Method, apparatus, and program for distributing a document object model in a web server cluster

• US 7,181,489 B2
• Filed: 01/10/2002
• Issued: 02/20/2007
• Est. Priority Date: 01/10/2002
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Lection, David B., Masselle, Eric L.
• Primary Examiner(s): Lim; Krisna
• Assistant Examiner(s): REILLY, SEAN M
• Application Number:
  US10/043,439
• Publication Number:
  US 20030131051A1
• Time in Patent Office: 1,867 Days
• Field of Search: 709201-207, 709217-226, 709/238, 709213-216, 709/230, 719313-315, 718/100, 707/103.R, 707103 X-103 Z
• US Class Current: 709/202
• CPC Class Codes: G06Q 10/10 Office automation; Time management

Abstract

An asynchronous, peer-to-peer design is provided for synchronizing data on machines within a cluster using messaging. The data may be represented in memory as a document object model in secondary storage. Messaging may be handled by a messaging system with topic destinations. The design supports persistence management, locking, and transactions with rollback, and maintains a uniform state for the data across all nodes and secondary storage at all times. Furthermore, barring catastrophic failure of all machines in the cluster and secondary storage, there is no possibility of losing committed data.

Claims

1. A computer implemented method for processing shared data comprising:

receiving a request to perform a task on shared data;

creating a work item message for the task; and

publishing the work item message to a messaging service by posting the work item message to a topic of the messaging service based on a type of the task, wherein the topic is a category by which messages in the messaging service are sorted, wherein the type of the task is one of an edit task for modifying an unlocked node and a locking task for locking an unlocked node, wherein posting the work item message to a topic comprises posting the work item message to an edit topic with a filter value set to all nodes, wherein the edit topic is a category identifying non-transaction requests for unlocked nodes.

2. A computer implemented method for processing shared data comprising:

receiving a request to perform a task on shared data;

creating a work item message for the task; and

publishing the work item message to a messaging service by posting the work item message to a topic of the messaging service based on a type of the task, wherein the topic is a category by which messages in the messaging service are sorted, wherein the type of the task is one of an edit task for modifying a locked node and an unlocking task for unlocking a locked node, wherein posting the work item message to a topic comprises posting the work item message to a transaction topic with a filter value set to a node originating the request, wherein the transaction topic is a category identifying transaction requests for locked nodes.

3. A computer implemented method for processing shared data comprising:

receiving a work item message from a messaging service by consuming the work item message from a topic of the messaging service, wherein the topic is a category by which messages in the messaging service are sorted;

processing the work item message based on the topic;

publishing a result to a result topic of the messaging service, wherein the result topic is a category identifying results of processing the work item message; and

wherein consuming the work item message from a topic comprises consuming the work item message from an edit topic, wherein the edit topic is a category identifying non-transaction requests for unlocked nodes, and wherein the work item message consumed from the edit topic has a filter value set to all nodes.

4. The computer implemented method of claim 3, further comprising placing the work item message in an edit queue, wherein the edit queue comprises a plurality of work item messages received from the messaging service.

5. The computer implemented method of claim 4, wherein processing the work item message comprises:

determining whether the work item message was created by a current server cluster node based on the filter value; and

performing a request task corresponding to the work item message if the work item message was created by the current server cluster node.

6. The computer implemented method of claim 5, wherein processing the work item message further comprises:

waiting until the work item message is removed from the edit queue if the work item message was not created by the current server cluster node.

7. The computer implemented method of claim 3, wherein the work item message comprises a locking request for locking an unlocked node.

8. The computer implemented method of claim 7, wherein processing the work item message comprises locking a portion of shared data.

9. A computer implemented method for processing shared data comprising:

receiving a work item message from a messaging service by consuming the work item message from a topic of the messaging service, wherein the topic is a category by which messages in the messaging service are sorted;

processing the work item message based on the topic;

publishing a result to a result topic of the messaging service, wherein the result topic is a category identifying results of processing the work item message; and

wherein consuming the work item message from a topic comprises consuming the work item message from a transaction topic, wherein the transaction topic is a category identifying transaction requests for locked nodes, and wherein the work item message consumed from the transaction topic has a filter value set to an identifier of a locking node.

10. The computer implemented method of claim 9, wherein processing the work item message comprises:

performing a request task corresponding to the work item message on a clone of at least a portion of shared data.

11. The computer implemented method of claim 9, wherein the work item message comprises an unlocking request for unlocking a locked node.

12. The computer implemented method of claim 11, wherein processing the work item message comprises unlocking at least a portion of shared data.

13. The computer implemented method of claim 12, wherein the result comprises a modified portion of the shared data.

14. A data processing system for processing shared data comprising:

a bus,

a storage device, wherein the storage device contains computer usable code;

a communications unit connected to the bus; and

a processing unit connected to the bus, wherein the processing unit executes the computer usable code to receive a request to perform a task on shared data;

create a work item message for the task; and

publish the work item message to a messaging service by posting the work item message to a topic of the messaging service based on a type of the task, wherein the topic is a category by which messages in the messaging service are sorted, and wherein the type of the task is one of an edit task for modifying an unlocked node and a locking task for locking an unlocked nodes wherein the processing unit, in executing the computer usable code to post the work item message to a topic of the messaging service based on a type of the task, executes the computer usable code to post the work item message to an edit topic with a filter value set to all nodes, wherein the edit topic is a category identifying non-transaction requests for unlocked nodes.

