Method and apparatus for executing event driven simulations

• US 7,631,108 B2
• Filed: 05/13/2005
• Issued: 12/08/2009
• Est. Priority Date: 05/13/2004
• Status: Active Grant

• Current Assignee: Oracle America, Inc. (Oracle Corporation)
• Original Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Inventors: Kesselman, Jeffrey P., Twilleager, Doug
• Primary Examiner(s): Jaroenchonwanit; Bunjob
• Assistant Examiner(s): Fan; Hua
• Application Number:
  US11/129,219
• Publication Number:
  US 20050266926A1
• Time in Patent Office: 1,670 Days
• Field of Search: 709/250, 709230-231, 709205-207, 712/208, 719/313
• US Class Current: 709/250
• CPC Class Codes: A63F 13/12 involving interaction between a plurality of game devices, e.g. transmisison or distribution systems protocols for networked virtual reality, networked games H04L29/06034
• CPC Class Codes: A63F 13/30 Interconnection arrangements between game servers and game devices; Interconnection arrangements between game devices; Interconnection arrangements between game servers
• CPC Class Codes: A63F 2300/531 Server assignment
• CPC Class Codes: G06F 17/00 Digital computing or data processing equipment or methods, specially adapted for specific functions information retrieval, database structures or file system structures therefor G06F16/00
• CPC Class Codes: G06F 2111/02 CAD in a network environment, e.g. collaborative CAD or distributed simulation
• CPC Class Codes: G06F 30/20 Design optimisation, verification or simulation optimisation, verification or simulation of circuit designs G06F30/30
• CPC Class Codes: G06F 9/466 Transaction processing

Abstract

A system that includes an object store layer configured to store a plurality of objects, wherein each of the plurality of objects comprises a method, a communication layer configured to receive an event from a user and generate a task based on the event, and a simulation layer configured to retrieve one of the plurality of objects responsive to execution of the task and execute the method associated with the one of the plurality of objects.

Claims

1. A system comprising:

a master object store configured to store a plurality of objects corresponding to a multiplayer game environment, wherein each of the plurality of objects comprises a method; and

a plurality of computer systems for manipulating the multiplayer game environment, wherein each computer system of the plurality of computer systems executes a stack, and wherein the stack comprises;

a cache for storing a subset of the plurality of objects from the object store layer;

a communication layer component configured to;

receive an event from a user manipulating the multiplayer game environment;

generate a task based on the event; and

place the task in a task queue; and

a simulation layer component configured to;

obtain the task from the task queue,

load an initial object of the plurality of objects corresponding to the task from the cache when the initial object is in the cache,

load the initial object from the master object store when the initial object is not in the cache,

assign a transactional context and execution thread to the task, wherein the transactional context comprises a time stamp portion and a random number portion,

execute the task by the execution thread, wherein executing the task comprises executing the method in the initial object to generate a modified initial object,

request a dependent object of the plurality of objects using the initial method;

retrieve the dependent object, wherein retrieving the dependent object comprises checking for a dead-lock condition, wherein checking for the dead-lock condition comprises;

determining whether an interrupt flag of the task is set, wherein the interrupt flag is set to false when the task is created;

if the interrupt flag of the task is not set;

 

setting the interrupt flag for the task, if the dependent object is locked and a dependent object time stamp is greater than a task time stamp; and

 

waiting to retrieve the dependent object; and

if the interrupt flag of the task is set;

 

aborting a transaction associated with the task; and

 

re-queuing the tasking in the event queue; and

commit the modified initial object to the master object store to update the multiplayer game environment.

2. The system of claim 1, wherein the communications layer component of the stack executing on one of the plurality of computer systems is operatively connected to the communications layer component of the stack executing on another of the plurality of computer systems.

3. The system of claim 1, wherein the cache of the stack executing on one of the plurality of computer systems is operatively connected to the cache of the stack executing on another of the plurality of computer systems.

4. The system of claim 1, wherein the cache component is configured to retrieve and send at least one of the objects to the master object store, wherein the master object store is shared across the plurality of computer systems.

5. The system of claim 1, wherein each of the plurality of objects is a serializable object.

6. The system of claim 1, wherein the cache locks the one of plurality of objects retrieved from the cache.

7. The system of claim 1, wherein the simulation layer further comprises an execution engine configured to execute the task.

8. The system of claim 1, wherein the communication layer comprises functionality to allow one user to communicate with another user.

9. The system of claim 1, wherein the communication layer comprises functionality to load balance the system.

10. A computer readable medium, encoded with software instructions executable by a processor on a computer system, for executing a task, wherein the executing the task comprises:

receiving, by the computer system, an event generated by a user manipulating a multiplayer game environment while connected to the computer system;

queuing the task corresponding to the event in a task queue on the computer system;

removing the task from the task queue;

requesting an initial object corresponding to the task from a cache on the computer system;

retrieving the initial object from an object store layer, wherein the object store layer comprises a master object store shared by a plurality of computer systems and a cache on the computer system, wherein the cache is configured to store a subset of the plurality of objects from the object store layer, wherein the initial object is retrieved from the cache when the initial object is in the cache, wherein the initial object is retrieved from the master object store when the initial object is not in the cache, and wherein the computer system is one of the plurality of computer systems;

assigning a transactional context and execution thread to the task, wherein the transactional context comprises a time stamp portion and a random number portion;

executing, by the execution thread, an initial method present in the initial object to generate a modified initial object;

requesting a dependent object using the initial method;

retrieving the dependent object, wherein retrieving the dependent object comprises checking for a dead-lock condition, wherein checking for the dead-lock condition comprises;

determining whether an interrupt flag of the task is set, wherein the interrupt flag is set to false when the task is created;

if the interrupt flag of the task is not set;

setting the interrupt flag for the task, if the dependent object is locked and a dependent object time stamp is greater than a task time stamp; and

waiting to retrieve the dependent object; and

if the interrupt flag of the task is set;

aborting a transaction associated with the task; and

re-queuing the tasking in the event queue; and

commit the modified initial object to the object store layer to update the multiplayer game environment,

wherein the plurality of computer systems modify a same multiplayer game represented in the master object store.

11. The computer readable medium of claim 10, further comprising:

executing the dependent object;

returning the dependent object to the object store layer;

completing execution of the initial method; and

returning the modified initial object to the master object store.

12. The computer readable medium of claim 11, wherein retrieving the dependent object comprises at least one selected from the group consisting of a get command and a peek command.

13. The computer readable medium of claim 10, wherein the dependent object time stamp corresponds to the time stamp of a task that has currently locked the dependent object.

14. The computer readable medium of claim 10, wherein checking for the dead-lock condition occurs whenever a time stamp is updated.