A while ago, I wrote a post about using LINQ in C# to generate a random confirmation number.  On my current gig we are using Groovy to write test scripts for SOAP UI acceptance test cases (incidentally, SOAP UI is a great web service testing tool that probably deserves its own blog post). 

In order to generate a dummy random string, I used an algorithm similar to the one I used in the LINQ post and wanted to show how it would be implemented in Groovy.

// create the list of available characters
def availChars = []
('A'..'Z').each { availChars << it.toString() }
// even it out to about the same odds of getting a char or a number
3.times { (0..9).each { availChars << it.toString() } }

def generateRandomString = { length -> 
  def max = availChars.size    
  def rnd = new Random()
  def sb = new StringBuilder()
  length.times { sb.append(availChars[rnd.nextInt(max)]) }
  sb.toString()
} 

// print it out 10 times to see the randomness
10.times { println generateRandomString(8) }

If you're not familiar with Groovy, the -> symbol in the generateRandomString declaration marks a closure that takes one argument. In this case, it takes the desired length of the returned string. The last line invokes the closure n times. I really like (similar to Ruby) how you can pass function blocks as iterators over collections.  It makes creating a loop both simple and intuitive (e.g. 10.times).  And the syntantical sugar of creating a ranged list (e.g. 'A'..'Z') is another nice feature of the language.

Monday, July 14, 2008 2:21:50 PM (Eastern Standard Time, UTC-05:00)      Comments [0]  Groovy