Tracking and propagating updates to a message-driven system of interdependent components

• US 6,817,019 B1
• Filed: 05/31/1996
• Issued: 11/09/2004
• Est. Priority Date: 05/31/1996
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Wang, I-Shin Andy, Lin, Jy-Jine James
• Primary Examiner(s): Lao, Sue
• Application Number:
  US08/655,879
• Time in Patent Office: 3,084 Days
• Field of Search: 395/672, 395/670, 395/683, 395/712, 395/188.01, 395/200.32, 395/200.78, 709/102, 709/100, 709/300, 709/303, 709/318, 709/310
• US Class Current: 719/318
• CPC Class Codes: G06F 9/542 Event management; Broadcasting; Multicasting; Notifications

Abstract

The present invention discloses a method, apparatus, and article of manufacture for tracking and propagating state changes in a message-driven computer program. In accordance with the present invention, a program in the memory of a computer receives a notification signal indicating that an event has occurred and transitions a first component from a current state to a new state based on the notification signal, wherein the states are represented by discrete objects or components. The computer program propagates, to a second component subordinate to a first component representing the new state, a signal indicating the new state of the first component.

Claims

1. A computer-implemented method for propagating state changes in a message-driven computer program comprising:

(a) receiving, in a computer, a first notification signal indicating that an event has occurred;

(b) transitioning a first component of an application program executing in the computer from a current state to a new state in response to the first notification sign;

(c) evaluating the state of a third component of the application program to determine if the transition of the first component to the new state should be propagated to a second component of the application program, wherein the second component is dependent on the first component;

(d) delaying propagating a second notification signal that indicates the state transition from the first component to the second component until the state of the third component indicates that the propagation should occur; and

(e) propagating the second notification signal from the first component to the second component by setting a flag in the second component, wherein the flag represents the state of the first component.

2. The method of claim 1 further comprising storing, in a queue, the second notification signal propagated to the second component.

3. The method of claim 1 wherein the event is an input/output event received into the computer.

4. The method of claim 1 wherein the state of the first component is represented by a discrete object that is mapped to the event.

5. An apparatus for propagating state changes in a message-driven computer program, wherein the computer program is comprised of a plurality of interdependent components, comprising:

(a) a computer having a memory;

(b) means, performed by the computer, for receiving a first notification signal indicating that an event has occurred;

(c) means, performed by the computer, for transitioning a first component from a current state to a new state in response to the first notification signal;

(d) means, performed by the computer, for evaluating the state of a third component to determine if the transition of the first component to the new state should be propagated to a second component, wherein the second component is dependent of the first component;

(e) means, performed by the computer, for delaying propagating a second notification signal that indicates the state transition from the first component to the second component until the state of the third component indicates that the propagation should occur; and

(f) means, performed by the computer, for propagating the second notification signal from the first component to the second component by setting a flag in the second component, wherein the flag represents the state of the first component.

6. The apparatus of claim 5, further comprising means, performed by the computer, for storing in a queue, in the memory of the computer, the second notification signal propagated to the second component.

7. The apparatus of claim 5, wherein the event is an input/output event received into the computer.

8. The apparatus of claim 5, wherein the state of the first component is represented by a discrete object that is mapped to the event.

9. A program storage device, readable by a computer having a memory and coupled to a data storage device, tangibly embodying one or more programs of instructions executable by the computer to perform a method of propagating state changes in a message-driven computer program executed by the computer, wherein the computer program is comprised of a plurality of interdependent components, the method comprising:

(a) receiving, in the memory of the computer, a first notification signal indicating that an event has occurred;

(b) transitioning, in the memory of the computer, a first component from a current state to a new state in response to the first notification signal;

(c) evaluating, in the memory of the computer, the state of a third component to determine if the transition of the first component to the new state should be propagated to a second component, wherein the second component is dependent on the first component;

(d) delaying, in the memory of the computer, propagating a second notification signal that indicates the state transition from the first component to the second component until the state of the third component indicates that the propagation should occur; and

(e) propagating, in the memory of the computer, the second notification signal from the first component to the second component by setting a flag in the second component, wherein the flag represents the state of the first component.

10. The program storage device of claim 9, the method further comprising storing in a queue, in the memory of the computer, the second notification signal propagated to the second component.

11. The program storage device of claim 9 wherein the event is an input/output event.

12. The program storage device of claim 9, wherein the state of the first component is represented by a discrete object that is mapped to the event.