What is faster, Regex or if compares - Java

Question

I have two possibilities, make a regex or make a if compare.

If Compares

if (!(modoImpressao.equals("IMPRESSORA") || 
   modoImpressao.equals("PDF") || modoImpressao.equals("AMBOS")))

Regex Match

if (!Pattern.compile("(IMPRESSORA)|(PDF)|(AMBOS)",Pattern.DOTALL).matcher(modoImpressao).find()){
            throw new EspdNeverStopParametroInvalidoException(TspdConstMessages.IMPRIMIR_PARAMETRO_MODOIMPRESSAO_INVALIDO,"TspdImprimirNFCe");
        }

which one is faster?

Answer 1

The first snippet will almost certainly be faster, since it doesn't have to parse a regular expression and perform a match against it. Another alternative is:

if (Arrays.asList("IMPRESSORA", "PDF", "AMBOS").contains(modoImpressao)

which shouldn't differ speed-wise much from your first snippet, but is arguably more readable and concise.

Regular expressions are great, but only use them when you need to. This situation definitely doesn't warrant the use of regexes; all you're doing is comparing against literal strings.

There's an old saying by Jamie Zawinski that goes like this:

Some people, when confronted with a problem, think "I know, I'll use regular expressions." Now they have two problems.