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Java random

Submitted by jmaselj on Fri, 07/10/2009 - 08:30.
Tags:

Hi!
I'm new and wanted to show a class i use to randomize arrays.

import java.lang.reflect.Array;

/**
* Free use;
* @author maseljj
*/
public final class Randomizer {

    private Randomizer() {
    }

    /**
     * Randomly returnes one of two states: True or false;
     * @return boolean;
     */
    public static boolean rndState() {

        //generate random hash number;
        short s = (short) ((int) new Randomizer().hashCode() % 2);
        if (s == 1) {
            return true;
        }
        return false;
    }

    /**
     * Returnes random value from input;
     * @param fromRange
     * @param toRange
     * @return random int from to;
     */
    public static int getRndValue(int fromRange, int toRange) {

        int rndResult = 0;

        int mapSize = (toRange - fromRange);
        int mapCurrentVal = fromRange;

        int rndNmb = 0;
        int champion = 0;
        for (int i = 0; i <= mapSize; i++) {
            rndNmb = new Randomizer().hashCode();
            if (!Randomizer.isFirstValGreatest(champion, rndNmb)) {
                champion = rndNmb;
                rndResult = mapCurrentVal;
            }
            mapCurrentVal++;

        }
        return rndResult;
    }

    /**
     * Randomize whole array;
     * @param o
     * @return randomized array;
     */
    public static Object[] rndomizeArray(Object[] o) {
        if (o == null) {
            return o;
        }

        int inObjLen = Array.getLength(o);
        Object[] retArray = new Object[inObjLen];
        boolean[] ocupiedFields = new boolean[inObjLen];

        for (int i = 0; i < inObjLen; i++) {
            Object tmpO = o[i];
            boolean ocupied = true;
            int rndVal = 0;

            while (ocupied) {
                rndVal = Randomizer.getRndValue(0, (inObjLen - 1));
                if (!ocupiedFields[rndVal]) {
                    ocupied = false;
                    ocupiedFields[rndVal] = true;
                }
            }

            retArray[rndVal] = tmpO;
        }

        return retArray;
    }

    /**
     * Randomize whole array;
     * @param o
     * @return randomized array;
     */
    public static int[] rndomizeArray(int o[]) {
        if (o == null) {
            return o;
        }
        int inObjLen = Array.getLength(o);
        int[] retArray = new int[inObjLen];
        boolean[] ocupiedFields = new boolean[inObjLen];

        for (int i = 0; i < inObjLen; i++) {
            int tmpO = o[i];
            boolean ocupied = true;
            int rndVal = 0;

            while (ocupied) {
                rndVal = Randomizer.getRndValue(0, (inObjLen - 1));
                if (!ocupiedFields[rndVal]) {
                    ocupied = false;
                    ocupiedFields[rndVal] = true;
                }
            }

            retArray[rndVal] = tmpO;
        }

        return retArray;
    }

    /**
     * Returnes random value from array;
     * @param o
     * @return random array value;
     */
    public static Object getRndArrayVal(Object[] o) {
        if ((o != null) && (Array.getLength(o) > 0)) {
            return o[Randomizer.getRndValue(0, (Array.getLength(o) - 1))];
        }
        return o;
    }

    /**
     * If first input value is larger than second value, returns true,
     * otherweise false;
     * @param c1
     * @param c2
     * @return boolean according to input;
     */
    private static boolean isFirstValGreatest(int c1, int c2) {
        if (c1 < c2) {
            return false;
        }
        return true;
    }
}

Comments are welcome. Stay cool.