Inter java virtual machine (JVM) resource locking mechanism

• US 20030217092A1
• Filed: 05/16/2002
• Published: 11/20/2003
• Est. Priority Date: 05/16/2002
• Status: Active Grant

• Current Assignee: Oracle America, Inc. (Oracle Corporation)
• Original Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Inventors: Veselov, Pavel S.
• Granted Patent: US 7,131,120 B2
• Time in Patent Office: Days
• US Class Current: 718/106
• CPC Class Codes: G06F 9/52 Program synchronisation; Mutual exclusion, e.g. by means of semaphores

Abstract

A system and method of sharing a resource includes receiving a request for a shared resource in a locking repository. The request is from a requestor and the requestor is one of several applications. Each of the applications is running on one of several Java virtual machines (JVMs). The shared resource is locked to the requester, if the shared resource is identified as available in the master locking repository.

Claims

1. A method of sharing a resource comprising:

receiving a request for a shared resource in a locking repository, the request being from a requester, the requestor being one of a plurality of applications, wherein the plurality of applications are running on a plurality of JVMs;

determining if the shared resource is identified as available in a master locking repository; and

locking the shared resource to the requester, if the shared resource is identified as available in the master locking repository.

2. The method of claim 1, wherein the request identifies the requestor and identifies the shared resource being requested.

3. The method of claim 2, wherein identifying the shared resource being requested includes identifying a category of shared resources wherein the category of shared resources includes a plurality of shared resources.

4. The method of claim 3 wherein locking the shared resource to the requestor, if the shared resource is available includes locking the plurality of shared resources to the requestor if each one of the plurality of shared resources is available.

5. The method of claim 1, wherein the request includes a time stamp.

6. The method of claim 1 wherein the plurality of JVMs can be running on one or more computing platforms.

7. The method of claim 1 wherein if the shared resource is not available, then:

waiting until shared resource is available; and

locking the shared resource to the requester when the shared resource becomes available.

8. The method of claim 7, wherein the shared resource is locked to a selected requestor of a plurality of requesters, the selected requester having a higher priority than the remaining requestors in the plurality of requesters.

9. A method of unlocking a shared resource comprising:

receiving an unlock request from an unlock requestor, where in the unlock request includes a request to unlock a shared resource that was previously locked to a lock requestor;

determining if the unlock requestor is the same as the lock requestor; and

unlocking the shared resource if the unlock requestor is the same as the lock requestor.

10. A method for a requester application to select a shared resource comprising:

determining a current status of a first shared resource;

locking the first shared resource to the requestor application if the first shared resource is available.

11. The method of claim 10, wherein determining the current status of the first shared resource includes:

sending a status query to a locking repository; and

receiving a status response from the locking repository.

12. The method of claim 10, further comprising:

determining a current status of a second shared resource if the first shared resource is unavailable; and

locking the second shared resource to the requestor application if the second shared resource is available.

13. The method of claim 10, wherein locking the first shared resource includes:

sending a request for the first shared resource to a locking repository;

determining if the first shared resource is available; and

locking the first shared resource to the requestor in the locking repository.

14. A method of selecting a master locking repository comprising:

instantiating a first application, the first application including a first library;

sending a query for a master locking repository from the first library to a second library, if a second library has been instantiated in a second application;

instantiating a master locking repository in the first library, if the second library does not respond to the query; and

instantiating a slave locking repository in the first library, if the second library responds to the query.

15. The method of claim 14, wherein the second library will respond to the first query if the first library and the second library are the same type.

16. The method of claim 14, further comprising:

instantiating a plurality of applications, each one of the plurality of applications including a corresponding one of a plurality of libraries;

sending a query for a master locking repository from each one of the plurality of libraries to the master locking repository;

instantiating a corresponding plurality of slave locking repositories in each one of the plurality of libraries when the master locking repository responds to the query from each corresponding one of the plurality of libraries.

17. The method of claim 16, further comprising:

detecting a shutdown of the first application;

selecting one of the plurality of slave locking repositories as a new master locking repository;

transferring data in the master locking repository to the selected slave locking repository;

determining if the data transfer was successful;

designating the selected slave locking repository as the master locking repository, if the data transfer was successful.

18. The method of claim 17, wherein if the data transfer was unsuccessful, then:

selecting one of the plurality of slave locking repositories as a new master locking repository.

19. A system comprising:

a plurality of shared resources coupled to a first computing platform the first computing platform including;

a first Java virtual machine including a first application, the first application includes a first library object; and

a second Java virtual machine including a second application, the second application includes a second library object;

logic for receiving a request for a selected one of the plurality of shared resources in a master locking repository, the request being from the first application;

logic for determining if the shared resource is identified as available in a master locking repository; and

logic for locking the shared resource to the requester in the master locking repository, if the selected shared resource is is identified as available in the master locking repository.

20. The system of claim 19, wherein the first computing platform includes a plurality of computing platforms.

21. The system of claim 19, wherein the first library object includes the master locking repository if the first application was instantiated before the second application and wherein the second library includes a slave locking repository.

22. The system of claim 19, wherein the second library object includes the master locking repository if the second application was instantiated before the first application and wherein the first library includes a slave locking repository.