random

Processor

/**
 * Generate a random string, which is guaranteed to be a valid Java
 * identifier (first character is an ASCII letter, subsequent characters are
 * ASCII letters or numbers). Takes an optional parameter for the length of
 * string to generate; default is 8 characters.
 */
public String _random(String[] args) {
	int numchars = 8;
	if (args.length > 1) {
		try {
			numchars = Integer.parseInt(args[1]);
		}
		catch (NumberFormatException e) {
			throw new IllegalArgumentException("Invalid character count parameter in ${random} macro.");
		}
	}

	synchronized (Processor.class) {
		if (random == null)
			random = new Random();
	}

	char[] letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ".toCharArray();
	char[] alphanums = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789".toCharArray();

	char[] array = new char[numchars];
	for (int i = 0; i < numchars; i++) {
		char c;
		if (i == 0)
			c = letters[random.nextInt(letters.length)];
		else
			c = alphanums[random.nextInt(alphanums.length)];
		array[i] = c;
	}

	return new String(array);
}