Object-oriented multitasking system

• US 5,519,867 A
• Filed: 07/19/1993
• Issued: 05/21/1996
• Est. Priority Date: 07/19/1993
• Status: Expired due to Term

• Current Assignee: Apple Inc.
• Original Assignee: Taligent, Inc. (HP Inc.)
• Inventors: Bolton, Eugenie L., Nakano, Russell T., Chernikoff, Daniel F., Moeller, Christopher P.
• Primary Examiner(s): Oberley, Alvin E.
• Assistant Examiner(s): Chavis, John Q.
• Application Number:
  US08/094,673
• Time in Patent Office: 1,037 Days
• Field of Search: 395/650, 395/700
• US Class Current: 718/107
• CPC Class Codes: G06F 9/4488 Object-oriented

Abstract

An apparatus for enabling an object-oriented application to access in an object-oriented manner a procedural operating system having a native procedural interface is disclosed. The apparatus includes a computer and a memory component in the computer. A code library is stored in the memory component. The code library includes computer program logic implementing an object-oriented class library. The object-oriented class library comprises related object-oriented classes for enabling the application to access in an object-oriented manner services provided by the operating system. The object-oriented classes include methods for accessing the operating system services using procedural function calls compatible with the native procedural interface of the operating system. The computer processes object-oriented statements contained in the application and defined by the class library by executing methods from the class library corresponding to the object-oriented statements. The object-oriented application includes support for multi-tasking.

Claims

1. An apparatus for enabling an object-oriented application, said application including object-oriented statements, to access in an object-oriented manner a procedural operating system by use of said object-oriented statements, said system providing services, including procedural functions saved as executable program logic that are called to access said services, said apparatus comprising:

(a) a computer;

(b) a memory component in said computer;

(c) a code library, stored in said memory component, comprising means for storing said executable program logic in an object-oriented class library; and

means for interfacing said object-oriented application to said procedural operating system utilizing said executable program logic;

(d) means, in said computer, for processing said object-oriented statements by executing methods from said object-oriented class library corresponding to said object-oriented statements; and

(e) means, in said object-oriented class library, including object-oriented thread classes, for enabling said object-oriented application to access said services to spawn, control, and obtain information relating to a thread of execution.

2. The apparatus of claim 1, wherein said thread classes comprise a first object-oriented class encapsulating information necessary to create a new thread of execution, said first class being an abstract base class, and a second object-oriented class for enabling said application to spawn a new thread of execution on a task by passing a subclass of said first class to an instance of said second class, and for enabling said application to terminate, suspend, resume, and schedule an existing thread of execution, said second class having instances, said instances representing run-time processing entities in said computer.

3. The apparatus of claim 1, wherein said object-oriented class library comprises object-oriented task classes for enabling said application to access in an object-oriented manner said services to reference and control a task, said task representing an execution environment for at least one thread of execution associated with said task.

4. The apparatus of claim 3, wherein said task classes comprise a first task object-oriented class encapsulating attributes and operations of an existing task, said first task class including protected methods to enable run-time specific subclasses of said first task class to spawn new tasks.

5. The apparatus of claim 4, wherein said first task class comprises methods for enabling said application to determine whether a possible task exists, to suspend and resume said existing task, to terminate said existing task, to receive predetermined information relating to said existing task, to identify a thread of execution contained in said existing task, and to perform predetermined virtual memory operations in an address space associated with said existing task.

6. The apparatus of claim 5, wherein said object-oriented class library comprises an object-oriented thread class for enabling said application to create a new thread of execution, said task classes further comprising a second object-oriented task class, derived from said first task class, for enabling said application to spawn a new run-time specific task having a single thread of execution by passing an instance of said thread class to an instance of said second task class.

7. The apparatus of claim 1, wherein said object-oriented class library comprises object-oriented synchronization classes for enabling said application to access in an object-oriented manner said services to synchronize execution of said thread of execution.

8. The apparatus of claim 7, wherein said synchronization classes define counting semaphores for use in synchronizing the execution of said thread of execution, said synchronization classes comprising methods for enabling said application to acquire one or more of said counting semaphores in an exclusive mode or in a shared mode, and to release said counting semaphores after said counting semaphores are acquired.

