Struts 2 when one or two sets of fields are required

[Katie Doody]

I am working on validation and need to do the following logic:

 <validator type="expression">
        <param name="expression"><![CDATA[((lawPermEasement != null && permAcres != null) || (lawTempEasement  != null && tempAcres != null ))]]></param>
        <message key="Easement_MissingAcres"/>
    </validator>   

What I am trying to do is say either lawPermEasement and permAcres must have values OR lawTempEasement and tempAcres must have values OR all four fields can have values.

I am having real problems with whether the validation should be written in the negative or the positive.
[ September 17, 2008: Message edited by: Katie Doody ]

[Katie Doody]

I found the answer to my question. My syntax was wrong. This accomplishes what I need to do;

<validator type="expression">
      <param name="expression">!((tempAcres == "" and permAcres == "") or (lawPermEasement == "" and lawTempEasement == "") or (tempAcres != "" and lawTempEasement == "") or (tempAcres == "" and lawTempEasement != "") or (permAcres != "" and lawPermEasement == "") or (permAcres == "" and lawPermEasement != "")) </param> 
        <message key="Easement_MissingAcres"/>
  </validator>

[ September 23, 2008: Message edited by: Katie Doody ]