Method and system for locking resources in a distributed environment

Abstract

A method and system that creates and maintains lock properties for a resource or object in a distributed environment. The lock properties provide other client computer systems limited availability to the locked resource. Limited availability relates to being able to only read, write or delete the resource, or any combination thereof. Additionally, these lock properties allow other client computer systems to simultaneously hold or share equivalent locks. Other lock properties relate to advisory or mandatory status for the lock. Advisory locks may be honored or ignored by other client computer systems.

1 . A computer storage medium having stored thereon a locked resource accessed with a Distributed Authoring and Versioning (DAV) protocol message, wherein the DAV protocol is an extension of Hypertext Markup Language (HTTP), and wherein the locked resource comprises:
 a data object to store object data; and   a lock object, wherein the lock object is associated with the data object, and wherein the lock object comprises information relating to a type of lock on the associated data object, and wherein the lock object further comprises a property that is of a noshare type.   
   
   
       2 . A computer storage medium as defined in  claim 1 , wherein the property is a noshareread type. 
   
   
       3 . A computer storage medium as defined in  claim 1 , wherein the property is a nosharedelete type. 
   
   
       4 . A computer storage medium as defined in  claim 1 , wherein the property is a nosharewrite type. 
   
   
       5 . A computer storage medium as defined in  claim 1 , wherein the lock object services a lock token request. 
   
   
       6 . A computer storage medium as defined in  claim 1 , wherein a services layer processes an access request for the data object. 
   
   
       7 . A method of locking a resource in a distributed environment communicating in a Distributed Authoring and Versioning (DAV) protocol, wherein the DAV protocol is an extension of Hypertext Markup Language (HTTP), the method comprising:
 sending a request in the DAV protocol to access a resource, wherein the resource comprises a data object, and wherein the request originates from an application program;   processing the request;   causing the creation of a lock object having a predetermined type, wherein the predetermined type is one from the group consisting of a nosharewrite, a noshareread, and a nosharedelete;   receiving a lock token upon the creation of the lock object; and   accessing the resource.   
   
   
       8 . A method as defined in  claim 7 , wherein the application program is a client application program operating on a client system. 
   
   
       9 . A method as defined in  claim 7 , wherein the application program is part of a server system. 
   
   
       10 . A method as defined in  claim 7 , wherein the application program causes the creation of the lock object. 
   
   
       11 . A method as defined in  claim 7 , wherein a services layer creates the lock object and associates the lock object with the data object. 
   
   
       12 . A method as defined in  claim 7 , wherein the act of processing the request comprises:
 determining whether the resource is locked by another application program; and   determining the type of access requested.   
   
   
       13 . A method as defined in  claim 7 , wherein the lock is advisory. 
   
   
       14 . A method as defined in  claim 7 , wherein a plurality of application programs can cause the creation of a lock on the resource. 
   
   
       15 . A system for creating and managing a lock object in a distributed environment communicating in a Distributed Authoring and Versioning (DAV) protocol, wherein the DAV protocol is an extension of Hypertext Markup Language (HTTP), the computer system comprising:
 an application program, the application program operable to send a request in the DAV protocol to access a data object; and   a services layer, the services layer operable to determine a type of access requested for the data object and to determine if the data object is associated with the lock object, wherein the lock object comprises a locktype property.   
   
   
       16 . A system as defined in  claim 15 , wherein the services layer is further operable to:
 determine whether access may be given for the data object for the type of access requested;   if access may be given for the type of access requested, returning a lock token; and   if access may not be given for the type of access requested, denying access.   
   
   
       17 . A system as defined in  claim 15 , wherein the locktype property is a nosharewrite lock. 
   
   
       18 . A system as defined in  claim 15 , wherein the locktype property is a nosharedelete lock. 
   
   
       19 . A system as defined in  claim 15 , wherein the locktype property is a noshareread lock. 
   
   
       20 . A system as defined in  claim 15 , wherein the locktype property is an advisory lock.