9. The apparatus of claim 8, wherein said counting semaphores are recoverable.

10. The apparatus of claim 7, wherein said synchronization classes define a monitor lock for use in synchronizing said thread of execution, said synchronization classes comprising methods for enabling said application to acquire and release said monitor lock, and to block on a specified condition once said monitor lock is acquired, said application releasing said monitor lock when said application blocks on said specified condition, and after said application is unblocked, due to satisfaction of said specified condition, said application reacquiring said monitor lock before resuming execution.

11. The apparatus of claim 10, wherein said synchronization classes further comprise methods for enabling said application to perform a broadcast operation on a specified blocking condition when said application has acquired said monitor lock, said broadcast operation unblocking all of said threads of execution that are blocked on said specified blocking condition.

12. The apparatus of claim 7, wherein said object-oriented class library comprises object-oriented scheduling classes for enabling said application to access in an object-oriented manner said services to schedule execution of said thread of execution.

13. The apparatus of claim 12 in which an actual scheduling priority, a default scheduling priority, and a maximum scheduling priority are associated with said application, said scheduling classes defining one or more scheduling priorities, said object-oriented class library including methods for setting each of said actual, default, and maximum scheduling priorities of said application to one of said scheduling priorities.

14. The apparatus of claim 13, wherein said scheduling classes comprise an object-oriented class defining an idle scheduling priority adapted for use with said threads of execution that execute when said computer is substantially idle.

15. The apparatus of claim 13, wherein said scheduling classes comprise an object-oriented class defining a responsive scheduling priority adapted for use with highly responsive threads of execution that execute for short time periods, and that block following said short time periods.

16. The apparatus of claim 13, wherein said scheduling classes comprise an object-oriented class defining an interaction scheduling priority adapted for use with highly responsive threads of execution implementing an interface between a human operator and said computer.

17. The apparatus of claim 13, wherein said scheduling classes comprise an object-oriented class defining a long-term scheduling priority adapted for use with threads of execution that execute for long periods of time.

18. The apparatus of claim 13, wherein said scheduling classes comprise methods for enabling a task to specify a relative scheduling urgency of said task.

19. The apparatus of claim 1, wherein said object-oriented class library comprises object-oriented fault classes for enabling said application to access in an object-oriented manner said services to process system and user-defined processor faults.

20. The apparatus of claim 19, wherein said fault classes comprise a first object-oriented class defining a generic fault, said first class having virtual methods for setting a processor computer program logic and a fault computer program logic to thereby identify said generic fault, said first class representing an abstract base class.

21. The apparatus of claim 20, wherein said fault classes comprise a second object-oriented class, derived from said first object-oriented class, comprising non-virtual methods for setting said processor computer program logic and said fault computer program logic in accordance with information specific to a particular fault of a particular processor such that said second class represents a processor-specific fault, said non-virtual methods of said second class overriding said virtual methods of said first class.

22. The apparatus of claim 21, wherein said fault classes comprise an object-oriented class encapsulating information identifying a destination port, a fault message format, and fault types, said object-oriented class comprising methods for enabling said application to specify said destination port, said fault message format, and said fault types, and for enabling said application to instruct said operating system to send messages in said specified fault message format to said specified destination port when said specified fault types occur.

23. The apparatus of claim 19, wherein said fault classes comprise a first object-oriented class comprising methods for obtaining and returning a processing state of said thread of execution.

24. The apparatus of claim 23, wherein said fault classes comprise a second object-oriented class having methods for enabling said application to receive fault messages and to respond to received fault messages, said fault messages comprising information identifying a faulting task and said faulting task'"'"'s faulting thread of execution, and/or information of a faulting thread of execution'"'"'s state, said faulting thread of execution'"'"'s state being obtained by calling said methods of said first class.

25. An apparatus for providing an object-oriented interface to a procedural operating system, said system providing services including procedural functions saved as executable program logic that are called to access said services, said apparatus comprising:

(a) a computer;

a memory component in said computer;

(c) a code library, stored in said memory component, comprising means for storing said executable program logic in an object-oriented class library;

means for interfacing to an object-oriented application; and

said object-oriented class library defining object-oriented statements, said statements insertable into said application to enable said application to access said services during run-time execution of said application in said computer; and

(d) means, in said object-oriented class library, including object-oriented, thread classes for enabling said application to access in an object-oriented manner operating system services to spawn, control, and obtain information relating to a thread of execution.

