apply mathematical rules stored in database to a variable gotten from human machine interface

I'm developing a project with Flex, Spring, Hibernate, MySQL, Tomcat, but one of the functionality is: " i have to store开发者_运维问答 a mathematical rule like for example " a+b " into database, then in my human machine interface, i have two fields when user write the variables "a" and "b", then a button with the label calculate which if it's clicked, it'll show bellow the result of applying the rule " a+b " to the variables "a" and "b" which the user previously." Now, i'm searching for an Java or Flex API or any other way that will give me the ability to apply a mathematical rule stored in database as string, to variables i got from human machine interface"

If I understand the question correctly, you're just looking for JAXP, the Java API for XML Processing.

The Java API for XML Processing (JAXP) is for processing XML data using applications written in the Java programming language. JAXP leverages the parser standards Simple API for XML Parsing (SAX) and Document Object Model (DOM) so that you can choose to parse your data as a stream of events or to build an object representation of it.