Programming Jakarta Struts, 2nd Edition [Electronic resources] نسخه متنی

Chapter 5. Struts Controller Components

As discussed in Chapter 1, the controller components
are responsible for detecting user input, possibly updating the
domain model, and selecting the next view for the client. The
controller helps to separate the presentation of the model from the
model itself. This separation gives you much more freedom to develop
a variety of presentations based on a single domain model.

Using a controller provides a centralized point of control where all
client requests are initially processed. Centralizing control in this
way realizes two requirements of MVC design. First, the controller
acts as the mediator/translator between client input and the model,
providing common functionality such as security, logging, and other
important services on behalf of each client request. Second, because
all requests are filtered through the controller, the view is
decoupled both from the business logic and from other view
components. The view returned to the client is entirely up to the
controller. This makes your applications much more flexible.

The Struts framework uses a servlet to process incoming requests.
However, it relies on many other components that are part of the
controller domain to help carry out its responsibilities. The Struts
controller components were mentioned briefly in previous chapters,
but it's time to take an in-depth look at what
components have responsibility for the controller functionality in
the framework.