nested struts2 validation

Hi, I would like to do nested struts2 validation. I have two questions. 1) How do I specify the validation for the following field. Can some point me to some documenation for the expression validation. searchResults.{#this.resource.name.length() > 0}.{? #this == false }.size() <= 0

nested struts2 validation

Hi, I would like to do nested struts2 validation. I have two questions. 1) How do I specify the validation for the following field. Can some point me to some documenation for the expression validation. searchResults.{#this.resource.name.length() > 0}.{? #this == false }.size() <= 0