[antlr-interest] how to check if a optional token exists or not ??

[OJAY78 at gmx.de]

Hi,

I stuck on a small Problem. I have this rule with an optional token meta. In the Java Code I want to check if this token is null or not so that I can call a other method. But this check of the meta token will result in a nullpointer exception. Does anyone know how I can solve this? How can I check the meta token?

Thanks

valueType returns[StringObject value]
	:'value' ',' rv=function_parameter (',' meta=valueMetaType)?
	{
	
	String valName = $rv.value;
	FormValue fv = formInstance.getFormValue( valName 
		
		if( fv == null ) {
			log.debug("VALUE TYPE: Feld ist leer");
			$value = new StringObject("",null,null);
		}
		else {
			if ($meta.text == null){
			$value = new StringObject(fv.getFieldValue().toString(),fv,valName);
			}
			else{
			 $value=FELHelper.getFormValueMeta(fv,$meta.text);
			}
		}

	}
	;
-- 
Psssst! Schon vom neuen GMX MultiMessenger gehört?
Der kann`s mit allen: http://www.gmx.net/de/go/multimessenger