private PropertyMapping populatePropertyMapping(ExtensionProperty ep){
  PropertyMapping pm=mapping.getField(ep.getQualname());
  if (pm == null) {
    pm=new PropertyMapping();
  }
  pm.setTerm(ep);
  return pm;
}

private PropertyMapping populatePropertyMapping ( ExtensionProperty ep ) { PropertyMapping pm = mapping . getField ( ep . getQualname ( ) ) ; if ( pm == null ) { pm = new PropertyMapping ( ) ; } pm . setTerm ( ep ) ; return pm ; }
populate a propertymapping from an extensionproperty . if the extensionproperty is already mapped , preserves the existing propertymapping . otherwise , creates a brand new propertymapping .
