The Spring Framework (a.k.a Spring) is a marvellous framework whose fundamental purpose is to manage the transport of dependencies from one part of an application to another. This capability is sometimes also called Inversion of Control (IoC). Instead of being manually copied around from object to object, your dependencies are declared in a configuration file (sometimes called a Spring bean configuration or an application context). At context startup time, these dependencies will be wired based on a topological sorting of the bean graph defined in the configuration file.
The Spring Framework and RSF#
The RSF framework is built out of a set of Spring contexts and generally aligns with many Spring idioms and APIs.
Spring Injection (IoC)#
RSF makes heavy use of Spring to inject dependencies into beans and parts of the application. All RSF applications have a standard Spring application context which can have Spring beans defined in it. Along with this, RSF defines a Request Scope Application Context (RSAC) which contains beans which are instantiated during the request only. Target List Aggregating Bean (TLAB) is a specialized application of some of the Spring injection concepts. A strong knowledge of IoC concepts and use of Spring is important when working with RSF. The best place to start is Chapter 3 of the Spring documentation.
Spring Web Flow#
Spring Web Flow (SWF) is a self-contained library which manages the flow of a multi-request sequence of operations performed by a single user of a webapp. The configuration is managed by an XML-formatted file listing the states and transition conditions forming the flow - this may make use of OGNL expressions to express complex predicates. Spring Web Flow is a form of "universal" application definition, whereby the application's structure becomes freed not only from a dependence on a particular web technology, but also on a particular delivery environment and even, in theory, programming language.