edu.ucsb.adl.middleware
Class CancelService

java.lang.Object
  |
  +--edu.ucsb.adl.middleware.CancelService

public final class CancelService

extends java.lang.Object

The ADL cancel service. Conceptually, this service cancels a currently-running query. The associated result set is marked as being complete, but is otherwise untouched.

This class reads the following properties from the main middleware configuration file. Property values may be indirectly specified using the notation @P where P is the name of another property (see ExtendedProperties for more information).

cancel.gatekeeper.class

The fully-qualified name of the service-level gatekeeper class, e.g., "edu.ucsb.adl.middleware.IPAddressGatekeeper".

cancel.gatekeeper.argument

The service-level gatekeeper's startup parameter.

Version:

$Header: /export/home/gjanee/middleware/edu/ucsb/adl/middleware/RCS/CancelService.java,v 1.4 2004/09/21 23:53:43 gjanee Exp $

$Log: CancelService.java,v $ Revision 1.4 2004/09/21 23:53:43 gjanee
Minor documentation change.

Revision 1.3 2004/03/05 18:52:05 gjanee
Added support for multiple middleware instances. A middleware instance is represented by a Global object that is tied to a main middleware configuration file. All service objects now maintain a reference to the appropriate Global object. Instance-wide variables formerly coded as class variables are now held by the Global object; various methods that return instance-wide variables now accept a Global object as an argument. The Global object is now passed to all service drivers.

Revision 1.2 2001/08/15 21:37:28 gjanee
Switched to the new configuration file structure. In the new structure, an entirely collection-independent "main" configuration file refers to a directory of subdirectories, one subdirectory per collection; each subdirectory holds a collection-specific middleware configuration file in addition to any configuration files required by the collection driver.

Revision 1.1 2000/01/30 23:00:57 gjanee
Initial revision

Author:

Greg Janée
Alexandria Digital Library

Method Summary

static edu.ucsb.adl.middleware.CancelService	createService(java.lang.String configurationFile) Creates a CancelService.
void	destroy() Decrements the reference count.
void	performCancelService(javax.servlet.ServletRequest request, int id) Performs the ADL cancel service.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

createService

public static edu.ucsb.adl.middleware.CancelService createService(java.lang.String configurationFile)
                                                           throws InternalErrorException

Creates a CancelService. If a service already exists for the configuration file, the extant service's reference count is incremented and it is returned instead.

Parameters:

configurationFile - The filename of a main middleware configuration file.

Throws:

InternalErrorException - If the initialization of the service fails.

performCancelService

public void performCancelService(javax.servlet.ServletRequest request,
                                 int id)
                          throws MiddlewareException

Performs the ADL cancel service. This method is multithread-safe.

Parameters:

request - The full request.

id - The query's ID. If the ID is invalid, the service does nothing.

Throws:

BadRequestException - If request is invalid.

NoAuthorizationException - If the request is valid but not allowed.

InternalErrorException - If the request cannot otherwise be completed.

MiddlewareException

destroy

public void destroy()

Decrements the reference count. When the reference count drops to zero, all resources held by the service are freed.