public String evaluate(MessageContext synCtx, String credentialElemName) {
String sourceObject = null;
// expression is required to perform the match
if (credentialTokensMap.containsKey(credentialElemName)) {
SynapseXPath xpath = credentialTokensMap.get(credentialElemName);
sourceObject = xpath.stringValueOf(synCtx);
if (null == sourceObject) {
log.debug(String.format("Source String : %s evaluates to null",
xpath.toString()));
}
} else if (credentialTokenValueMap.containsKey(credentialElemName)) {