Wrapper system for enabling a non-multitasking application to access shared resources in a multitasking environment

• US 5,465,363 A
• Filed: 12/30/1993
• Issued: 11/07/1995
• Est. Priority Date: 12/30/1993
• Status: Expired due to Fees

• Current Assignee: Apple Inc.
• Original Assignee: Object Technology Licensing Corporation (Apple Inc.)
• Inventors: Orton, Debra L., Rollin, Keith
• Primary Examiner(s): Kriess, Kevin A.
• Assistant Examiner(s): BUTLER, DENNIS
• Application Number:
  US08/176,148
• Time in Patent Office: 677 Days
• Field of Search: 395/153, 395/157, 395/650, 395/700, 364/280, 364/281.3, 364/281.7
• US Class Current: 718/107
• CPC Class Codes: G06F 8/24 Object-oriented

Abstract

A view system is disclosed which provides support a mechanism to provide a multitask-safe wrapper or objects which are not multitask safe. This mechanism makes it possible to use objects that are not task-safe in a multitasking environment without modifying or understanding the internal workings of the said objects. This mechanism is not view system-specific, but is provided and used by the view system to support such behavior.

Claims

1. An apparatus for processing a request generated by a non-multitasking application task to access a plurality of shared resources in a computer system having a processor, a storage attached to and under control of the processor and a multitasking operating system running in the storage and controlling the processor, the apparatus comprising:

(a) means controlled by the multitasking operating system for constructing a first multitasking wrapper object containing a plurality of non-multitasking target objects, each of the plurality of target objects containing data and logic for accessing one of the plurality of shared resources;

(b) means responsive to the request to access one of the plurality of shared resources for reserving one of the plurality of target objects which can access the one shared resource; and

(c) means responsive to the request for using the data and logic in the reserved target object for accessing the one shared resource.

2. An apparatus as recited in claim 1, wherein the one shared resource has an associated monitor lock for preventing simultaneous access by two tasks and wherein the first wrapper object has means responsive to the request for acquiring the monitor lock prior to reserving one of the plurality of target objects and means for releasing the monitor lock after the one shared resource has been accessed for enabling a plurality of tasks to access the one shared resource.

3. An apparatus as recited in claim 1, wherein the request is to access one of the shared resources having a particular resource type and wherein the plurality of shared resources are arranged in a plurality of resource groups in which each of the plurality of shared resources in a resource group has the same resource type and wherein the first wrapper object contains a pool of target objects associated with each resource group and wherein the reserving means is responsive to the request for reserving one of the target objects in a target object pool associated with a resource group having a requested resource type.

4. An apparatus as recited in claim 3, wherein the reserving means includes means responsive to the request for assigning a target object to the application task within the first wrapper object.

5. An apparatus as recited in claim 1, including means responsive to requests to access one of the plurality of shared resources for creating target objects in the first wrapper object wherein each target object is associated one-to-one with one of the shared resources.

6. An apparatus as recited in claim 2, including means controlled by the multitasking operating system for constructing a second multitasking a wrapper object containing a second plurality of non-multitasking target objects each of the second plurality of target objects containing data and logic for accessing one of the plurality of shared resources and means responsive to the request for acquiring the monitor lock for synchronizing operations with the first wrapper object.

7. An apparatus as recited in claim 1, wherein the plurality of shared resources include a resource object, with access, logic and data and wherein the resource object access logic and data is included in a target object to synchronize access to the resource object.

8. A method for processing a request generated by a non-multitasking application task to access a plurality of shared resources in a computer system with a processor, a storage attached to and under the control of the processor and a multitasking operating system running in the storage for controlling the processor, the method comprising the steps of:

(a) constructing a first multitasking wrapper object with the multitasking operating system the first wrapper object containing a plurality of non-multitasking target objects each of the plurality of target objects containing data and logic for accessing one of the plurality of shared resources;

(b) reserving one of the plurality of target objects which can access the one shared resource in response to the request to access one of the plurality of shared resources; and

(c) using the data and logic in the reserved target object for accessing the one shared resource.

9. A method as recited in claim 8, including the steps of;

(d) associating a monitor lock with the one shared resource for preventing simultaneous access by two tasks;

(e) using the wrapper object to acquire the monitor lock in response to the request and prior to reserving one of the plurality of target objects; and

(f) releasing the monitor lock after the one shared resource has been accessed for one shared resource for enabling a plurality of tasks to access the target object.

10. A method as recited in claim 8, wherein the request is to access one of the shared resources having a particular resource type and the method of the steps of:

(g) arranging the plurality of shared resources in a plurality of resource groups in which each of the plurality of shared resources in a resource group has the same resource type;

(h) creating a pool of target objects in the first wrapper object associated with each resource group; and

(i) reserving a one of the target objects in a target object pool associated with a resource group having a requested resource type.

11. A method as recited in claim 10, including the step of:

(j) assigning a target object to the application task within the first wrapper object.

12. A method as recited in claim 8, including the step of:

(k) creating target objects in the first wrapper object in response to requests to access one of the plurality of shared resources wherein each target object is associated one-to-one with one of the shared resources.

13. A method as recited in claim 9, including the steps of:

(l) constructing a second multitasking wrapper object containing a second plurality of non-multitasking target objects each of the second plurality of target objects containing data and logic for accessing one of the plurality of shared resources; and

(m) acquiring the monitor lock for synchronizing operations with the first wrapper object.

14. A method as recited in claim 8, wherein the plurality of shared resources include a resource object with access logic and data and wherein the method includes the step of:

(n) including the resource object access logic and data in a target object to synchronize access to the resource object.