public String getFieldName ( ) { AlphaNodeFieldConstraint constraint = this . node . getConstraint ( ) ; if ( constraint instanceof MvelConstraint ) { MvelConstraint mvelConstraint = ( MvelConstraint ) constraint ; InternalReadAccessor accessor = mvelConstraint . getFieldExtractor ( ) ; if ( accessor instanceof ClassFieldReader ) { return ( ( ClassFieldReader ) accessor ) . getFieldName ( ) ; } } return null ; }
Constraint has field extractor and this method is returning fieldName it .