Example usage for java.util Random nextInt

Introduction

In this page you can find the example usage for java.util Random nextInt.

Prototype

public int nextInt(int bound) 

Source Link

Document

Returns a pseudorandom, uniformly distributed int value between 0 (inclusive) and the specified value (exclusive), drawn from this random number generator's sequence.

Usage

From source file:com.microsoft.windowsazure.mobileservices.zumoe2etestapp.framework.Util.java

public static String createSimpleRandomString(Random rndGen, int size, int minChar, int maxChar) {
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < size; i++) {

        int charRand;
        char c;//w  ww .j av  a 2  s.com
        do {
            charRand = rndGen.nextInt(maxChar - minChar);
            c = (char) (minChar + charRand);
        } while (Character.isLowSurrogate(c) || Character.isHighSurrogate(c));

        sb.append(c);
    }

    return sb.toString();
}

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From source file:Main.java

/**
 * Fills the array with random doubles.  Values will be between min (inclusive) and
 * max (inclusive)./*from w  w  w.j a v  a 2  s .  c  o m*/
 */
public static void genRandomDoubles(long seed, double min, double max, double array[],
        boolean includeExtremes) {
    Random r = new Random(seed);
    int minExponent = Math.min(Math.getExponent(min), 0);
    int maxExponent = Math.max(Math.getExponent(max), 0);
    if (minExponent < -6 || maxExponent > 6) {
        // Use an exponential distribution
        int exponentDiff = maxExponent - minExponent;
        for (int i = 0; i < array.length; i++) {
            double mantissa = r.nextDouble();
            int exponent = minExponent + r.nextInt(maxExponent - minExponent);
            int sign = (min >= 0) ? 1 : 1 - r.nextInt(2) * 2; // -1 or 1
            double rand = sign * mantissa * Math.pow(2.0, exponent);
            if (rand < min || rand > max) {
                continue;
            }
            array[i] = rand;
        }
    } else {
        // Use a linear distribution
        for (int i = 0; i < array.length; i++) {
            double rand = r.nextDouble();
            array[i] = min + rand * (max - min);
        }
    }
    // Seed a few special numbers we want to be sure to test.
    for (int i = 0; i < sInterestingDoubles.length; i++) {
        double d = sInterestingDoubles[i];
        if (min <= d && d <= max) {
            array[r.nextInt(array.length)] = d;
        }
    }
    array[r.nextInt(array.length)] = min;
    array[r.nextInt(array.length)] = max;
    if (includeExtremes) {
        array[r.nextInt(array.length)] = Double.NaN;
        array[r.nextInt(array.length)] = Double.POSITIVE_INFINITY;
        array[r.nextInt(array.length)] = Double.NEGATIVE_INFINITY;
        array[r.nextInt(array.length)] = Double.MIN_VALUE;
        array[r.nextInt(array.length)] = Double.MIN_NORMAL;
        array[r.nextInt(array.length)] = Double.MAX_VALUE;
        array[r.nextInt(array.length)] = -Double.MIN_VALUE;
        array[r.nextInt(array.length)] = -Double.MIN_NORMAL;
        array[r.nextInt(array.length)] = -Double.MAX_VALUE;
    }
}

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From source file:dremel.common.AvroTest.java

private static Utf8 generateRandomUtf8(Random rand, int maxLength) {
    Utf8 utf8 = new Utf8().setLength(rand.nextInt(maxLength));
    for (int i = 0; i < utf8.getLength(); i++) {
        utf8.getBytes()[i] = (byte) ('a' + rand.nextInt('z' - 'a'));
    }//from w  w w  .j  av a  2  s.  co m
    return utf8;
}

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From source file:org.hdiv.util.HDIVUtil.java

/**
 * Generates a random number between 0 (inclusive) and n (exclusive).
 * //  w  w  w  .  j  a  va  2s . c  om
 * @param n
 *            the bound on the random number to be returned. Must be positive.
 * @return Returns a pseudorandom, uniformly distributed int value between 0 (inclusive) and <code>n</code>
 *         (exclusive).
 * @since HDIV 1.1
 */
public static String createRandomToken(int n) {

