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

public static void main(String[] args) {
    BigInteger bigInteger = new BigInteger("2000000000000");// uper limit
    BigInteger min = new BigInteger("1000000000");// lower limit
    BigInteger bigInteger1 = bigInteger.subtract(min);
    Random rnd = new Random();
    int maxNumBitLength = bigInteger.bitLength();

    BigInteger aRandomBigInt;/*from  w w  w. j  ava 2  s.com*/

    aRandomBigInt = new BigInteger(maxNumBitLength, rnd);
    if (aRandomBigInt.compareTo(min) < 0)
        aRandomBigInt = aRandomBigInt.add(min);
    if (aRandomBigInt.compareTo(bigInteger) >= 0)
        aRandomBigInt = aRandomBigInt.mod(bigInteger1).add(min);

    System.out.println(aRandomBigInt);
}

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From source file:Main.java

License:asdf

public static void main(String[] args) {
    int howManyWords = 2;
    List<String> listOfWords = new ArrayList<>();
    Random random = new Random();
    listOfWords.addAll(Arrays.asList(randomMessages));
    List<String> selectedRandomMessages = new ArrayList<>();
    for (int i = 0; i < howManyWords; i++) {
        int randomNumber = random.nextInt(listOfWords.size());
        String randomItem = listOfWords.get(randomNumber);
        selectedRandomMessages.add(randomItem);
        listOfWords.remove(randomItem);/*w  w  w  . j a v  a  2  s. c o  m*/
    }
    System.out.println(selectedRandomMessages);
}

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From source file:Main.java

public static void main(final String[] args) throws Exception {
    Random RND = new Random();
    ExecutorService es = Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors());
    List<Future<String>> results = new ArrayList<>(10);
    for (int i = 0; i < 10; i++) {
        results.add(es.submit(new TimeSliceTask(RND.nextInt(10), TimeUnit.SECONDS)));
    }//from w ww  .  j a va2  s.c o m
    es.shutdown();
    while (!results.isEmpty()) {
        Iterator<Future<String>> i = results.iterator();
        while (i.hasNext()) {
            Future<String> f = i.next();
            if (f.isDone()) {
                System.out.println(f.get());
                i.remove();
            }
        }
    }
}

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From source file:Main.java

public static void main(String args[]) {
    // create Linked List
    List<Integer> list = new LinkedList<Integer>();

    // populate list
    list.add(5);//from  ww w.jav a 2 s  .c  om
    list.add(2);
    list.add(1);
    list.add(-3);

    System.out.println("List before shuffle: " + list);

    // shuffle the list
    Collections.shuffle(list, new Random());

    System.out.println("List after shuffle: " + list);
}

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From source file:com.prl.sort.InsertSort.java

/**
 * @param args/*  w  w  w.j  a v a  2  s.  c  o m*/
 */
public static void main(String[] args) {
    Integer[] arr = new Integer[10];
    Random random = new Random();
    int index = 0;
    while (true) {
        int num = random.nextInt(100) + 1;
        arr[index++] = num;
        if (index > 9) {
            break;
        }
    }

    System.out.println(StringUtils.join(arr, ","));

    int temp = 0;
    for (int i = 1; i < arr.length; i++) {
        int j = i - 1;
        temp = arr[i]; // ?
        // ???????
        for (; j >= 0 && arr[j] > temp; j--) {
            arr[j + 1] = arr[j];
            arr[j] = temp;
        }
    }

    System.out.println(StringUtils.join(arr, ","));
}

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From source file:HashCollider.java

/**i
 * @param args the command line arguments
 *//*  ww w.j a v a 2  s.  co m*/
public static void main(String[] args) {
    Random random = new Random();
    byte[] nbytes1 = new byte[64];
    byte[] nbytes2 = new byte[64];
    float average = 0;
    // set number of bits for checking collision
    int number_of_bits = 4;
    random.nextBytes(nbytes1);
    random.nextBytes(nbytes2);

    String sha1 = DigestUtils.sha256Hex(nbytes1);
    String sha2 = DigestUtils.sha256Hex(nbytes2);

    String nsh1 = new BigInteger(sha1, 16).toString(2);
    String nsh2 = new BigInteger(sha2, 16).toString(2);
    int i = 0;
    for (int j = 0; j < 5; j++) {
        while (true) {
            if (nsh1.substring(0, number_of_bits - 1).equals(nsh2.substring(0, number_of_bits - 1))) {
                System.out.println(i);
                average += i;
                break;
            }
            i++;
            //            System.out.println("......"+i);
            random.nextBytes(nbytes1);
            random.nextBytes(nbytes2);
            sha1 = DigestUtils.sha256Hex(nbytes1);
            sha2 = DigestUtils.sha256Hex(nbytes2);
            nsh1 = new BigInteger(sha1, 16).toString(2);
            nsh2 = new BigInteger(sha2, 16).toString(2);
        }
        i = 0;
        //        System.out.println(nsh1+"\n"+nsh2);
        random.nextBytes(nbytes1);
        random.nextBytes(nbytes2);
        sha1 = DigestUtils.sha256Hex(nbytes1);
        sha2 = DigestUtils.sha256Hex(nbytes2);
        nsh1 = new BigInteger(sha1, 16).toString(2);
        nsh2 = new BigInteger(sha2, 16).toString(2);

