    001    /*
    002     * Licensed to the Apache Software Foundation (ASF) under one or more
    003     * contributor license agreements.  See the NOTICE file distributed with
    004     * this work for additional information regarding copyright ownership.
    005     * The ASF licenses this file to You under the Apache License, Version 2.0
    006     * (the "License"); you may not use this file except in compliance with
    007     * the License.  You may obtain a copy of the License at
    008     *
    009     *      http://www.apache.org/licenses/LICENSE-2.0
    010     *
    011     * Unless required by applicable law or agreed to in writing, software
    012     * distributed under the License is distributed on an "AS IS" BASIS,
    013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014     * See the License for the specific language governing permissions and
    015     * limitations under the License.
    016     */
    017    package org.apache.commons.math.random;
    018
    019    import java.util.Random;
    020
    021    /**
    022     * Extension of <code>java.util.Random</code> wrapping a
    023     * {@link RandomGenerator}.
    024     *
    025     * @since 1.1
    026     * @version $Revision: 1003886 $ $Date: 2010-10-02 23:04:44 +0200 (sam. 02 oct. 2010) $
    027     */
    028    public class RandomAdaptor extends Random implements RandomGenerator {
    029
    030        /** Serializable version identifier. */
    031        private static final long serialVersionUID = 2306581345647615033L;
    032
    033        /** Wrapped randomGenerator instance */
    034        private final RandomGenerator randomGenerator;
    035
    036        /**
    037         * Prevent instantiation without a generator argument
    038         */
    039        @SuppressWarnings("unused")
    040        private RandomAdaptor() { randomGenerator = null; }
    041
    042        /**
    043         * Construct a RandomAdaptor wrapping the supplied RandomGenerator.
    044         *
    045         * @param randomGenerator  the wrapped generator
    046         */
    047        public RandomAdaptor(RandomGenerator randomGenerator) {
    048            this.randomGenerator = randomGenerator;
    049        }
    050
    051        /**
    052         * Factory method to create a <code>Random</code> using the supplied
    053         * <code>RandomGenerator</code>.
    054         *
    055         * @param randomGenerator  wrapped RandomGenerator instance
    056         * @return a Random instance wrapping the RandomGenerator
    057         */
    058        public static Random createAdaptor(RandomGenerator randomGenerator) {
    059            return new RandomAdaptor(randomGenerator);
    060        }
    061
    062        /**
    063         * Returns the next pseudorandom, uniformly distributed
    064         * <code>boolean</code> value from this random number generator's
    065         * sequence.
    066         *
    067         * @return  the next pseudorandom, uniformly distributed
    068         * <code>boolean</code> value from this random number generator's
    069         * sequence
    070         */
    071        @Override
    072        public boolean nextBoolean() {
    073            return randomGenerator.nextBoolean();
    074        }
    075
    076         /**
    077         * Generates random bytes and places them into a user-supplied
    078         * byte array.  The number of random bytes produced is equal to
    079         * the length of the byte array.
    080         *
    081         * @param bytes the non-null byte array in which to put the
    082         * random bytes
    083         */
    084        @Override
    085        public void nextBytes(byte[] bytes) {
    086            randomGenerator.nextBytes(bytes);
    087        }
    088
    089         /**
    090         * Returns the next pseudorandom, uniformly distributed
    091         * <code>double</code> value between <code>0.0</code> and
    092         * <code>1.0</code> from this random number generator's sequence.
    093         *
    094         * @return  the next pseudorandom, uniformly distributed
    095         *  <code>double</code> value between <code>0.0</code> and
    096         *  <code>1.0</code> from this random number generator's sequence
    097         */
    098        @Override
    099        public double nextDouble() {
    100            return randomGenerator.nextDouble();
    101        }
    102
    103        /**
    104         * Returns the next pseudorandom, uniformly distributed <code>float</code>
    105         * value between <code>0.0</code> and <code>1.0</code> from this random
    106         * number generator's sequence.
    107         *
    108         * @return  the next pseudorandom, uniformly distributed <code>float</code>
    109         * value between <code>0.0</code> and <code>1.0</code> from this
    110         * random number generator's sequence
    111         */
    112        @Override
    113        public float nextFloat() {
    114            return randomGenerator.nextFloat();
    115        }
    116
    117        /**
    118         * Returns the next pseudorandom, Gaussian ("normally") distributed
    119         * <code>double</code> value with mean <code>0.0</code> and standard
    120         * deviation <code>1.0</code> from this random number generator's sequence.
    121         *
    122         * @return  the next pseudorandom, Gaussian ("normally") distributed
    123         * <code>double</code> value with mean <code>0.0</code> and
    124         * standard deviation <code>1.0</code> from this random number
    125         *  generator's sequence
    126         */
    127        @Override
    128        public double nextGaussian() {
    129            return randomGenerator.nextGaussian();
    130        }
    131
    132         /**
    133         * Returns the next pseudorandom, uniformly distributed <code>int</code>
    134         * value from this random number generator's sequence.
    135         * All 2<font size="-1"><sup>32</sup></font> possible <tt>int</tt> values
    136         * should be produced with  (approximately) equal probability.
    137         *
    138         * @return the next pseudorandom, uniformly distributed <code>int</code>
    139         *  value from this random number generator's sequence
    140         */
    141        @Override
    142        public int nextInt() {
    143            return randomGenerator.nextInt();
    144        }
    145
    146        /**
    147         * Returns a pseudorandom, uniformly distributed <tt>int</tt> value
    148         * between 0 (inclusive) and the specified value (exclusive), drawn from
    149         * this random number generator's sequence.
    150         *
    151         * @param n the bound on the random number to be returned.  Must be
    152         * positive.
    153         * @return  a pseudorandom, uniformly distributed <tt>int</tt>
    154         * value between 0 (inclusive) and n (exclusive).
    155         * @throws IllegalArgumentException  if n is not positive.
    156         */
    157        @Override
    158        public int nextInt(int n) {
    159            return randomGenerator.nextInt(n);
    160        }
    161
    162        /**
    163         * Returns the next pseudorandom, uniformly distributed <code>long</code>
    164         * value from this random number generator's sequence.  All
    165         * 2<font size="-1"><sup>64</sup></font> possible <tt>long</tt> values
    166         * should be produced with (approximately) equal probability.
    167         *
    168         * @return  the next pseudorandom, uniformly distributed <code>long</code>
    169         *value from this random number generator's sequence
    170         */
    171        @Override
    172        public long nextLong() {
    173            return randomGenerator.nextLong();
    174        }
    175
    176        /** {@inheritDoc} */
    177        public void setSeed(int seed) {
    178            if (randomGenerator != null) {  // required to avoid NPE in constructor
    179                randomGenerator.setSeed(seed);
    180            }
    181        }
    182
    183        /** {@inheritDoc} */
    184        public void setSeed(int[] seed) {
    185            if (randomGenerator != null) {  // required to avoid NPE in constructor
    186                randomGenerator.setSeed(seed);
    187            }
    188        }
    189
    190        /** {@inheritDoc} */
    191        @Override
    192        public void setSeed(long seed) {
    193            if (randomGenerator != null) {  // required to avoid NPE in constructor
    194                randomGenerator.setSeed(seed);
    195            }
    196        }
    197
    198    }