    Random r = new Random();
    int i = r.nextInt(n);
    if (i == 0) {
        i = 1;
    }

    return String.valueOf(i);
}

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From source file:Main.java

/**
 * This method generates a random n digit password, which contains at least one number, lower case alphabet, upper
 * case alphabet and as special character.
 *///from   ww w .  jav a 2s .  c  om
public static String generatePassword(int n) {

    Random rd = new Random();

    char lowerChars[] = "abcdefghijklmnopqrstuvwxyz".toCharArray();
    char upperChars[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ".toCharArray();
    char numbers[] = "0123456789".toCharArray();
    char specialChars[] = "~!@#$%^&*()-_=+[{]}|;:<>/?".toCharArray();

    List<Character> pwdLst = new ArrayList<Character>();
    for (int g = 0; g < 4; g++) {
        for (int z = 0; z < 1; z++) {
            if (g == 0) {
                pwdLst.add(numbers[rd.nextInt(10)]);
            } else if (g == 1) {
                pwdLst.add(lowerChars[rd.nextInt(26)]);
            } else if (g == 2) {
                pwdLst.add(upperChars[rd.nextInt(26)]);
            } else if (g == 3) {
                pwdLst.add(specialChars[rd.nextInt(26)]);
            }
        }
        if (pwdLst.size() == n) {
            break;
        }
        if (g + 1 == 4) {
            g = (int) Math.random() * 5;

        }
    }
    StringBuilder password = new StringBuilder();
    Collections.shuffle(pwdLst);
    for (int c = 0; c < pwdLst.size(); c++) {
        password.append(pwdLst.get(c));
    }
    return password.toString();
}

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From source file:com.nearinfinity.mele.MeleBase.java

private static File getNewLocalPath(List<String> pathList, String directoryCluster, String directoryName,
        Random random) {
    Collection<String> attempts = new HashSet<String>();
    while (true) {
        if (attempts.size() == pathList.size()) {
            throw new RuntimeException("no local writable dirs");
        }//from  www. j  ava 2s  .  co m
        int index = random.nextInt(pathList.size());
        String pathname = pathList.get(index);
        attempts.add(pathname);
        File file = new File(pathname);
        file.mkdirs();
        File testFile = new File(file, UUID.randomUUID().toString());
        try {
            if (testFile.createNewFile()) {
                testFile.delete();
                File dirFile = new File(new File(file, directoryCluster), directoryName);
                dirFile.mkdirs();
                return dirFile;
            }
        } catch (IOException e) {
            LOG.error("Can not create file on [" + file.getAbsolutePath() + "]");
        }
    }
}

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From source file:com.idrene.emefana.repositories.RepositoriesTest.java

public static int randInt(int min, int max) {

    // NOTE: Usually this should be a field rather than a method
    // variable so that it is not re-seeded every call.
    Random rand = new Random();

    // nextInt is normally exclusive of the top value,
    // so add 1 to make it inclusive
    int randomNum = rand.nextInt((max - min) + 1) + min;

    return randomNum;
}

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From source file:fr.cph.chicago.util.Util.java

public static int getRandomColor() {
    final Random random = new Random();
    final List<TrainLine> keys = Collections.unmodifiableList(Arrays.asList(TrainLine.values()));
    return keys.get(random.nextInt(keys.size())).getColor();
}

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From source file:de.uniwue.info6.misc.StringTools.java

/**
 *
 *
 * @param original//  w  ww.  j a v a 2 s.c  o m
 * @return
 */
public static String forgetOneWord(final String original) {
    final String[] originalParts = original.split("\\s");
    final Random random = new Random();
    final String originalPart = originalParts[random.nextInt(originalParts.length - 1)];
    final int index = original.indexOf(originalPart);
    return original.substring(0, index) + original.substring(index + originalPart.length(), original.length());
}

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From source file:com.xidu.framework.common.util.Utils.java

public static String randomString(int length) {
    Random randGen = null;
    char[] numbersAndLetters = null;
    char[] randBuffer = new char[length];
    randGen = new Random();
    numbersAndLetters = ("abcdefghijklmnopqrstuvwxyz").toCharArray();
    int i = 0;//  www .  jav a2 s . co m
    for (i = 0; i < randBuffer.length; i++) {
        randBuffer[i] = numbersAndLetters[randGen.nextInt(26)];
    }
    return new String(randBuffer);
}

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