Professional BlazeDS: Creating Rich Internet Applications with Flex® and Java®

9.1. Contextual Overview

To understand the extension point architecture, it is best to review the BlazeDS server-side architecture first. That way, the overall context and environment of the adapters is well understood. You are familiar with the BlazeDS server-side architecture from the last few chapters. Here, I only rapidly recap the key aspects of that architecture.

BlazeDS is a Java web application. It receives requests and messages from a Flex application via its Java Servlets–based endpoint. An endpoint is accessible via a URL. Each endpoint supports communication with a particular channel type, which represents the client side of Flex application. A particular channel is distinguished by the protocol and data exchange format it supports. For example, a channel-endpoint pair could support binary transmission over AMF or text-based exchange using AMFX. Also, a channel-endpoint pair could support pure request-response communication, exchange of messages, or request polling. Once a request or message arrives via an endpoint, it is intercepted and handled by the message broker, which is the central coordinator of all communications in BlazeDS. The message broker routes requests and messages to services and destinations. A service and destination pair acts as the server-side target for a message from a Flex client. For example, a RemotingService is the target of a message from a Flex RemoteObject. Associated with this RemotingService is a configured RemotingDestination. The service ...