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// Copyright (c) 2003-present, Jodd Team (http://jodd.org)
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
package jodd.util;
import java.util.Random;
import java.util.concurrent.ThreadLocalRandom;
/**
* Class that generates random strings.
*/
public class RandomString {
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'};
protected final static RandomString INSTANCE = new RandomString();
/**
* Returns default instance of RandomString.
*/
public static RandomString get() {
return INSTANCE;
}
protected final Random rnd;
/**
* Creates new random string.
*/
public RandomString() {
this(ThreadLocalRandom.current());
}
/**
* Creates new random string with given random object,
* so random strings can be repeated.
*/
public RandomString(final Random rnd) {
this.rnd = rnd;
}
/**
* Creates new random string with given seed.
*/
public RandomString(final long seed) {
this.rnd = new Random(seed);
}
// ---------------------------------------------------------------- string
/**
* Creates random string whose length is the number of characters specified.
* Characters are chosen from the set of characters specified.
*/
public String random(int count, final 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 String random(final int count, final 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 String random(int count, final char start, final 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 String randomAscii(final int count) {
return random(count, (char) 32, (char) 126);
}
/**
* Creates random string that consist only of numbers.
*/
public String randomNumeric(final 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 String randomRanges(int count, final 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);
}
/**
* Creates random string of characters.
*/
public String randomAlpha(final int count) {
return randomRanges(count, ALPHA_RANGE);
}
/**
* Creates random string of characters and digits.
*/
public String randomAlphaNumeric(final int count) {
return randomRanges(count, ALPHA_NUMERIC_RANGE);
}
/**
* Creates random string that contains only Base64 characters.
*/
public String randomBase64(final int count) {
return random(count, Base64.CHARS);
}
}