Package org.dspace.services.model

Interface RequestInterceptor

All Superinterfaces:

OrderedService

All Known Implementing Classes:

RequestInterceptorExample, SystemEventService.EventRequestInterceptor

public interface RequestInterceptor
extends OrderedService

Executes at the beginning and/or end of system requests.

Note that the ordering of these must be set specifically higher than 0 or an exception will occur. If you do not really care what the order is you are encouraged to use 10.

Note that the highest priority interceptor will be executed first in request start and last on request end. The lowest priority interceptor would be executed last on request start and first on request end. If you need an interceptor which can execute first on request start and first on request end (or vice versa) then create 2 interceptors. :-)

Author:

Aaron Zeckoski (azeckoski @ gmail.com)

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static class	RequestInterceptor.RequestInterruptionException	Indicate that request processing should be halted.

Method Summary

Modifier and Type	Method	Description
void	onEnd(String requestId, boolean succeeded, Exception failure)	Take actions after the request is handled for an operation.
void	onStart(String requestId)	Take actions before the request is handled for an operation.

Methods inherited from interface org.dspace.kernel.mixins.OrderedService

getOrder

Method Detail

onStart

void onStart(String requestId)

Take actions before the request is handled for an operation. This will be called just before each request is sent to the correct request handler. For example: starting a transaction would happen at this point.

If you want to interrupt the handling of this request (stop it) then throw a RequestInterceptor.RequestInterruptionException.

Parameters:

requestId - the unique id of the request

Throws:

RequestInterceptor.RequestInterruptionException - if this interceptor wants to stop the request

onEnd

void onEnd(String requestId,
           boolean succeeded,
           Exception failure)

Take actions after the request is handled for an operation. This will be called just before each operation is totally completed. For example: closing a transaction would happen at this point.

If you want to interrupt the handling of this request (stop it) then throw a RequestInterceptor.RequestInterruptionException.

NOTE: it is important to realize that this will be called even if the request fails. Please check the incoming success param to see if this request was successful or not. This is your cue to rollback or commit, for example.

Parameters:

requestId - the unique id of the request

succeeded - true if the request operations were successful, false if there was a failure

failure - this is the exception associated with the failure, it is null if there is no associated exception