HP Integrity NonStop H-Series - Manual (Page 42)

NOTE: Because JDBC Type 2 is a dynamic-link library (DLL), it is loaded as a part of the Spring
application process. However, when the JDBC Type 4 driver is used, the JDBC process runs as
a separate process external to the Spring application process.
Key Features of Spring
The key features offered by the Spring framework are as follows:
• Loose coupling
Spring provides a lightweight container that helps you to build a complex application by
integrating and wiring a set of loosely coupled Plain Old Java Objects (POJOs). It simplifies
the overall application development task by enabling you to develop software components,
test them in isolation, and then integrate and deploy them as Java EE or Java Standard
Edition (SE) applications.
• Simplified database connection and transaction management
Spring provides the pluggable DAO component for database connection and transaction
management, which facilitates the development of database applications by demarcating
the low-level integration issues. DAO includes support for common databases and transaction
management strategies, for JTA and single JDBC data source to connect with the SQL/MX
database on HP NonStop systems.
• Simplified integration with other popular frameworks
The layered architecture of the Spring framework makes it easy to integrate it with other
popular Java frameworks, such as Apache MyFaces (to build a robust and highly interactive
user interface) or Hibernate (for persistent database connection).
Spring Projects
The Spring community maintains several projects such as Spring Web Flow, Spring Web Services,
and Spring Security. Among these projects, only Spring Web Flow is presently certified for use
on the NonStop platform.
Spring Web Flow
Spring Web Flow is an MVC extension that enables you to define Controllers using a
domain-specific language. Traditionally, user interface (UI) flows in a web application are not
defined. Frameworks, such as Struts and Spring Web MVC, compel you to separate the UI flow
into individual controllers and views.
For instance, Struts maps a request to an action class. The action class then selects a view and
forwards the request to the view. This is a simple and functional system. However, this system
has a disadvantage because the overall UI flow of the web application is not clear from the action
definitions. Thus, the flexibility is hampered because the actions cannot be easily reused.
The Spring Web MVC framework offers a slightly higher level of functionality than the controllers
that implement a predefined work flow. However, these controllers are pre-defined for a general
work flow concept and hence cannot be reused.
In such situations, Spring Web Flow is advantageous because it allows you to represent the UI
flow in a web application in a clear, simple, and reusable format.
42 Spring Overview