26. The apparatus of claim 25, wherein said object-oriented class library comprises object-oriented task classes for enabling said application to access in an object-oriented manner said services to reference and control a task, said task representing an execution environment for at least one thread of execution associated with said task.

27. The apparatus of claim 26, wherein said object-oriented class library comprises object-oriented synchronization classes for enabling said application to access in an object-oriented manner said services to synchronize execution of threads of execution.

28. The apparatus of claim 27, wherein said object-oriented class library comprises object-oriented, scheduling classes for enabling said application to access in an object-oriented manner said services to schedule execution of said thread of execution.

29. The apparatus of claim 28, wherein said object-oriented class library comprises object-oriented, fault classes for enabling said application to access in an object-oriented manner said services to process system and user-defined processor faults.

30. An apparatus for providing an object-oriented interface to a procedural operating system, said system providing services including procedural functions saved as executable program logic that are called to access said services, said apparatus comprising:

(a) a computer;

(b) a memory component in said computer; and

(c) a code library, stored in said memory component, comprising means for storing said executable program logic in an object-oriented class library;

means for interfacing to an object-oriented application; and

said object-oriented class library comprising object-oriented thread classes, said thread classes comprising methods for accessing said services during run-time execution of said application in said computer, said thread classes having statements, said statements insertable into said application to enable said application to access said services to spawn, control, and obtain information relating to threads of execution.

31. The apparatus of claim 30, wherein said thread classes comprise a first object-oriented class encapsulating information necessary to create a new thread of execution said first class being an abstract base class, and a second object-oriented class for enabling said application to spawn a new thread of execution on a task by passing a subclass of said first class to an instance of said second class, and for enabling said application to terminate, suspend, resume, and schedule an existing thread of execution, said second class having instances, said instances representing run-time processing entities in said computer.

32. An apparatus for providing an object-oriented interface to a procedural operating system, said system providing services including procedural functions saved as executable program logic that are called to access said services, said apparatus comprising:

(a) a computer;

(b) a memory component in said computer; and

(c) a code library, stored in said memory component, comprising means for storing said executable program logic in an object-oriented class library;

means for interfacing to an object-oriented application; and

said object-oriented class library comprising object-oriented task classes, said task classes comprising methods for accessing said services during run-time execution of said application in said computer, said task classes having statements, said statements insertable into said application to enable said application to access said services to reference and control a task, said task representing an execution environment for at least one thread of execution associated with said task.

33. The apparatus of claim 32, wherein said task classes comprise a first object-oriented class encapsulating attributes and operations of an existing task, said first class including protected method to enable run-time specific subclasses of said first class to spawn new tasks.

34. The apparatus of claim 33, wherein said first class comprises methods for enabling said application to determine whether a possible task exists, to suspend and resume said existing task, to terminate said existing task, to receive predetermined information relating to said existing task, to identify a thread of execution contained in said existing task, and to perform predetermined virtual memory operations in an address space associated with said existing task.

35. The apparatus of claim 34, wherein the object-oriented class library comprises an object-oriented thread class for enabling said application to create a new thread of execution, and said task classes further comprising a second object-oriented task class, derived from said first class, for enabling said application to spawn a new run-time specific task having a single thread of execution by passing an instance of said thread class to an instance of said second task class.

36. An apparatus for providing an object-oriented interface to a procedural operating system, said system providing services including procedural functions saved as executable program logic that are called to access said services, said apparatus comprising:

(a) a computer;

(b) a memory component in said computer; and

(c) a code library, stored in said memory component, comprising means for storing said executable program logic in an object-oriented class library;

means for interfacing to an object-oriented application; and

said object-oriented class library comprising object-oriented synchronization classes, said synchronization classes comprising methods for accessing said services during run-time execution of said application in said computer, said synchronization classes having statements, said statements insertable into said application to enable said application to access said services to synchronize execution of threads of execution.

37. The apparatus of claim 36, wherein said synchronization classes define counting semaphores for use in synchronizing the execution of said thread of execution, said synchronization classes comprising methods for enabling said application to acquire one or more of said counting semaphores in an exclusive mode or in a shared mode, and to release said counting semaphores after said counting semaphores are acquired.

