code: public Object execute(final Object value, final CsvContext context) {
  		validateInputNotNull(value, context);
  		
  		int hash = value.hashCode();
  		if( !uniqueSet.add(hash) ) {
  			throw new SuperCsvConstraintViolationException(
  				String.format("duplicate value '%s' encountered with hashcode %d", value, hash), context, this);
  		}
  		
  		return next.execute(value, context);
  	}
docs: {@inheritDoc}
  
  @throws SuperCsvCellProcessorException
  if value is null
  @throws SuperCsvConstraintViolationException
  if a non-unique value is encountered