JPA


Conversational CRUD in Java EE 6

This tutorial will demonstrate a pattern for creating CRUD applications in JSF and Java EE 6. While this is not the only way of implementing this mechanism, it does promote re-use and can give you essentially zero code CRUD pages requiring just the view code. The goal is to provide a single structure that provides the particular feature of being both stateless or conversational where we might want a conversational edit page and a stateless view page. This pattern is based on the EntityHome pattern that was used in JBoss Seam and carries over well to Java EE 6 with CDI. This is something I use all the time to make view/edit pages really quickly and unlike most of the automatic scaffolding in other frameworks, doesn’t need re-writing to go into production.
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Demo Application Using JSF, JPA, CDI with Jetty

The previous version of the Knappsack Maven Archetypes included archetypes for creating projects using JSF, JPA, CDI and Bean Validation that can run in a servlet container such as Jetty or Tomcat. In order to put it through its paces I decided to create a little test social bookmarking application that lets users create accounts, and when logged in, add bookmarks and tag them. Users that are not logged in can view the bookmarks and filter them by user or tag, and the results are paginated.
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Try Java EE 6 without the commitment

The latest version of the Knappsack Maven Archetypes now supports creating Java EE 6 applications for servlet containers. These projects includes configuration for core Java EE 6 technologies such as JSF, CDI, JPA and Bean Validation and can be run from the command line using the embedded Jetty and Tomcat servlet containers.

Also with this latest release, all the archetypes are available in the Central Maven Repository which means you can dive straight in and create a new Maven project using these archetypes :
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Knappsack Archetypes are now in the Maven Central Repository

I have finally got around to putting the Mavan Java EE 6 Archetypes into the Maven Central Repository. This means you no longer have to manually download and install the Archetypes, they should be available for you to use out of the box. In some cases, depending on how you are creating your projects, you may need to refresh or update your Repository indexes in the IDE before they are visible.

In Eclipse (with m2Eclipse installed), you open the Maven Repositories view, locate the Central Repository in the global repositories, and right click and select update index to make the archetypes available.

To create a new project from the command line, you can copy the following command into a script or batch file and edit it to setup your own group and archetype values.

mvn archetype:generate -DarchetypeGroupId=org.fluttercode.knappsack -DarchetypeArtifactId=jee6-sandbox-demo-archetype -DinteractiveMode=false -DarchetypeVersion=1.0.4 -DgroupId=org.application -DartifactId=sandboxdemo -Dpackage=org.application

The new version includes the archetypes for creating Java EE 6 applications in servlet containers which lets you play around with CDI, JSF, JPA, validation and other JEE 6 technologies using an embedded servlet container from the command line.

Knappsack Archetypes Part 1

This set of articles will document the contents of the Java EE archetypes for Maven. The archetypes come in four flavors, basic,minimal, sandbox and sandbox demo with each one being based on the previous one. In part 1, we’ll give an overview of the archetypes and the structure and configuration used in all of the archetypes. Read More »

FlutterCode.com released

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.

A Guide to Spigot For Seam Developers

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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