The Essential Drools Cheat Sheet at DZone is out!

Hi! I'm pleased to announce that Maro Fusco's and mine DZone Refcard - The Essential Drools Cheat Sheet is out at http://refcardz.dzone.com/refcardz/drools. Hope you enjoy it :)

Mockito - Extra Interfaces with annotations and static methods

In the code I have quite recently came across a really bad piece of code that based on class casting in terms of performing some actions on objects. Of course the code needed to be refactored but sometimes you can't do it / or don't want to do it (and it should be understandable) if first you don't have unit tests of that functionality. In the following post I will show how to test such code, how to refactor it and in fact what I think about such code ;)

Mockito - RETURNS_DEEP_STUBS for JAXB

Sorry for not having written for some time but I was busy with writing the JBoss Drools Refcard for DZone and I am in the middle of writing a book about Mockito so I don't have too much time left for blogging...

Anyway quite recently on my current project I had an interesting situation regarding unit testing with Mockito and JAXB structures. We have very deeply nested JAXB structures generated from schemas that are provided for us which means that we can't change it in anyway.

Execution of Groovy scripts from Java - XmlSlurper and MarkupBuilder in mapping issues

Problem with mappings

In our project we came across a really big problem related to mapping. Having two systems that initially were defined by the BA to be somehwat simillar we have chosen the simple XSLT (done through Altova Mapforce) of the input message to the output one.

Afterwards it turned out that the functions required to perform a mapping are becoming enormous. An example of such a mapping is:

From the input message take a list of Cars iterate over it and find a Car whose field "prodcutionDate" is the lowest and the attribute "make" is equal to "Honda" and as the output return the "saleDate"

So in order to map it we decided to move to JBoss Drools. The decision tables were out of question since the logic was to complex and customized to be placed in the spreadsheet so we coded everything in the DRL files. Soon the rules got really big and some of our developers were forced to spend plenty of time on constant recreation of rules stated by the BA.

Out of frustration and after having seen all the amazing things at the 33rd degree conference I decided to start finding solutions to my problems which were:

Drools decision tables with Camel and Spring

Hi!

As I've shown it in my previous post JBoss Drools are a very useful rules engine. The only problem is that creating the rules in the Rule language might be pretty complicated for a non-technical person. That's why one can provide an easy way for creating business rules - decision tables created in a spreadsheet!

In the following example I will show you a really complicated business rule example converted to a decision table in a spreadsheet. As a backend we will have Drools, Camel and Spring.

Concurrency in web applications

Nice article about concurrency in web applications (in Polish)

Drools - Rete Alogrithm explanation

Quite recently I have found a very nice article about the Rete Algorithm.