com.facebook.presto.hive.$internal.jodd.util.RandomStringUtil Maven / Gradle / Ivy
// Copyright (c) 2003-2014, Jodd Team (com.facebook.presto.hive.$internal.jodd.org). All Rights Reserved.
package com.facebook.presto.hive.$internal.jodd.util;
import java.util.Random;
/**
* Generates random strings.
*/
public class RandomStringUtil {
protected static final Random rnd = new Random();
// ---------------------------------------------------------------- string
/**
* Creates random string whose length is the number of characters specified.
* Characters are chosen from the set of characters specified.
*/
public static String random(int count, char[] chars) {
if (count == 0) {
return StringPool.EMPTY;
}
char[] result = new char[count];
while (count-- > 0) {
result[count] = chars[rnd.nextInt(chars.length)];
}
return new String(result);
}
/**
* Creates random string whose length is the number of characters specified.
* Characters are chosen from the set of characters specified.
*/
public static String random(int count, String chars) {
return random(count, chars.toCharArray());
}
// ---------------------------------------------------------------- range
/**
* Creates random string whose length is the number of characters specified.
* Characters are chosen from the provided range.
*/
public static String random(int count, char start, char end) {
if (count == 0) {
return StringPool.EMPTY;
}
char[] result = new char[count];
int len = end - start + 1;
while (count-- > 0) {
result[count] = (char) (rnd.nextInt(len) + start);
}
return new String(result);
}
/**
* Creates random string whose length is the number of characters specified.
* Characters are chosen from the set of characters whose
* ASCII value is between 32 and 126 (inclusive).
*/
public static String randomAscii(int count) {
return random(count, (char)32, (char)126);
}
/**
* Creates random string that consist only of numbers.
*/
public static String randomNumeric(int count) {
return random(count, '0', '9');
}
/**
* Creates random string whose length is the number of characters specified.
* Characters are chosen from the multiple sets defined by range pairs.
* All ranges must be in acceding order.
*/
public static String randomRanges(int count, char... ranges) {
if (count == 0) {
return StringPool.EMPTY;
}
int i = 0;
int len = 0;
int lens[] = new int[ranges.length];
while (i < ranges.length) {
int gap = ranges[i + 1] - ranges[i] + 1;
len += gap;
lens[i] = len;
i += 2;
}
char[] result = new char[count];
while (count-- > 0) {
char c = 0;
int r = rnd.nextInt(len);
for (i = 0; i < ranges.length; i += 2) {
if (r < lens[i]) {
r += ranges[i];
if (i != 0) {
r -= lens[i - 2];
}
c = (char) r;
break;
}
}
result[count] = c;
}
return new String(result);
}
protected static final char[] ALPHA_RANGE = new char[] {'A', 'Z', 'a', 'z'};
protected static final char[] ALPHA_NUMERIC_RANGE = new char[] {'0', '9', 'A', 'Z', 'a', 'z'};
/**
* Creates random string of characters.
*/
public static String randomAlpha(int count) {
return randomRanges(count, ALPHA_RANGE);
}
/**
* Creates random string of characters and digits.
*/
public static String randomAlphaNumeric(int count) {
return randomRanges(count, ALPHA_NUMERIC_RANGE);
}
}