RandomSource.java

/*
 * Apache License
 * Version 2.0, January 2004
 * http://www.apache.org/licenses/
 *
 *    Copyright 2013 Aurelian Tutuianu
 *    Copyright 2014 Aurelian Tutuianu
 *    Copyright 2015 Aurelian Tutuianu
 *    Copyright 2016 Aurelian Tutuianu
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 *
 */

package rapaio.core;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.Serializable;
import java.math.BigInteger;
import java.security.SecureRandom;
import java.util.Random;

/**
 * Random number producer used by rapaio facilities.
 * <p>
 * For now the implementation uses the standard Java {@link Random}.
 * <p>
 * In order to have a reproducible analysis you can use
 * same seed in code ({@link #setSeed(long)}).
 *
 * @author Aurelian Tutuianu
 */
public final class RandomSource implements Serializable {

    private static final long serialVersionUID = -1201316989986445607L;
    private static Random rand = new Random();

    public static void setSeed(long seed) {
        rand.setSeed(seed);
    }

    public static void withUtilRandom(long seed) {
        rand = new Random(seed);
    }

    public static void withSecureRandom(byte[] seed) {
        rand = new SecureRandom(seed);
    }

    /**
     * Returns the next pseudorandom, uniformly distributed
     * {@code double} value between {@code 0.0} and
     * {@code 1.0} from this random number generator's sequence.
     */
    public static double nextDouble() {
        return rand.nextDouble();
    }

    public static int nextInt(int n) {
        return rand.nextInt(n);
    }

    public static long nextLong() {
        return rand.nextLong();
    }

    public static String nextString(int len) {
        return new BigInteger(len, rand).toString();
    }

    public static Random getRandom() {
        return rand;
    }
}