I’m working on a jBPM prototype since last couple of days. The integration with Spring wasn’t a smooth ride. In my previous projects, I used jBPM3.2. But it seems jBPM4 is pretty much a rewrite. There are couple of few nice additions like service API’ for task and process management, support for java task and many more. And there are few changes which I didn’t like. Till 4.2 the support for JPA was provided, which is taken off starting 4.3 release. Yes definitely you can write some wrappers and still achieve it. But!! Between 4.3 and 4.4 also there are some major API changes. So the whole point is to get the app running, I had to digg into mailing lists and source code. Now that it works, I thought I would write a short blog about it.
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I decided to learn Scala when I saw a piece of code written by one of my colleagues. I was amazed with its conciseness. But I failed at my first attempt to learn this language. I know the reason why. I read some stuff without writing enough code. After couple of days, all the syntax was washed out of my head. You have to train yourself to forget some Java syntax for time being while you are writing Scala code and train your fingers with the new syntax. Don’t get drunk with Scala, Drink it slowly!! Don’t expect that after reading a book you would be fully functional to write Scala code for production. If you don’t find these difficulties while learning Scala, you must be a Geek!! I envy you!! But I’m sorry, the following blog post is not for you.
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Enterprise Search is becoming one of the common requirements of any consumer web application that we build these days. So I thought of learning some stuff in this domain. If you think about open source frameworks providing enterprise search functionality, probably Lucene is the one and only answer that comes to your mind. Lucene is a fully featured full text search engine library. Some other platforms and frameworks are developed that leverages core search functionality of Lucene.
Solr is one of such platforms that provide cool features like token highlighting, faceted search and many many more. Solr runs as a standalone search server and can be integrated into the applications using HTTP/XML API. Solr is typically used (or suggested to be used) when the underlying data that you are trying to index doesn’t change often.
Hibernate Search is a framework built on top of Lucene and Hibernate Core. In the following blog post, I would explain how to integrate Hibernate Search into your application.
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Recently I was playing around with Spring Integration. To understand any new framework one cannot just rely on documentation. So I created a demo application to try out different features of the framework. Since my main motivation was to understand Spring Integration framework, I wanted to spend minimal efforts in input data generation. So I decided to work with Twitter messages.
Most of you must be familiar with Twitter. Twitter is a service for friends, family, and co–workers to communicate and stay connected through the exchange of quick, frequent messages. There are different clients available to use Twitter. In the sample application, I first read the friends timeline. Then based on the source/client used for tweeting, the tweets are routed to different channels. The tweets originated from “web” are simply logged, while the tweets originated from “Dzone.com” are dispatched using a mail sender. The basic flow of the application is depicted in the following diagram.
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For the past few years of my career I worked mainly on designing and developing J2SE and J2EE enabled enterprise batch solutions and spent some time on database scripting and performance tuning. These years were spent on developing more enterprisy stuff.
The year 2009 was a year of whole and sole open source technologies. It was more about Web Technologies. I did some projects using Flex and Apache Wicket following Scrum methodology. I played around with open source CMS solutions like Magnolia and even Drupal (crazy it may sound but it works)!! As far as knowledge sharing is concerned, I did a tech talk on Esper – CEP Engine and imparted a training on Advanced RDBMS techniques. Also, I did some PoC’ on different libraries. Apart from this I got an opportunity to work with co-developers of Spring Framework and different open source projects at JTeam. All in all it was a good year of learning though not the best.
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Recently I presented a talk about Esper at JTeam Tech Meeting. Please go through the slides if you are interested in understanding more about Complex Event Processing and Esper . The first half of the presentation covers conceptual knowledge of Complex Event Processing, its advantages over traditional approaches and use cases. The second part covers API details of Esper – The Open Source CEP Engine written in Java.
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iText is a library that allows you to generate PDF files on the fly.
In the following blog post I would show how to
1. Create PDF using PDF Template and PDF Form
2. Appending documents
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