public class GUIDFactory {

	private static String hexCharacters = "0123456789abcdef";

	/**
	 * Generates a random GUID (hex) based on the following format :
	 *
	 * <pre>
	 * nnnnnnnn-nnnn-nnnn-nnnnnnnnnnnnnnnnn
	 * </pre>
	 *
	 * Example :
	 *
	 * <pre>
	 * 13219ec0-3a81-44c5-a300-de14b7d0235f
	 * </pre>
	 *
	 * @return A global unique identifier as a String
	 */
	public static String makeGUID() {

		String newGUID = "";
		int cmp = 0;

		for (int i = 0; i < 16; i++) {

			if (i == 4 || i == 6 || i == 8 || i == 10)
				newGUID += '-';

			cmp = (int) (Math.round(Math.random() * 255) - 128) & 255;

			if (i == 6) {
				cmp = cmp & 15;
				cmp = cmp | (4 << 4);
			}

			if (i == 8) {
				cmp = cmp & 63;
				cmp = cmp | 128;
			}

			newGUID += hexCharacters.charAt(cmp >> 4);
			newGUID += hexCharacters.charAt(cmp & 15);
		}

		return newGUID;
	}

}