Example usage for java.lang Math random

Introduction

In this page you can find the example usage for java.lang Math random.

Prototype

public static double random()

Source Link

Document

Returns a double value with a positive sign, greater than or equal to 0.0 and less than 1.0 .

Usage

From source file:Main.java

@SuppressWarnings("unused")
public static String getRandomNumber(int count) {
    Random rdm = new Random(System.currentTimeMillis());
    String random = "";
    for (int i = 0; i < count; i++) {
        String str = String.valueOf((int) (Math.random() * 10 - 1));
        random = random + str;// w ww.  j  a  va 2s  .c  om
    }
    return random;
}

From source file:Main.java

public static String getRandomString(int len) {
    StringBuffer sb = new StringBuffer(len);
    for (int i = 0; i < len; i++) {
        int ndx = (int) (Math.random() * ALPHA_NUM.length());
        sb.append(ALPHA_NUM.charAt(ndx));
    }//ww w  .  j  a v  a  2  s  .  co m
    return sb.toString();
}

From source file:Main.java

/**
 * Generate a random message-id header for locally-generated messages.
 *///from   w ww . j av  a 2  s.c om
public static String generateMessageId() {
    StringBuffer sb = new StringBuffer();
    sb.append("<");
    for (int i = 0; i < 24; i++) {
        sb.append(Integer.toString((int) (Math.random() * 35), 36));
    }
    sb.append(".");
    sb.append(Long.toString(System.currentTimeMillis()));
    sb.append("@email.android.com>");
    return sb.toString();
}

From source file:MainClass.java

public static int randomInt(int low, int high) {
    int result = (int) (Math.random() * (high - low + 1)) + low;
    return result;
}

From source file:Main.java

public static int[] randomColor(int size) {
    int[] returncolors = new int[size];
    for (int i = 0; i < size; i++) {
        returncolors[i] = colors[(int) (Math.random() * 6)];
    }/*from ww  w  .ja  va  2s .c  o  m*/
    return returncolors;
}

From source file:Main.java

/** Sleeps between floor and ceiling milliseconds, chosen randomly */
public static void sleepRandom(long floor, long ceiling) {
    if (ceiling - floor <= 0) {
        return;/*from www  .  j a  va 2  s  .co m*/
    }
    long diff = ceiling - floor;
    long r = (int) ((Math.random() * 100000) % diff) + floor;
    sleep(r);
}

From source file:Main.java

public static int roll() {
    return (int) Math.ceil(Math.random() * 6);
}

From source file:Main.java

public static Date getRandomDate() {
    final long beginTime = Timestamp.valueOf("2017-01-13 00:00:00").getTime();
    final long endTime = Timestamp.valueOf("2017-02-14 00:58:00").getTime();
    long diff = endTime - beginTime + 1;

    long timeStamp = beginTime + (long) (Math.random() * diff);
    return new Date(timeStamp);
}

From source file:Main.java

public static List<Double> populateDoubleList(int numberOfItems) {
    List<Double> dummyDoubleList = null;
    if (numberOfItems > 0) {
        dummyDoubleList = new ArrayList<Double>();
        for (int i = 0; i < numberOfItems; i++) {
            final double randomNumber = (Math.random() * numberOfItems);
            dummyDoubleList.add(randomNumber);
        }/*from  ww w .  ja va  2  s.  c om*/
    }
    return dummyDoubleList;
}

From source file:Main.java

public static String[] populateStringArray(int numberOfItems) {
    final String partialWord = "partialArrayParallel";
    String[] dummyStringArray = null;
    if (numberOfItems > 0) {
        dummyStringArray = new String[numberOfItems];
        for (int i = 0; i < numberOfItems; i++) {
            final double randomNumber = (Math.random() * numberOfItems);
            final StringBuilder sb = new StringBuilder(partialWord).append(randomNumber);
            dummyStringArray[i] = sb.toString();
        }// w  ww.  ja v a  2  s.  c  o  m
    }
    return dummyStringArray;
}