When processing asynchronous requests in previous releases of WebSphere Process Server (hereafter called Process Server), failed events will be generated if there are any runtime errors. The recovery system keeps generating the failed events as the requests flow into faulty or unavailable service that is throwing the runtime errors. Once the runtime errors are resolved, the administrator will have to resubmit the failed events using either the admin console or scripts that use the failed event manager (FEM) API. This is a resource intensive operation to generate and resubmit failed events. In Process Server V7.0, the problem is elegantly addressed by the introduction of the store-and-forward feature.
When a component calls a service and the service is unavailable, the runtime errors are thrown. These runtime errors result in failed events being generated in the case of asynchronous calls. Instead of generating the failed events for subsequent service calls, users can configure the store-and-forward feature on the appropriate import or export or component so that the requests are stored in the corresponding queues. These stored requests will not be submitted to the faulty or unavailable target service anymore. This avoids generating a large number of failed events. Once the target service becomes available, the stored requests can be relayed using the Store and Forward widget in the business space.
The tutorial demonstrates the configuration of this feature in applications that run on Process Server V7.0. It presents various scenarios with sample applications that illustrate how the feature works at runtime. The business space widgets that correspond to the store-and-forward feature are presented.
The tutorial is divided into the following sections:
- Introduction to store-and-forward feature
- The store-and-forward feature in various business application scenarios
- Exception specification in the store-and-forward configuration
- A good understanding of J2EE concepts.
- Skilled in developing applications for WebSphere Process Server using WebSphere Integration Developer (hereafter called Integration Developer) and performing administrative activities on the server environment.
- Knowledge of WebSphere MQ and its tools.
The following environment is required to run the samples.
- One Windows® XP® Service Pack 2 desktop with at least 2 GB of RAM
- IBM® WebSphere Integration Developer V18.104.22.168 Fix Pack 1 with the test environment. You need to apply interim fix IZ72101 for the test environment.
- IBM WebSphere Process Server V22.214.171.124 Fix Pack 1
- WebSphere MQ V6.0