15. A data processing system for processing shared data comprising:

a bus,

a storage device, wherein the storage device contains computer usable code;

a communications unit connected to the bus; and

a processing unit connected to the bus, wherein the processing unit executes the computer usable code to receive a request to perform a task on shared data;

create a work item message for the task; and

publish the work item message to a messaging service by posting the work item message to a topic of the messaging service based on a type of the task, wherein the topic is a category by which messages in the messaging service are sorted, and wherein the type of the task is one of an edit task for modifying a locked node and an unlocking task for unlocking a locked node, wherein the processing unit, in executing the computer usable code to publish the work item message to a messaging service by posting the work item message to a topic of the messaging service based on a type of the task, executes the computer usable code to post the work item message to a transaction topic with a filter value set to a node originating the request, wherein the transaction topic is a category identifying transaction requests for locked nodes.

16. A data processing system for processing shared data comprising:

a bus,

a storage device, wherein the storage device contains computer usable code;

a communications unit connected to the bus; and

a processing unit connected to the bus, wherein the processing unit executes the computer usable code to receive a work item message from a messaging service by consuming the work item message from a topic of the messaging service, wherein the topic is a category by which messages in the messaging service are sorted;

process the work item message based on the topic;

publish a result to a result topic of the messaging service, wherein the result topic is a category identifying results of processing the work item message; and

wherein the processing unit, in executing the computer usable code to receive a work item message from a messaging service by consuming the work item message from a topic of the messaging service, executes the computer usable code to consume a work item message from an edit topic, wherein the edit topic is a category identifying non-transaction requests for unlocked nodes, and wherein the work item message consumed from the edit topic has a filter value set to all nodes.

17. The data processing system of claim 16, wherein the processing unit further executes the computer usable code to place the work item message in an edit queue, wherein the edit queue comprises a plurality of work item messages received from the massaging service.

18. The data processing system of claim 17, wherein the processing unit, in executing the computer usable code to process the work item message based on the topic, executes the computer usable code to determine whether the work item message was created by a current server cluster node based on the filter value;

and

perform a request task corresponding to the work item message if the work item message was created by the current server cluster node.

19. The data processing system of claim 18, wherein the processing unit, in executing the computer usable code to process the work item message based on the topic, executes the computer usable code to wait until the work item message is removed from the edit queue if the work item message was not created by the current server cluster node.

20. The data processing system of claim 16, wherein the work item message comprises a locking request for locking an unlocked node.

21. The data processing system of claim 20, wherein the processing unit, in executing the computer usable code to process the work item message based on the topic, executes the computer usable code to lock a portion of shared data.

22. A data processing system for processing shared data comprising:

a bus,

a storage device, wherein the storage device contains computer usable code;

a communications unit connected to the bus; and

a processing unit connected to the bus, wherein the processing unit executes the computer usable code to receive a work item message from a messaging service by consuming the work item message from a topic of the messaging service, wherein the topic is a category by which messages in the messaging service are sorted;

process the work item message based on the topic;

publish a result to a result topic of the messaging service, wherein the result topic is a category identifying results of processing the work item message; and

wherein the processing unit, in executing the computer usable code to receive a work item message from a messaging service by consuming the work item message from a topic of the messaging service, executes the computer usable code to consume a work item message from a transaction topic, wherein the transaction topic is a category identifying transaction requests for locked nodes, and wherein the work item message consumed from the transaction topic has a filter value set to an identifier of a locking node.

23. The data processing system of claim 22, wherein the processing unit, in executing the computer usable code to process the work item message based on the topic, executes the computer usable code to perform a request task corresponding to the work item message on a clone of at least a portion of shared data.

24. The data processing system of claim 22, wherein the work item message comprises an unlocking request for unlocking a locked node.

25. The data processing system of claim 24, wherein the processing unit, in executing the computer usable code to process the work item message based on the topic, executes the computer usable code to unlock at least a portion of shared data.

26. The data processing system of claim 25, wherein the result comprises a modified portion of the shared data.

27. A computer program product for processing shared data, the computer program product comprising:

a computer usable storage medium having computer usable program code embodied therein, the computer useable program code comprising;

computer usable program code configured to receive a work item message from a messaging service by consuming the work item message from a topic of the messaging service, wherein the topic is a category by which messages in the messaging service are sorted and consuming the work item message from a topic comprises consuming the work item message from an edit topic, wherein the edit topic is a category identifying non-transaction requests for unlocked nodes, and wherein the work item message consumed from the edit topic has a filter value set to all nodes;

computer usable program code configured to process the work item message based on the topic; and

computer usable program code configured to publish a result to a result topic of the messaging service, wherein the result topic is a category identifying results of processing the work item message.