Method, apparatus, and program for a state machine framework

• US 7,010,778 B2
• Filed: 06/24/2002
• Issued: 03/07/2006
• Est. Priority Date: 06/24/2002
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Cook, John A.
• Primary Examiner(s): Zhen, Wei Y.
• Assistant Examiner(s): RAMPURIA, SATISH
• Application Number:
  US10/179,329
• Publication Number:
  US 20030237027A1
• Time in Patent Office: 1,352 Days
• Field of Search: 717106-108, 717/175, 717/146, 717/140, 717/117, 719/318, 370/352, 370/401, 370/463, 709/318, 713/323, 707/200, 707/103.R, 700/86, 715/315, 715/316
• US Class Current: 717/106
• CPC Class Codes: G06F 8/36 Software reuse

Abstract

A programming framework is provided for designing and implementing software state machines. A state machine initializer may be created that defines the states, conditions, actions, triggers, and state transitions for the software state machines. A set of user interfaces, may also be provided for creating initializers. An abstract state machine object may then be created that creates an instance of a particular state machine initializer. The state machine initializer acts as a helper to the state machine object, which uses the initializer to create an array of state transition objects. A set of programming interfaces may also be provided to define the programming framework. Events generated by one state machine may be used as triggers by another state machine. Furthermore, state values of one state machine may be used as inputs by other state machines. State machines may also share triggers and inputs.

Claims

1. A data processing system implemented method for providing a software state machine that is responsive to at least one input and at least one trigger, wherein the software state machine provides at least one output event based upon a current state of the software state machine and the at least one input, comprising:

providing a first state machine object, wherein the first state machine object is configured to use a first initializer object to execute a first software state machine, wherein the first software state machine comprises (i) a state table that defines states that the first software state machine may take, (II) an actions table that defines actions that the first software state machine may take, (iii) an inputs table that defines inputs to the first software state machine that affect state transitions within the first software state machine, (iv) a triggers table that defines triggers that initiate operation of the first software state machine, (v) an events table that defines output events that may be generated by the first software state machine, (vi) a state transitions table that defines stats transitions of the first software state machine, conditions that cause the state transitions, end the output events that are generated when the state transitions complete, and (vii) a conditions table that defines logical conditions that are examined in conjunction with entries in the state transition table; and

providing a second state machine object, wherein the second state machine object is configured to use a second initializer object to execute a second software state machine,

wherein the second state machine object is configured to interact with the first state machine abject based on the second initializer object.

2. The meted of claim 1, wherein the second state machine object is configured to embed the first state machine object.

3. The method of claim 1, wherein the second state machine object is a subclass of the first state machine object.

4. The method of claim 1, wherein the second state machine object shares a common input with the first state machine object, wherein the common input is used in determining a next state of each of the first software state machine and the second software state machine during execution of the first software state machine and the second software state machine.

5. The method of claim 1, wherein the second software state machine shares a common trigger with the first software state machine, the common trigger invoking an internal operation within both first software state machine and the second software state machine.

6. The method of claim 1, wherein the first software state machine generates at least a first event and outputs a state value, and wherein the second software state machine (i) receives she first event as a trigger that initiates operation of the second software state machine, and (ii) receives the state value as an input for use in determining a next state of the second software state machine.

7. The method of claim 6, wherein the first software state machine generates at least a first event, and wherein the second software state machine receives the first event as a trigger.

8. The method of claim 6, wherein the first software state machine generates at least a first event and outputs a state value, and wherein the second software state machine receives the state value as an input for use in determining a next state of the second software state machine.

9. The method of claim 6, wherein the first software state machine generates at least a first event and outputs a state value, and wherein the state value is accessible to a software object outside of the second state machine object.

10. The method of claim 1, further comprising:

providing a third state machine object, wherein the third state machine object is configured to use a third initializer object to execute a third software state machine,

wherein the third state machine object is configured to interact with the second state machine object based on the third initializer object.

11. The method of claim 10, wherein the third state machine object is a subclass of the second state machine object.

12. The method of claim 10, wherein the third state machine object is configured to embed both the first state machine object and the second state machine object.

13. An apparatus for providing a software state machine that is responsive to at least one input and at least one trigger, wherein the software state machine provides at least one output event based upon a current state of the software state machine and the at least one input, comprising:

a processor; and

a memory having stored therein a first state machine object, a first initializer object, a second state machine object, and a second initializer object,

wherein the first state machine object is configured to use the first initializer object to execute a first software stare machine, wherein the first software state machine comprises (i) a state table tat defines states that the first software state machine may take, (ii) an actions table that defines actions that the first software state machine may take, (iii) an, inputs table that defines inputs to the first software state machine that affect state transitions within the first software state machine, (iv) a triggers table that defines triggers that initiate operation of the first software state machine, (v) an events table that defines output events tat may be generated by the first software state machine, (vi) a state transitions table that defines state transitions of the first software state machine, conditions that cause the state transitions, and the output events that are generated when the state transitions complete, and (vii) a conditions table that defines logical conditions that are examined in conjunction with entries in the state transition table;

wherein the second state machine object is configured to use the second initializer object to execute a second software state machine; and

wherein the second state machine object is configured to interact with the first state machine object based on the second initializer object.

14. The apparatus of claim 13, wherein the second state machine object is configured to embed the first state machine abject.

15. The apparatus of claim 13, wherein the second state machine object is a subclass of the first state machine object.

16. The apparatus of claim 13, wherein the second state machine object shares a common input with the first state machine object, wherein the common input is used in determining a next state of each of the first software state machine and the second software state machine during execution of the first software state machine and the second software state machine.

17. The apparatus of claim 13, wherein the second software state machine shares a common trigger with the first software state machine, the common trigger being operable for invoking an internal operation within both first software state machine and the second software state machine.

18. The apparatus of claim 13, wherein the first software state machine generates at least a first event and outputs a state value, and wherein the second software state machine (i) receives the first event as a trigger that initiates operation of the second software state machine, and (ii) receives the state value as an input for use in determining a next state of the second software state machine.

19. The apparatus of claim 18, wherein the first software state machine generates at least a first event, and wherein the second software state machine receives the first event as a trigger.

20. The apparatus of claim 18, wherein the first software state machine generates at least a first event and outputs a state, value, and wherein the second software state machine receives the state value as an input for use in determining a next state of the second software, state machine.

21. The apparatus of claim 18, wherein the first software state machine generates at least a first event and outputs a state value, and wherein the state value is accessible to a software object outside of the second state machine object.