IBM E02HMLL-I Implementation Guide - Page 29

- At startup, when it interacts with the InterChange Server Express to get its initial configuration. - During operation, when it receives directives from the connector controller to report its status, pause, stop, or resume. v Optionally, ORB-based communication can also be used for event delivery in a publish-and-subscribe interaction. In the IIOP request/response protocol, communication either succeeds or fails immediately, so both programs must be running for the components to communicate. However, for request/response interactions in an InterChange Server Express implementation, you can use a connector property to set a store-and-forward mode, specifying how a connector controller will respond to a collaboration's request in a situation where the connector agent is unavailable: v If you set the property to True, the connector controller won't fail any collaboration requests even if the connector agent is unavailable. A request is blocked until the connector agent is operational. This causes a collaboration to wait until the connector agent is operational before it completes the processing flow for the request. v If set to False, the connector controller fails all collaboration requests if the connector agent is unavailable. This causes a collaboration to complete the processing of the request according to its business logic for processing a failed request. Messaging technologies Messaging embodies a communication style in which programs asynchronously exchange discrete units of data (messages). Programs that use a messaging transport need not establish connections or wait for messages; each program asynchronously sends and receives messages by interacting with the messaging service. The messaging service provides guaranteed delivery, storing the message if the destination program is unavailable and retrying until it is available. Java Messaging Service (JMS) is supported as the messaging system. When JMS is the delivery transport mechanism, data persistence can be provided through the long-lived business processes feature. When this feature is used, a process initiated by a request on a collaboration can be placed in a waiting state with a timeout value, so that the process will be resumed if and when a specified data response is received. Use of this feature requires that the feature be enabled during the creation of the collaboration template. InterChange Server Express InterChange Server Express is a multi-threaded, Java-based execution framework for collaborations. InterChange Server Express runs within its own Java Virtual Machine (JVM). This section describes the following services and features of InterChange Server Express: v "Event management service" on page 18 v "Connector controllers" on page 18 v "Repository" on page 18 v "Database connectivity service" on page 18 v "Database connection pools" on page 18 v "Transactional collaborations" on page 18 v "Recovery features" on page 19 Chapter 1. Overview of IBM WebSphere Business Integration Server Express 17