System and method for applying visitor lock and persistent lock flags to control units of work boundaries in an object oriented environment

• US 5,488,721 A
• Filed: 05/19/1995
• Issued: 01/30/1996
• Est. Priority Date: 01/26/1993
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Shackelford, Floyd W., Rich, William L.
• Primary Examiner(s): Black, Thomas G.
• Assistant Examiner(s): AMSBURY, WAYNE P
• Application Number:
  US08/444,654
• Time in Patent Office: 256 Days
• Field of Search: 395/600
• US Class Current: 717/108
• CPC Class Codes: G06F 9/4493 Object persistence
• CPC Class Codes: G06F 9/526 Mutual exclusion algorithms
• CPC Class Codes: Y10S 707/955 Object-oriented
• CPC Class Codes: Y10S 707/99944 Object-oriented database structure

Abstract

Boundary control of units of work in an object oriented computing environment is provided by a visitor locking system and method and a persistent object locking system and method. The object management table includes a visitor lock flag and a persistent lock flag for each unit of work. The object manager prevents copying of an object from a first unit of work to a second unit of work in response to the visitor lock flag associated with the first unit of work being in a first state, and allows copying of the object from the first unit of work to the second unit of work in response to the visitor lock flag being in a second state. The object manager also locks an object from a first unit of work in response to the persistent lock flag associated therewith being in a first state, and unlocks the object from the first unit of work in response to the persistent lock flag being in a second state. Copying and locking may apply to persistent objects only. Locking may prevent addition of objects to, and deletion of objects from, the unit of work.

Claims

1. An object management system for an object oriented computing environment on a computing platform, said object oriented computing environment including a plurality of objects each including an object frame containing data attributes, and at least one object method for performing actions on the associated object, at least some of said objects being organized into a plurality of units of work, such that the objects in a unit of work are manipulated as a group to perform a task, said object management system comprising:

an object management table, including a listing of said plurality of units of work and pointers to the objects contained therein, said object management table further including a visitor lock flag for each of said plurality of units of work, each visitor lock flag being in one of a first state and a second state, and a persistent lock flag for each of said plurality of units of work, each persistent lock flag being in one of a first state and a second state;

visitor locking means for preventing copying of an object from a first unit of work to a second unit of work in response to the visitor lock flag associated with said first unit of work being in said first state, and for allowing copying of said object from said first unit of work to said second unit of work in response to the visitor lock flag associated with said first unit of work being in said second state; and

object locking means for locking an object within said first unit of work in response to the persistent lock flag associated with said first unit of work being in said first state, and for unlocking said object from said first unit of work in response to the persistent lock flag associated with said first unit of work being in said second state.

2. The object management system of claim 1 wherein said object locking means comprises means for preventing addition of an object to said first unit of work in response to the persistent lock flag associated with said first unit of work being in said first state, and for allowing addition of an object to said first unit of work in response to the persistent lock flag associated with said first unit of work being in said second state.

3. The object management system of claim 1 wherein said object locking means comprises means for preventing deletion of an object from said first unit of work in response to the persistent lock flag associated with said first unit of work being in said first state, and for allowing deletion of an object from said first unit of work in response to the persistent lock flag associated with said first unit of work being in said second state.

4. The object management system of claim 1 wherein said object locking means comprises means for preventing change to an object in said first unit of work in response to the persistent lock flag associated with said first unit of work being in said first state, and for allowing change to an object in said first unit of work in response to the persistent lock flag associated with said first unit of work being in said second state.

5. The object management system of claim 1 wherein said computing platform includes volatile storage means, and wherein at least some of said objects are persistent objects which are stored in said volatile storage means, said object locking means comprising means for locking a persistent object from a first unit of work in response to the persistent lock flag associated with said first unit of work being in said first state, and for unlocking said persistent object from said first unit of work in response to the persistent lock flag associated with said first unit of work being in said second state.

6. The object management system of claim 5 wherein said object locking means further comprises means for preventing addition of a persistent object to said first unit of work in response to the persistent lock flag associated with said first unit of work being in said first state, and for allowing addition of a persistent object to said first unit of work in response to the persistent lock flag associated with said first unit of work being in said second state.

7. The object management system of claim 5 wherein said object locking means comprises means for preventing deletion of a persistent object from said first unit of work in response to the persistent lock flag associated with said first unit of work being in said first state, and for allowing deletion of a persistent object from said first unit of work in response to the persistent lock flag associated with said first unit of work being in said second state.

8. The object management system of claim 5 wherein said object locking means comprises means for preventing change to a persistent object in said first unit of work in response to the persistent lock flag associated with said first unit of work being in said first state, and for allowing change to a persistent object in said first unit of work in response to the persistent lock flag associated with said first unit of work being in said second state.

9. The object management system of claim 1 wherein said object management table includes an Object Management Table Unit of Work Information Class (OMTUC) table for listing the unit of work instance, and wherein said object lock flag is included in said OMTUC table.

