src/java/org/apache/commons/lang/math/RandomUtils.java

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package org.apache.commons.lang.math;

import java.util.Random;

/**
 * <p><code>RandomUtils</code> is a wrapper that supports all possible 
 * {@link java.util.Random} methods via the {@link java.lang.Math#random()}
 * method and its system-wide <code>Random</code> object.
 * 
 * @author Henri Yandell
 * @since 2.0
 * @version $Id: RandomUtils.java,v 1.3 2003/07/14 22:25:05 bayard Exp $
 */
public final class RandomUtils {

    public static Random JVM_RANDOM = new JVMRandom();

// should be possible for JVM_RANDOM?
//    public static void nextBytes(byte[]) {
//    public synchronized double nextGaussian();
//    }

    /**
     * <p>Returns the next pseudorandom, uniformly distributed int value
     * from the Math.random() sequence.</p>
     *
     * @return the random int
     */
    public static int nextInt() {
        return nextInt(JVM_RANDOM);
    }
    public static int nextInt(Random rnd) {
        return rnd.nextInt();
    }
    /**
     * <p>Returns a pseudorandom, uniformly distributed int value
     * between <code>0</code> (inclusive) and the specified value
     * (exclusive), from the Math.random() sequence.</p>
     *
     * @param n  the specified exclusive max-value
     *
     * @return the random int
     */
    public static int nextInt(int n) {
        return nextInt(JVM_RANDOM, n);
    }
    public static int nextInt(Random rnd, int n) {
        // check this cannot return 'n'
        return rnd.nextInt(n);
    }
    /**
     * <p>Returns the next pseudorandom, uniformly distributed long value
     * from the Math.random() sequence.</p>
     *
     * @return the random long
     */
    public static long nextLong() {
        return nextLong(JVM_RANDOM);
    }
    public static long nextLong(Random rnd) {
        return rnd.nextLong();
    }
    /**
     * <p>Returns the next pseudorandom, uniformly distributed boolean value
     * from the Math.random() sequence.</p>
     *
     * @return the random boolean
     */
    public static boolean nextBoolean() {
        return nextBoolean(JVM_RANDOM);
    }
    public static boolean nextBoolean(Random rnd) {
        return rnd.nextBoolean();
    }
    /**
     * <p>Returns the next pseudorandom, uniformly distributed float value
     * between <code>0.0</code> and <code>1.0</code> from the Math.random()
     * sequence.</p>
     *
     * @return the random float
     */
    public static float nextFloat() {
        return nextFloat(JVM_RANDOM);
    }
    public static float nextFloat(Random rnd) {
        return rnd.nextFloat();
    }
    /**
     * <p>Synonymous to the Math.random() call.</p>
     *
     * @return the random double
     */
    public static double nextDouble() {
        return nextDouble(JVM_RANDOM);
    }
    public static double nextDouble(Random rnd) {
        return rnd.nextDouble();
    }
    
}