public void addField ( FormField field ) { String fieldVariableName = field . getVariable ( ) ; // Form field values must be unique unless they are of type 'fixed', in // which case their variable name may be 'null', and therefore could // appear multiple times within the same form. if ( fieldVariableName != null && hasField ( fieldVariableName ) ) { throw new IllegalArgumentException ( "This data form already contains a form field with the variable name '" + fieldVariableName + "'" ) ; } synchronized ( fields ) { fields . put ( fieldVariableName , field ) ; } }
Adds a new field as part of the form .