Testing variable by given rules

Question

Need to write a quick method static boolean varTest(String id) that tests of the input is indeed a variable based on the following rules:

variable ::= a dollar sign ($) followed by an integer, or any identifier starting with a letter followed by a mix of letters or digits.

Where for example both x$ or $x can be var's without this test.

So if not true, I want to throw ArithmeticException

SLaks · Accepted Answer · 2010-11-11 01:32:06Z

3

You're looking for a regular expression: $(\$[0-9]+)|([a-zA-Z][a-zA-Z0-9]*)^.

For example:

static Pattern p = Pattern.compile("$(\\$[0-9]+)|([a-zA-Z][a-zA-Z0-9]*)^");
static boolean varTest(String id) {
    return p.matcher(id).matches();
}

answered Nov 11, 2010 at 1:32

SLaks

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2 Comments

.matches returns true/false I assume?

@John: Yes; it returns a boolean.