Groovy: Generate random string from given character set

Question

Using Groovy, I\'d like to generate a random sequence of characters from a given regular expression.

• Allowed charaters are: [A-Z0-9]
• Length o

Answer 1

If you don't want to use apache commons, or aren't using Grails, an alternative is:

def generator = { String alphabet, int n ->
  new Random().with {
    (1..n).collect { alphabet[ nextInt( alphabet.length() ) ] }.join()
  }
}

generator( (('A'..'Z')+('0'..'9')).join(), 9 )

but again, you'll need to make your alphabet yourself... I don't know of anything which can parse a regular expression and extract out an alphabet of passing characters...