stream.

12. The method according to claim 9, further comprising a step of replacing an actual address reference to the second object by an offset address to the second object.

13. The method according to claim 12, wherein the offset address is an offset from the beginning of the stream.

14. The method according to claim 1, and in an object-oriented system, the first object inherits data from the second object.

15. The method according to claim 1, further comprising a step of storing object class definitions in the stream.

16. The method according to claim 1, wherein in steps a), b), and c), data is stored in a serial format.

17. A data structure for storing instantiated objects of an object-oriented programming language produced by the method of claim 1, the data structure comprising:

immediate data of a first object;

immediate data of a second object; and

an offset reference from the first object to the second.

18. The data structure according to claim 17, further comprising a reference to a function table holding functions for the first object.

19. The data structure according to claim 17, further comprising a header indicating a state of the first and second objects.

20. The data structure according to claim 17, further comprising class description information.

21. The data structure according to claim 17, further comprising a third object and an offset reference to the third object.

22. The method of claim 1, further comprising:

storing, in the data stream, all data referenced by the first object.

23. A method for recovering an object hierarchy having a plurality of stored objects from storage media into computer memory, the method comprising:

allocating memory for the plurality of stored objects;

copying each of the plurality of stored objects of the object hierarchy from storage media into computer memory, wherein the format of the stored objects in computer memory is structurally equivalent to the format of the stored objects on the storage media; and

converting addresses of the stored objects to actual addresses in computer memory.

24. The method according to claim 23, wherein step a) includes collectively allocating memory for the plurality of objects.

25. The method according to claim 23, further comprising a step of adding, to each of the addresses of the stored objects, a value that represents a location of a beginning of an allocated data area in computer memory.

26. The method according to claim 23, further comprising a step of allocating a data area in computer memory for the plurality of stored objects.

27. The method according to claim 26, wherein a size of the data area allocated depends upon the size of the stored objects.

28. The method according to claim 23, wherein the copying step includes copying a stream of data representing the objects into computer memory.

45. The computer program product according to claim 28, wherein the data stream contains all data referenced by the first object.

29. A computer program product comprising a computer readable medium having computer program logic recorded thereon for enabling a processor in a computer system to store an object hierarchy having a plurality of objects, the computer program being adapted to cause the computer system to perform the steps of:

a) storing, in a data stream located in a volatile memory, the data stream having a format, data of a first object having a reference to a second object;

b) storing, in the data stream, the reference to the second object in the data stream;

c) storing, in the data stream, data of the second object; and

d) storing each of the plurality of objects of the object hierarchy in a single data stream, the single data stream being stored in a non-volatile memory in a format structurally equivalent to the format of the data stream located in the volatile memory.

30. The computer program product according to of claim 29, wherein step b) includes a step of storing an offset address that indicates a location of the second object in the data stream.

31. The computer program product according to claim 30, wherein the computer further performs a step of determining the offset address from a volatile address of the second object.

32. The computer program product according to claim 30, wherein the computer further performs a step of determining offset addresses for each of the plurality of objects stored in the data stream.

33. The computer program product of claim 29, wherein the data stream is a file.

34. The computer program product of claim 29, wherein the data stream is a location in computer memory.

35. The computer program product of claim 29, wherein the data stream is transmitted over a communications network.

36. The computer program product according to claim 29, wherein the computer further performs a step of allocating a block of storage space for two or more of the plurality of objects.

37. The computer program product according to claim 29, wherein the first and second objects are stored in the data stream substantially the same format as the first and second objects appear in computer memory.

38. The computer program product according to claim 37, wherein step b) includes a step of storing an offset address that indicates the location of the second object in the data stream.

39. The computer program product according to claim 37, wherein the computer further performs a step of determining offset addresses for each of the plurality of objects stored in the data stream.

40. The computer program product according to claim 37, wherein the computer further performs a step of replacing an actual address reference to the second object by an offset address to the second object.

41. The computer program product according to claim 40, wherein the offset address is an offset from the beginning of the stream.

42. The program product according to claim 29, and in an object-oriented system, the first object inherits data from the second object.

43. The computer program product according to claim 29, wherein the computer further performs a step of storing object class definitions in the stream.

44. The computer program product according to claim 29, wherein in steps a), b), and c), data is stored in a serial format.