38. The apparatus of claim 37, wherein said counting semaphores are recoverable.

39. The apparatus of claim 37, wherein said synchronization classes define a monitor lock for use in synchronizing said thread of execution, said synchronization classes comprising methods for enabling said application to acquire and release said monitor lock, and to block on a specified condition once said monitor lock is acquired, said application releasing said monitor lock when said application blocks on said specified condition, and after said application is unblocked, due to satisfaction of said specified condition, said application reacquiring said monitor lock before resuming execution.

40. The apparatus of claim 39, wherein said synchronization classes further comprise methods for enabling said application to perform a broadcast operation on a specified blocking condition when said application has acquired said monitor lock, said broadcast operation unblocking all of said threads of execution that are blocked on said specified blocking condition.

41. An apparatus for providing an object-oriented interface to a procedural operating system, said system providing services including procedural functions saved as executable program logic that are called to access said services, said apparatus comprising:

(a) a computer;

(b) a memory component in said computer; and

(c) a code library, stored in said memory component, comprising means for storing said executable program logic in an object-oriented class library;

means for interfacing to an object-oriented application; and

said object-oriented class library comprising object-oriented, scheduling classes, said scheduling classes comprising methods for accessing said services during run-time execution of said application in said computer, said scheduling classes having statements, said statements insertable into said application to enable said application to access said services.

42. The apparatus of claim 41 in which an actual scheduling priority, a default scheduling priority, and a maximum scheduling priority are associated with said application, said scheduling classes defining one or more scheduling priorities, said object-oriented class library including methods for setting each of said actual, default, and maximum scheduling priorities of said application to one of said scheduling priorities.

43. The apparatus of claim 42, wherein said scheduling classes comprise an object-oriented class defining an idle scheduling priority adapted for use with said threads of execution that execute when said computer is substantially idle.

44. The apparatus of claim 43, wherein said scheduling classes comprise an object-oriented class defining a responsive scheduling priority adapted for use with highly responsive threads of execution that execute for short time periods, and that block following said short time periods.

45. The apparatus of claim 44, wherein said scheduling classes comprise an object-oriented class defining an interaction scheduling priority adapted for use with highly responsive threads of execution implementing an interface between a human operator and said computer.

46. The apparatus of claim 44, wherein said scheduling classes comprise an object-oriented class defining a long-term scheduling priority adapted for use with threads of execution that execute for long periods of time.

47. (Amended) The apparatus of claim 44, wherein said scheduling classes comprise methods for enabling a task to specify a relative scheduling urgency of said task.

48. An apparatus for providing an object-oriented interface to a procedural operating system, said system providing services including procedural functions saved as executable program logic that are called to access said services, said apparatus comprising:

(a) a computer;

(b) a memory component in said computer; and

(c) a code library, stored in said memory component, comprising means for storing said executable program logic in an object-oriented class library;

means for interfacing to an object-oriented application; and

said object-oriented class library comprising object-oriented fault classes, said fault classes comprising methods for accessing said services during run-time execution of said application in said computer, said fault classes having statements, said statements insertable into said application to enable said application to access said services to process system and user-defined processor faults.

49. The apparatus of claim 48, wherein said fault classes comprise a first object-oriented class defining a generic fault, said first class having virtual methods for setting a processor computer program logic and a fault computer program logic to thereby identify said generic fault, said first class representing an abstract base class.

50. The apparatus of claim 49, wherein said fault classes comprise a second object-oriented class, derived from said first object-oriented class, comprising non-virtual methods for setting said processor computer program logic and said fault computer program logic in accordance with information specific to a particular fault of a particular processor such that said second class represents a processor-specific fault, said non-virtual methods of said second class override said virtual methods of said first class.

51. The apparatus of claim 49, wherein said fault classes comprise an object-oriented class encapsulating information identifying a destination port, a fault message format, and fault types, said object-oriented class comprising methods for enabling said application to specify said destination port, said fault message format, and said fault types, and for enabling said application to instruct said operating system to send messages in said specified fault message format to the specified destination port when said specified fault types occur.

52. The apparatus of claim 49, wherein said fault classes comprise a first object-oriented class comprising methods for obtaining and returning a processing state of said thread of execution.

53. The apparatus of claim 52, wherein said fault classes comprise a second object-oriented class having methods for enabling said application to receive fault messages and to respond to received fault messages, said fault messages comprising information identifying a faulting task and said faulting task'"'"'s faulting thread of execution, and/or information of a faulting thread of execution'"'"'s state, said faulting thread of execution'"'"'state being obtained by calling said methods of said first class.