Logic Sentences in XMl files

[Govan Marounsi <govan@kth.se>]

I am going to work with some XML files containing logic sentences like these:

<condition>
     <or>
        <not>
           <eq>
               <variable>
                   <name>X</name>
                   <variabletype>Test</variabletype>
                   <datatype>String</datatype>
                </variable>
                <constant>
                   <value>finished</value>
                   <datatype>String</datatype>
                 </constant>
            <eq>
         </not>
         <gt>
           <variable>
                <name>X</name>
                <variabletype>Result</variabletype>
                <datatype>int</datatype>
           </variable>
           <constant>
                <value>50</value>
                <datatype>int</datatype>
           </constant>
         </gt> 
   </or>
</condition>

My questions:
1- Is there any standard XML schema for displaying logic sentences in XML files? I am looking for something like RFC (Request for comments).

2- What is the best way to translate and evaluate these sentences in XML files with help of Java?

3- I want to write code for auto generating a GUI which with help of it users can change the value of variables in logic sentences? Is there any special technique to generate GUI (Swing or Jface) from XML files?

Appreciating your advise and help
//Govan