    }
    //
    System.out.println("Average for  " + number_of_bits + " bits is  " + average / 5);

}

---

From source file:Main.java

public static void main(String args[]) {
    JFrame frame = new JFrame("Button Sample");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    final JButton button1 = new JButton("Select Me");
    final JButton button2 = new JButton("No Select Me");
    final Random random = new Random();

    ActionListener actionListener = new ActionListener() {
        public void actionPerformed(ActionEvent actionEvent) {
            JButton button = (JButton) actionEvent.getSource();
            int red = random.nextInt(255);
            int green = random.nextInt(255);
            int blue = random.nextInt(255);
            button.setBackground(new Color(red, green, blue));
        }//  ww w.jav  a 2 s . c om
    };

    PropertyChangeListener propertyChangeListener = new PropertyChangeListener() {
        public void propertyChange(PropertyChangeEvent propertyChangeEvent) {
            String property = propertyChangeEvent.getPropertyName();
            if ("background".equals(property)) {
                button2.setBackground((Color) propertyChangeEvent.getNewValue());
            }
        }
    };

    button1.addActionListener(actionListener);
    button1.addPropertyChangeListener(propertyChangeListener);
    button2.addActionListener(actionListener);

    frame.add(button1, BorderLayout.NORTH);
    frame.add(button2, BorderLayout.SOUTH);
    frame.setSize(300, 100);
    frame.setVisible(true);
}

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From source file:Main.java

public static void main(String[] args) {
    JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    StyledDocument doc = new DefaultStyledDocument();
    JTextPane textPane = new JTextPane(doc);
    textPane.setText("this is a test.");

    Random random = new Random();
    for (int i = 0; i < textPane.getDocument().getLength(); i++) {
        SimpleAttributeSet set = new SimpleAttributeSet();
        StyleConstants.setForeground(set,
                new Color(random.nextInt(256), random.nextInt(256), random.nextInt(256)));
        StyleConstants.setFontSize(set, random.nextInt(12) + 12);
        StyleConstants.setBold(set, random.nextBoolean());
        StyleConstants.setItalic(set, random.nextBoolean());
        StyleConstants.setUnderline(set, random.nextBoolean());

        doc.setCharacterAttributes(i, 1, set, true);
    }//from  ww w  .j  a  v  a  2s  .c  o m

    frame.add(new JScrollPane(textPane));
    frame.setSize(500, 400);
    frame.setVisible(true);
}

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From source file:MathOps.java

public static void main(String[] args) {
    // Create a random number generator,
    // seeds with current time by default:

    Random rand = new Random();

    int i, j, k;//from ww  w  . ja  v  a  2s . c  o  m

    // Choose value from 1 to 100:

    j = rand.nextInt(100) + 1;

    k = rand.nextInt(100) + 1;

    printInt("j", j);
    printInt("k", k);

    i = j + k;
    printInt("j + k", i);

    i = j - k;
    printInt("j - k", i);

    i = k / j;
    printInt("k / j", i);

    i = k * j;
    printInt("k * j", i);

    i = k % j;
    printInt("k % j", i);

    j %= k;
    printInt("j %= k", j);

    // Floating-point number tests:

    float u, v, w; // applies to doubles, too

    v = rand.nextFloat();

    w = rand.nextFloat();

    printFloat("v", v);
    printFloat("w", w);

    u = v + w;
    printFloat("v + w", u);

    u = v - w;
    printFloat("v - w", u);

    u = v * w;
    printFloat("v * w", u);

    u = v / w;
    printFloat("v / w", u);

    // the following also works for

    // char, byte, short, int, long,

    // and double:

    u += v;
    printFloat("u += v", u);

    u -= v;
    printFloat("u -= v", u);

    u *= v;
    printFloat("u *= v", u);

    u /= v;
    printFloat("u /= v", u);

}

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From source file:PropertyChangeListenerDemo.java

public static void main(String args[]) {
    Runnable runner = new Runnable() {
        public void run() {
            JFrame frame = new JFrame("Button Sample");
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            final JButton button1 = new JButton("Select Me");
            final JButton button2 = new JButton("No Select Me");
            final Random random = new Random();
            // Define ActionListener
            ActionListener actionListener = new ActionListener() {
                public void actionPerformed(ActionEvent actionEvent) {
                    JButton button = (JButton) actionEvent.getSource();
                    int red = random.nextInt(255);
                    int green = random.nextInt(255);
                    int blue = random.nextInt(255);
                    button.setBackground(new Color(red, green, blue));
                }/*w  w w.ja v a 2s  .com*/
            };
            // Define PropertyChangeListener
            PropertyChangeListener propertyChangeListener = new PropertyChangeListener() {
                public void propertyChange(PropertyChangeEvent propertyChangeEvent) {
                    String property = propertyChangeEvent.getPropertyName();
                    if ("background".equals(property)) {
                        button2.setBackground((Color) propertyChangeEvent.getNewValue());
                    }
                }
            };
            button1.addActionListener(actionListener);
            button1.addPropertyChangeListener(propertyChangeListener);
            button2.addActionListener(actionListener);
            frame.add(button1, BorderLayout.NORTH);
            frame.add(button2, BorderLayout.SOUTH);
            frame.setSize(300, 100);
            frame.setVisible(true);
        }
    };
    EventQueue.invokeLater(runner);
}

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