Created
November 10, 2017 14:21
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User friendly random code generator
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import java.security.SecureRandom; | |
import java.util.Random; | |
public class RandomCodeGenerator { | |
static final SecureRandom RANDOM = new SecureRandom(); | |
static final char[] LETTERS = "ABCEFGHJKMNPQRSTWXYZ".toCharArray(); | |
static final char[] NUMBERS = "0123456789".toCharArray(); | |
static final int DEFAULT_NUM_CODES = 20; | |
public static void main(String[] args) { | |
int numCodes = DEFAULT_NUM_CODES; | |
if (args.length >= 1) { | |
numCodes = Integer.parseInt(args[0]); | |
} | |
System.out.println("======================================================"); | |
System.out.println(""); | |
for (int i = 0; i < numCodes; i++) { | |
System.out.println(" " + randomCode(RANDOM)); | |
} | |
System.out.println(""); | |
System.out.println("======================================================"); | |
} | |
private static String randomCode(Random rng) { | |
StringBuilder sb = new StringBuilder(); | |
randomTriplet(rng, sb); | |
sb.append('-'); | |
randomTriplet(rng, sb); | |
sb.append('-'); | |
randomTriplet(rng, sb); | |
sb.append('-'); | |
randomTriplet(rng, sb); | |
return sb.toString(); | |
} | |
private static StringBuilder randomTriplet(Random rng, StringBuilder sb) { | |
return sb.append(randomChar(rng, NUMBERS)) | |
//.append(randomChar(rng, LETTERS)) | |
.append(randomChar(rng, NUMBERS)) | |
.append(randomChar(rng, NUMBERS)); | |
} | |
private static char randomChar(Random rng, char[] alphabet) { | |
return alphabet[rng.nextInt(alphabet.length)]; | |
} | |
} |
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