private void calculateHash() {
String string = rawInvoiceNumber + ';' + rawInvoiceDate + ';' + rawPriceExclVAT + ';' + rawLowVAT + ';' + rawHighVAT + ';' + rawPriceInclVAT + ';' + rawPaymentDiscount;
try {
try {
hash = Utils.toHex(MessageDigest.getInstance("MD5").digest(string.getBytes("UTF-8")));
} catch (UnsupportedEncodingException ex) {
Logger.getLogger(UnfinishedInvoice.class.getName()).log(Level.SEVERE, null, ex);