The mediator validates the result of the evaluation of the source xpath expression, against the schema specified. If the source attribute is not specified, the validation is performed against the first child of the SOAP body of the current message. If the validation fails, the on-fail sequence of mediators is executed. Properties could be used to turn on/off some of the underlying features of the validator (See http://xerces.apache.org/xerces2-j/features.html)
Schema location
XPath expression to extract the XML that need to be validated. If not specified validation is performed against the first child of the SOAP body
Various features of the validator, http://xerces.apache.org/xerces2-j/features.html