docs: public Object execute(final Object value, final CsvContext context) {
  		if (value == null){
  			throw new SuperCsvConstraintViolationException("the String should not be null", context, this);
  		}
  		
  		if( value instanceof String ) {
  			final String stringValue = (String) value;
  			if( stringValue.length() == 0 ) {
  				throw new SuperCsvConstraintViolationException("the String should not be empty", context, this);
  			}
  		} else {
  			throw new SuperCsvCellProcessorException(String.class, value, context, this);
  		}
  		
  		return next.execute(value, context);
  	}