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.

New Too Much Coding repository!

Hi!

As you know there is a code repository of Too Much Coding sources here at Bitbucket. If you don't like it you can also find the Too Much Coding sources at GitHub!

Enjoy :)

Drools integration with Spring vs manual rules creation

Hi!

 Often in your work you can come across with issues related to business logic. Let us assume that you have dozens of rules (for the time being in our project we have more than 50 and I used to work on a project where we had hundreds of those rules) that you have to implement, divide into some classes, subclasses, abstractions and of course unit test. This can be difficult and timeconsuming to both write and support. There are many ways of dealing with this problem and I will show you one of them - JBoss Drools.

Drools is a library specifically created for such purposes like implementing rules. As presented in Wikipedia:

"Drools is a rule engine implementaion based on Charles Forgy's Rete Algorithm tailored for the Java language." 

It contains a rule engine that can process rules wirtten using the Drools language (you can also provide rules in Excel spreadsheets! - perfect for Business side to support and maintain).

In the following example we will take a look at the way one can integrate JBoss Drools with Spring and an example of solving a similar problem without Drools.

Very interesting article about XSD

A friend from my project (that will soon start his own blog ;) here is his blog ) has found a very interesting article about XSDs and namespaces.

 Tutorial about XSD and namespaces