20.2.2. Deploying Participants

Transactional web services and transactional clients are deployed by placing them in the application server deploy directory alongside the XTS service archive (SAR). The SAR exports all the client and web service API classes needed to manage transactions and enroll and manage participant web services. It provides implementations of all the WS-C and WS-T coordination services, not just the coordinator services. In particular, it exposes the client and web service participant endpoints which are needed to receive incoming messages originating from the coordinator.

Normally, a transactional application client and the transaction web service it invokes will be deployed in different application servers. As long as the XTS SAR is deployed to each of these containers XTS will transparently route coordination messages from clients or web services to their coordinator and vice versa. When the the client begins a transaction by default it creates a context using the coordination services in its local container. The context holds a reference to the local Registration Service which means that any web services enlisted in the transaction enrol with the coordination services in the same container."

The coordinator does not need to reside in the same container as the client application. By configuring the client deployment appropriately it is possible to use the coordinator services co-located with one of the web services or even to use services deployed in a separate, dedicated container. See Chapter 8 Stand-Alone Coordination for details of how to configure a coordinator located in a different container to the client.