I’ve been fairly quiet over the last couple of months as I’ve been working on a few items, working on a new site and working on getting two new Open Source projects final and out the door.

I’ve renamed Spigot to DataValve, and moved it to the new site FlutterCode.com which will also host my other project called Knappsack which is a set of Maven archetypes for Java EE 6.

The new site will be home to most of my tutorials, articles and other writings, as well as possibly some screencasts and even podcasts. It will in essence be a pure java development site. This blog will go a bit quieter and contain less development stuff, although most opinion will get put out here instead of over there. I’ll also be copying some of my tutorials over there from this blog.

I’m aiming to create a fairly cohesive tutorial site, aided in part by the Maven Archetypes which will give me a firm base onto which I can build tutorials without having to start from scratch, but one archetype is a sandbox Java EE 6 app with project configuration, a demo model and some test data. The sandbox app will let developers create a new skeleton java EE 6 application they can play with. Building on that, there is a sandbox-demo application which as an archetype that creates a full working demo CRUD application using Java EE 6 so developers can see how all the different pieces of Java EE 6 go together. It includes features such as conversations, JPA CRUD, page parameters, CDI injection and events.

Again, I have to say it, but Open Source is Hard. In the past couple of months, I have been working on a whole new site, getting 2 projects ready to roll with documentation and site content to boot as well as working a job, and having some kind of life.

Now it’s out, I can start to focus a little more on getting some more Java EE 6 tutorials and articles out.

Note : Spigot has been renamed to DataValve.

(Edit : I renamed this post so it doesn’t seem like Spigot is just for Seam, Spigot can be used with different frameworks or without any at all. However, I wrote this post since Spigot is so familiar to the Seam EntityQuery that it should be easy for Seam users to get the idea)

Seam developers should become familiar with Spigot concepts fairly quickly since they are very similar to those found in the Seam EntityQuery which was one of the main inspirations for the framework. If you imagine taking the entity query class and splitting it in two, one part to keep hold of state and the other to actually fetch the data. The stateful part is the Paginator that keeps track of what the current ordering of the data is, what is the current page and how big the pages are. The stateless part takes the Ejbql and the pagination information and returns a subset of the data. Now imaging that the data provider has the JPA pieces taken out and replaced with an abstract fetchResults method. This method is implemented in subclasses for specific data providers for text files, sql queries, jpa queries, native jpa queries, xml files, comma delimited or just an in memory dataset.
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Note : Spigot has been renamed to DataValve and is hosted over on FlutterCode.com.

It’s been a while since I’ve posted anything new as I’ve been busy with a new Open Source software project called Spigot. It’s a java library that sits between your application code and your data sources (Hibernate, JPA, JDBC or any arbitrary source of data) and helps with things like pagination and sorting using a common interface so you can switch out data providers and use alternatives.

For query language data providers, Spigot also facilitates excluding restrictions from WHERE clauses when parameters are resolved to null. Parameters are handled using parameter resolvers so there is more than one way to parameterize the query including EL expressions, reflection or a value map on the data provider.

Spigot also provides a few other add-ins like converting any dataset into an in-memory dataset that can itself be paginated and sorted and shared across an application (such as commonly used data in a web application). The IndexedDataProviderCache can give you random access into a dataset with caching and look ahead loading. This lets you hook a dataset with thousands of rows up to a Swing JTable with an instant response and a very small memory footprint since it doesn’t need to load all the objects at once as the provider will load the records as needed and cache the results. This is demonstrated in the Swing Demo in the download. There are also demos for Wicket and CDI with JSF.

You can ready about why I created Spigot in the documentation

Spigot is currently hosted on Project Kenai, where you can download the release, view documentation online or read about 10 ways Spigot helps developers.

Using composition over inheritance is a common design pattern that is often discussed in terms of designing business logic components. However, composition can solve a number of problems in domain object modeling that are created by relying on inheritance to share interface or functionality. Composition is used to delegate implementation in logical units by enlisting the help of a reference to an object that implements the required functionality instead of inheriting from it. This reference can be changed to different implementations depending on the needs at the time making for a more flexible design. This same design can be used in domain modeling to overcome some of the problems caused by inheritance. The typical flawed example of using inheritance in object modeling is the Person class which is often subclassed into Employee, User , Customer and Vendor classes.
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Like Christmas come early, Sun announced the release of JEE 6. This release sees continued improvement in the JEE stack with the inclusion of JSR 299, Java Contexts and Dependency Injection (CDI), and EJB 3.1 as well as JSF 2.0, and JPA 2.0. JSF especially has seen changes as a result of practical user feedback and community add-ons such as Seam and JSF Ajax frameworks which have contributed back to the JCP.

Glassfish v3 which implements the full JEE 6 stack has also been released, with JBoss’ Weld as the CDI implementation. Netbeans 6.8 has also been released with full JEE 6 project support including maven support for enterprise applications. Also of note is the hot deploy function of Glassfish which can deploy your app while maintaining session information.

Personally, I’m pleased. JEE 6 has really improved things for the java standards, and CDI has filled some gaps that previously required different additional pieces to completely fill. The ghosts of EJB 2.1 should now be permanently laid to rest, but should serve as a stark reminder. Having good frameworks to build standards based solutions is always good for the community.

I’ll try and get some tutorials on developing with CDI and JSF 2.0 with Netbeans and Glassfish out soon.

I’ve spent some time in the last couple of weeks playing around with Glassfish, Netbeans 6.8 Beta (and milestone 2 before it) and JSF 2.0, and I have to say that this is turning out to be a really good set of development libraries and tools.
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Here’s a couple of links regarding building Multi Module Apps with the Hibernate JPA Implementation. It was a subject I was starting to look at and these two articles just happened to cover both areas that I was interested in. Thought I’d share them and if nothing else, I know where to find them the next time I need them.

One of the problems faced by Seam users is the disconnect between the session scoped entity instances and using them in more local scopes. A good example is a session scoped User instance that is loaded when the user logs in and is outjected into the session scope. This user instance is available for the duration of the users session.
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