Tuesday, May 19, 2009

Pentaho Analysis Tool Integrated as a Pentaho Plugin

I had the chance this week to play around with the still-under-construction Pentaho plugin architecture in the Citrus code line. The new architecture is just what BI developers have been waiting for: totally flexible with several new ways to integrate with the server, simple to use and allows for building nicely decoupled extensions.

With Aaron Phillip's help, I got my head around the new features in less than a day, and had my first plugin written shortly after: The Pentaho Analysis Tool (PAT) plugin. Before I get into the details of the PAT plugin, let's first talk about the new tools and capabilities in the Pentaho BI server's plugin layer.

The plugin architecture consists of several different fun ways you can hook into the Pentaho BI Server, without having to modify server code or disturb the platform deployment. All avenues for leveraging the plugin architecture expect that the necessary files and code will be found in the solutions folders. The layer currently has the following capabilities:

  1. Customization of the menu system of the "classic" and more recent PUC (Pentaho User Console) user interfaces
  2. Customization of various page contents (overlays)
  3. New types of content to be added to the solution repository and operated upon in the user console
  4. New Java classes that generate UI pages to be dynamically added to the server
  5. (new in 3.0) Add your own BI Component to the platform without having to modify system files and paths
You can get more details about these features and how they work by reading the documentation here. Aaron also created a sample plugin that demonstrates each of these features in a simple plugin mockup, that also is a great template to use for new plugin creation.

So that's exactly what I did. Here's a screenshot of the results of my plugin:

Using the EchoPlugin sample as a guide, I created a new content type (.xpav, for Pentaho Analysis View) which is the first notion of a view definition file for PAT. When you "open" this new content type in PUC, it initializes and launches PAT, which is a separately deployed web application. This is accomplished by creating a new content generator in the plugin that delegates the generation to the PAT webapp. It takes a bit to put it all together: you need a bleeding edge Citrus BI Server download, the latest PAT code and the plugin project. If you are interested in seeing it in action, read the integration instructions here.

I only took advantage of a couple of the new plugin layer's capabilities in my first plugin. I'm looking forward to playing with the new web services as well as the component that allows my plain old Javabean to look like a BI component automagically. I can foresee great extensions coming fast for the Pentaho BI Server with this new architecture!

I've listed some good references for those who are ready to take a look at plugins:

Here is the documentation:

and here is the Plugin Depot, where you can show others the cool new extensions you've built:

and if you have questions, comments or problems, or think you may have spotted a bug, chat with some of the developers about it here:

kindest regards,

Sunday, May 10, 2009

Maven: The Definitive Guide

My one true nerdy tendency: I like writing technical documentation. It's ironic then (or a bit of a hypocrisy) that I loathe reading it. Chalk it up to my lack of passion for technology. I am a passionate problem solver; technology is a sometimes rewarding, sometimes frustrating means to help effectively get the problem solving job done.

Recently, I began reading Maven: The Definitive Guide while getting a pedicure at my local salon (laugh it up guys, I can guess where most of you do your leisure reading). I strongly recommend that any developer approaching Maven for the first (or tenth) time give chapters 3 through 8 a read. This guide is what you hope most technical guides or books would be, but then usually quite early on, they disappoint.

The guide starts with a quick, understandable introduction to Maven terminology and concepts, via a short step by step example. As I was reading this from a "make this worth my while" perspective, I had specific use case questions that immediately popped into my head ... and then, I was pleasantly surprised to find the answers in the next few paragraphs.

For example, the guide mentions early on that "support for transitive dependencies is one of Maven's most powerful features". To that my questions were "What about conflicts in dependency hierarchies?" and "What about compile time dependencies that I don't want to package?". The rest of the chapter addresses exactly those questions with explanations on dependency exclusions and scoping. Finally. A book that thinks like I do :)

A quick summary of the rest of the meat of the guide: chapters 4 through 8 build on the core concepts introduced in 3, with bite size chunks of additional functional explanation in each chapter. The material is presented as a hands on example, building in feature complexity little by little. Chapter 4 shows you how to add new dependencies to your project; 5 introduces simple web application features; chapters 6 and 7 cover multi-module project and enterprise project features. This presentation worked for me on a few different levels:

  1. The graduated approach to the introduction of new materials made a large amount of Maven terminology, concepts and finally usage documentation digestible.
  2. The authors take great care in describing WHY they arrange and refactor the projects as they do, in a very modular fashion. This approach, in practice, lends itself not only to Maven's default conventions, but also to best practices for software project layout. Note that this introduced complexity to the examples that wasn't necessary to explain the features at hand. But the authors bit that bullet in order to present a good and useful way of developing a project.
  3. The example projects described in the guide are immediately relevant for me. I write Java code. I use Spring. I use Hibernate. This, of course, will not be the case for every reader, but it was a nice bonus for me.
So after all of my monologue thoughts, I leave you with a few tids:

  • Read the guide (at least Part 1), then decide how problematic you perceive Maven to be. I know my perception changed dramatically.
  • Note that it is a bit outdated, deprecated goals and such (the guide is updated for Maven 2.0.10, I downloaded Maven 2.1). This really didn't distract me at all.
  • The chapters I reference are only the tip of the iceberg. Part 2 of the guide includes another 200 reference pages that I have yet to use. I'll let you know how that goes for me:)