Thanks for the detailed explanation Anil! I agree that Drools might be an overkill for this requirement. I am looking at Groovy and shall take a look at Rhino as well.
Thanks, Yogesh ________________________________ From: Anil Gangolli <a...@busybuddha.org> To: users@appfuse.dev.java.net Sent: Friday, February 13, 2009 11:03:57 AM Subject: Re: [appfuse-user] Mathematical formula implementation in Java/JEE We recently used Javascript (using Rhino) for something that sounds similar. In Java 1.6, there is a generic scripting API with Rhino shipped with the SDK. We were unable to use Java 1.6 yet at build time for compatibility reasons but we are essentially using the same combination. Groovy would probably be a good choice as well. Drools would be more appropriate if you need to worry about complex rule chaining. We handled simple acyclic recomputation chaining ourselves by explicitly tracking dependencies and changes in result values. (e.g. x depends on y and z, y depends on a and b. The value of b changes, y requires recomputation, x requires recomputation). --a. tonylu880042 wrote: Hi, I would like suggest you to use the GroovyShell from Groovy project. I use this in my web action for providing some rule customization just like your case. The advantage of using GroovyShell() is you can put your Java data model into GroovyShell and execute your script(Mathematical formula which is coded in Java form). Or, you can using the dynamic bean in Spring for further detail please check out my blog in the following link. http://tony880042.blogspot.com/2008/08/how-to-add-scripting-support-in-your.html http://tony880042.blogspot.com/2008/08/how-to-add-scripting-support-in-your.html Yogesh Bhardwaj wrote: Hello all, This question is not related to AppFuse so please pardon me, but since there are so many developers from open source community here, just thought of getting some opinions. We have a business requirement in which the end users would create mathematical "formulae" through a UI. So in a single transaction, a user could create a formula, apply it on the transactional data, and save the formula for future use. The operands in a formula would be attributes of certain objects, and the operators could potentially go beyond just simple algebraic operators. An example could look like this: if (object.country == "USA") then output = (object.normalRate * (@someConstant + #someUserInput)) / object.quantity else output = (object.exciseRate * @someConstant) / object.quantity The "decision-making" behavior of the formula inclines me towards using some rules engine like JBoss Rules/Drools. Does anyone here know if JBoss Rules or any other rules engine would fit for a requirement like this, where rules could be created dynamically through a UI and then saved (file or database) or users could select a rule among several available ones? I would really appreciate any feedback. Thanks, Yogesh
