Example usage for java.util Random Random

Introduction

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

Prototype

public Random()

Source Link

Document

Creates a new random number generator.

Usage

From source file:Main.java

/**
 * Scramble oder of elements in a list.//from   w w w  .  j  a  v  a2s . c  om
 *
 * @param list
 */
public static <E> void scrambleList(List<E> list) {
    if (isNotEmpty(list)) {
        Random generator = new Random();
        for (int i = 0; i < list.size(); i++) {
            int random = generator.nextInt(list.size());
            if (random != i) {
                //Util of vs.(swap)
                E objTemp = list.get(i);
                list.set(i, list.get(random));
                list.set(random, objTemp);
            }
        }
    }
}

From source file:Main.java

public static void shuffle(final int[] array) {
    final Random r = new Random();
    final int limit = array.length;
    for (int i = 0; i < limit; ++i) {
        swap(array, i, r.nextInt(limit));
    }/*from www  .  j  a  v a  2s. c  o m*/
}

From source file:Test.java

private static void startUpdatingThread(final List<String> list) {
    updatingThread = new Thread(new Runnable() {
        long counter = 0;

        public void run() {
            while (!Thread.interrupted()) {
                int size = list.size();
                Random random = new Random();
                if (random.nextBoolean()) {
                    if (size > 1) {
                        list.remove(random.nextInt(size - 1));
                    }//from   www .  jav a  2s.  com
                } else {
                    if (size < 20) {
                        list.add("Random string " + counter);
                    }
                }
                counter++;
            }
        }

    });
    updatingThread.start();
}

From source file:Main.java

public static byte[][] splitUnicodeMessage(byte[] aMessage, Integer maximumMultipartMessageSegmentSize) {

    final byte UDHIE_HEADER_LENGTH = 0x05;
    final byte UDHIE_IDENTIFIER_SAR = 0x00;
    final byte UDHIE_SAR_LENGTH = 0x03;

    // determine how many messages have to be sent
    int numberOfSegments = aMessage.length / maximumMultipartMessageSegmentSize;
    int messageLength = aMessage.length;
    if (numberOfSegments > 255) {
        numberOfSegments = 255;/* w ww . j a v a  2  s . c  om*/
        messageLength = numberOfSegments * maximumMultipartMessageSegmentSize;
    }
    if ((messageLength % maximumMultipartMessageSegmentSize) > 0) {
        numberOfSegments++;
    }

    // prepare array for all of the msg segments
    byte[][] segments = new byte[numberOfSegments][];

    int lengthOfData;

    // generate new reference number
    byte[] referenceNumber = new byte[1];
    new Random().nextBytes(referenceNumber);

    // split the message adding required headers
    for (int i = 0; i < numberOfSegments; i++) {
        if (numberOfSegments - i == 1) {
            lengthOfData = messageLength - i * maximumMultipartMessageSegmentSize;
        } else {
            lengthOfData = maximumMultipartMessageSegmentSize;
        }

        // new array to store the header
        segments[i] = new byte[6 + lengthOfData];

        // UDH header
        // doesn't include itself, its header length
        segments[i][0] = UDHIE_HEADER_LENGTH;
        // SAR identifier
        segments[i][1] = UDHIE_IDENTIFIER_SAR;
        // SAR length
        segments[i][2] = UDHIE_SAR_LENGTH;
        // reference number (same for all messages)
        segments[i][3] = referenceNumber[0];
        // total number of segments
        segments[i][4] = (byte) numberOfSegments;
        // segment number
        segments[i][5] = (byte) (i + 1);

        // copy the data into the array
        System.arraycopy(aMessage, (i * maximumMultipartMessageSegmentSize), segments[i], 6, lengthOfData);

    }
    return segments;
}

From source file:lifetime.backend.util.TestHelper.java

/**
 * Returns a new random byte array.//from w w w .j  a v  a 2s. c o m
 *
 * @return A byte array.
 */
public static byte[] getRandomByteArray() {
    byte[] result = new byte[1024];
    new Random().nextBytes(result);
    return result;
}

From source file:Main.java

public static int getRandom(int min, int max) {
    if (min > max) {
        return 0;
    }/* w w w .j  ava 2 s  . co m*/
    if (min == max) {
        return min;
    }
    return min + new Random().nextInt(max - min);
}

From source file:fakedatamaker.util.RandomFileUtil.java

/**
 * //from w w  w. jav  a 2 s. c o  m
 * @param filePath
 * @param encoding
 * @return
 */
public static String getRandomFileLine(String filePath, String encoding) {
    String result = null;

    try {
        File file = new File(filePath);
        List<String> cityLines = FileUtils.readLines(file, encoding);
        int numberOfCities = cityLines.size();
        Random r = new Random();
        int cityLineNum = r.nextInt(numberOfCities);

        result = cityLines.get(cityLineNum);
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    return result;
}

From source file:Main.java

/**
 * Given a list, returns a random element from that list.
 *
 * @param list  The list to return a random element from
 *
 * @param <T>  The element type of the list
 *
 * @return A random element from the list
 *///from   w  w  w.  j av a2 s  . co m
public static <T> T getRandomElement(List<T> list) {
    return list.get(new Random().nextInt(list.size()));
}

From source file:Main.java

/** Returns temp dir, containing String arg in its name;
 *  does not create the directory. */
public static File getTempDir(String desc) {
    String tempDir = System.getProperty("java.io.tmpdir");
    if (tempDir == null)
        throw new RuntimeException("java.io.tmpdir undefined, cannot run test");
    return new File(tempDir, desc + "." + new Random().nextLong());
}

From source file:com.saax.gestorweb.util.DAOAleatorio.java

public static Departamento getDepartamentoAleatorio(EntityManager em, Empresa e) {
    List<Departamento> departamentos = em.createNamedQuery("Departamento.findByEmpresa")
            .setParameter("empresa", e).getResultList();
    return departamentos.get(new Random().nextInt(departamentos.size() - 1));
}