10. The object management system of claim 1 wherein said computing platform includes nonvolatile storage means, and wherein at least some of said objects are persistent objects which are stored in said nonvolatile storage means, said visitor locking means comprising means for preventing copying of a persistent object from said first unit of work to said second unit of work in response to the visitor lock flag associated with said first unit of work being in said first state, for allowing copying of a persistent object from said nonvolatile storage means to said second unit of work in response to the visitor lock flag associated with said first unit of work being in said first state, and for allowing copying of said persistent object from said first unit of work to said second unit of work in response to the visitor lock flag associated with said first unit of work being in said second state.

11. The object management system of claim 10 wherein said object management table includes an Object Management Table Unit of Work Information Class (OMTUC) table for listing the unit of work instances, and wherein said visitor lock flag is included in said OMTUC table.

12. An object management method for an object oriented computing environment on a computing platform, said object oriented computing environment including a plurality of objects each including an object frame-containing data attributes, and at least one object method for performing actions on the associated object, at least some of said objects being organized into a plurality of units of work, such that the objects in a unit of work are manipulated as a group to perform a task, said object oriented computing environment further comprising an object management table, including a listing of said plurality of units of work and pointers to the objects contained therein, said object management table further including a visitor lock flag for each of said plurality of units of work, each visitor lock flag being in one of a first state and a second state, and a persistent lock flag for each of said plurality of units of work, each persistent lock flag being in one of a first state and a second state, said object management method comprising the steps of:

preventing copying of an object from a first unit of work to a second unit of work in response to the visitor lock flag associated with said first unit of work being in said first state;

allowing copying of said object from said first unit of work to said second unit of work in response to the visitor lock flag associated with said first unit of work being in said second state;

locking an object within said first unit of work in response to the persistent lock flag associated with said first unit of work being in said first state; and

unlocking said object from said first unit of work in response to the persistent lock flag associated with said first unit of work being in said second state.

13. The object management method of claim 12:

wherein said locking step comprises the step of preventing addition of an object to said first unit of work in response to the persistent lock flag associated with said first unit of work being in said first state; and

wherein said unlocking step comprises the step of allowing addition of an object to said first unit of work in response to the persistent lock flag associated with said first unit of work being in said second state.

14. The object management method of claim 12:

wherein said locking step comprises the step of preventing deletion of an object from said first unit of work in response to the persistent lock flag associated with said first unit of work being in said first state; and

wherein said unlocking step comprises the step of allowing deletion of an object from said first unit of work in response to the persistent lock flag associated with said first unit of work being in said second state.

15. The object management method of claim 12:

wherein said locking step comprises the step of preventing change to an object in said first unit of work in response to the persistent lock flag associated with said first unit of work being in said first state; and

wherein said unlocking step comprises the step of allowing change to an object in said first unit of work in response to the persistent lock flag associated with said first unit of work being in said second state.

16. The object management method of claim 12 wherein said computing platform includes volatile storage means, and wherein at least some of said objects are persistent objects which are stored in said volatile storage means;

said locking step comprising the step of locking a persistent object from a first unit of work in response to the persistent lock flag associated with said first unit of work being in said first state; and

said unlocking step comprising the step of unlocking said persistent object from said first unit of work in response to the persistent lock flag associated with said first unit of work being in said second state.

17. The object management method of claim 16:

wherein said locking step further comprises the step of preventing addition of a persistent object to said first unit of work in response to the persistent lock flag associated with said first unit of work being in said first state; and

wherein said unlocking step further comprises the step of allowing addition of a persistent object to said first unit of work in response to the persistent lock flag associated with said first unit of work being in said second state.

18. The object management method of claim 16:

wherein said locking step further comprises the step of preventing deletion of a persistent object from said first unit of work in response to the persistent lock flag associated with said first unit of work being in said first state; and

wherein said unlocking step further comprises the step of allowing deletion of a persistent object from said first unit of work in response to the persistent lock flag associated with said first unit of work being in said second state.

19. The object management method of claim 16:

wherein said locking step further comprises the step of preventing change to a persistent object in said first unit of work in response to the persistent lock flag associated with said first unit of work being in said first state; and

wherein said unlocking step further comprises the step of allowing change to a persistent object in first unit of work in response to the persistent lock flag associated with said said first unit of work being in said second state.

20. The object management method of claim 12 wherein said computing platform includes nonvolatile storage means, and wherein at least some of said objects are persistent objects which are stored in said nonvolatile storage means;

said preventing step comprising the steps of;

preventing copying of a persistent object from said first unit of work to said second unit of work in response to the visitor lock flag associated with said first unit of work being in said first state; and

allowing copying of a persistent object from said nonvolatile storage means to said second unit of work in response to the visitor lock flag associated with said first unit of work being in said first state; and

said allowing step comprising the step of allowing copying of said persistent object from said first unit of work to said second unit of work in response to the visitor lock flag associated with said first unit of work being in said second state.