1. Spring Framework Kansas City Java User’s Group Jason W. Bedell July 12, 2006

2. Overview • J2EE Alternative • Inversion of Control (IoC) vs. Dependency Injection (DI) • Aspect Oriented Programming (AOP) • Spring Modules • Example Application • Dependency Injection Example • AOP Example • Real-World Application – DI & AOP

3. J2EE Alternative • Heavyweight complexity • An easier way to connect disparate components • Enterprise Services using POJO’s • Other players: PicoContainer, HiveMind, Avalon

4. IoC and Dependency Injection • IoC an earlier, more general term • Think “plug-ins” • Behavior is configured instead of programmed. • Dependency Injection is a pattern to achieve IoC • Alternative patterns: Service Locator

5. Aspect Oriented Programming • “AOP enables modularization of crosscutting concerns” • AOP Terms: • Aspects • Joinpoints • Advice • Cutpoints • Introductions • Targets • Proxy • Weaving • Alternative AOP Containers: AspectJ, JBoss

6. AOP Terms • Aspects: • The modularized logic that is being applied throughout an application. • Examples: Logging, Security, Transaction Management, etc. • Joinpoints • An execution point where an aspect can be applied. • Examples: a method being called, a method returning, an exception being thrown, a field being modified, etc. • Advice • The actual implementation of an aspect. • Cutpoints • The joinpoints where advice should be applied. • Introductions • A method or attribute that you introduce to an existing class • Targets • A class that is being advised • Example: Course Service, Student Service, etc. • Proxy • The object created after applying advice to a target object. • Weaving • The process of applying aspects to target objects to create a new, proxied object. • Weaving can occur at compile time, classload time, runtime.

7. Spring Modules • The core container • Application context module • AOP Module • JDBC abstraction and DAO module • O/R mapping integration module (supports Hibernate, JDO, Oracle TopLink, Apache OJB, and iBATIS) • Web module • MVC framework

8. Example ApplicationDependency Injection (DI) Example

9. Example ApplicationAOP Example • Determine what Joinpoint to use as our Cutpoint • Implement the Aspect in the form of Advise • Define a Spring Advisor • Spring Advisor: the combination of advice that defines the aspect’s behavior and a pointcut defining where the aspect should be executed. • Spring allows you to define your own advisor or use a predefined, packaged advisor • Define your bean proxy • Inject your Advisor into the Proxy as an Interceptor

10. Real World ExampleDI & AOP • Application Tier • SpringMVC Framework • Tiles, JSTL • Service Tier • Service POJO Targets • Persistence Tier • DAO POJO Targets • Hibernate Framework • Security Aspect • Acegi Framework Advisor • Transaction Support Aspect • Spring Transaction Management Advisor