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I went to the Twin Cities Java Users Group meeting on The Spring Framework. It was inspiring because people were really enthusiastic about Spring and the speaker, Adam Waldal, was quite good.
Here are some notes:

1. He has seen huge (3 year) projects decide on Spring as their framework.
2. The big thing about Spring is that it is what is known as an Inversion of Control Container (IoC). As an IoC, Spring uses reflection to pull off either setter injection or constructor injection. Both of these are ways to completely decouple an object’s implementation from objects that it might spawn, with the new method, for instance. The upshot is that your business objects will not get infected with Spring code. Spring is hanging out nearby, listening for when it is needed. As one article puts it,
   

   The concept behind Inversion of Control is often expressed in the Hollywood Principle: “Don’t call me, I’ll call you.” IoC moves the responsibility for making things happen into the framework, and away from application code. Where configuration is concerned this means that while in traditional container architectures such as EJB, a component might call the container to say “where’s object X, which I need to do my work”, with IoC the container figures out that the component needs an X object, and provides it to it at runtime. The container does this figuring out based on method signatures (such as JavaBean properties) and, possibly, configuration data such as XML.

3. “Its not just for web applications anymore.” A lot of Swing developers are using spring
4. Spring differs from struts in that it codes around interfaces while struts extends concrete classes.
5. The reflection capabilities built into Spring allow unit testing to go much faster. Cactus - test everything would take long enough for his development team to go take a coffee break. With Spring, the same task takes less that one minute.
6. It is his belief that unit testing should be happening without the business objects having any knowledge of the container they are in (as in EJB) and should not need the container to run a test and Spring allows this.
7. Spring makes heavy use of patterns (which is good)
8. Spring works well with hibernate
9. EJB vs Spring. EJB sees a “Big chunk of code” it might reuse and ignores the fine grained reusable bits of code while Spring lets you drill down as close as you want in defining reusable bits of code.
10. Spring can be used with Aspect Oriented Programming (AOP) also known as byte code emitters
11. One guy in the audience gushed about how easy Spring was.
12. Eclipse has a Spring plug-in.
13. Spring can wrap itself around a struts implementation, but struts cannot wrap itself around another framework.
14. JMS was brought up a lot. I didn’t know what it was, so I looked it up. It is Java Messaging Service. A way for distributed clients to talk to one another.

This entry was posted on Wednesday, January 19th, 2005 at 10:28 pm and is filed under Computers. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.