Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You 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 org.apache.commons.math.random; import java.util.Random; /** * Extension of <code>java.util.Random</code> wrapping a * {@link RandomGenerator}. * * @since 1.1 * @version $Revision: 1003886 $ $Date: 2010-10-02 23:04:44 +0200 (sam. 02 oct. 2010) $ */ public class RandomAdaptor extends Random implements RandomGenerator { /** Serializable version identifier. */ private static final long serialVersionUID = 2306581345647615033L; /** Wrapped randomGenerator instance */ private final RandomGenerator randomGenerator; /** * Prevent instantiation without a generator argument */ @SuppressWarnings("unused") private RandomAdaptor() { randomGenerator = null; } /** * Construct a RandomAdaptor wrapping the supplied RandomGenerator. * * @param randomGenerator the wrapped generator */ public RandomAdaptor(RandomGenerator randomGenerator) { this.randomGenerator = randomGenerator; } /** * Factory method to create a <code>Random</code> using the supplied * <code>RandomGenerator</code>. * * @param randomGenerator wrapped RandomGenerator instance * @return a Random instance wrapping the RandomGenerator */ public static Random createAdaptor(RandomGenerator randomGenerator) { return new RandomAdaptor(randomGenerator); } /** * Returns the next pseudorandom, uniformly distributed * <code>boolean</code> value from this random number generator's * sequence. * * @return the next pseudorandom, uniformly distributed * <code>boolean</code> value from this random number generator's * sequence */ @Override public boolean nextBoolean() { return randomGenerator.nextBoolean(); } /** * Generates random bytes and places them into a user-supplied * byte array. The number of random bytes produced is equal to * the length of the byte array. * * @param bytes the non-null byte array in which to put the * random bytes */ @Override public void nextBytes(byte[] bytes) { randomGenerator.nextBytes(bytes); } /** * Returns the next pseudorandom, uniformly distributed * <code>double</code> value between <code>0.0</code> and * <code>1.0</code> from this random number generator's sequence. * * @return the next pseudorandom, uniformly distributed * <code>double</code> value between <code>0.0</code> and * <code>1.0</code> from this random number generator's sequence */ @Override public double nextDouble() { return randomGenerator.nextDouble(); } /** * Returns the next pseudorandom, uniformly distributed <code>float</code> * value between <code>0.0</code> and <code>1.0</code> from this random * number generator's sequence. * * @return the next pseudorandom, uniformly distributed <code>float</code> * value between <code>0.0</code> and <code>1.0</code> from this * random number generator's sequence */ @Override public float nextFloat() { return randomGenerator.nextFloat(); } /** * Returns the next pseudorandom, Gaussian ("normally") distributed * <code>double</code> value with mean <code>0.0</code> and standard * deviation <code>1.0</code> from this random number generator's sequence. * * @return the next pseudorandom, Gaussian ("normally") distributed * <code>double</code> value with mean <code>0.0</code> and * standard deviation <code>1.0</code> from this random number * generator's sequence */ @Override public double nextGaussian() { return randomGenerator.nextGaussian(); } /** * Returns the next pseudorandom, uniformly distributed <code>int</code> * value from this random number generator's sequence. * All 2<font size="-1"><sup>32</sup></font> possible <tt>int</tt> values * should be produced with (approximately) equal probability. * * @return the next pseudorandom, uniformly distributed <code>int</code> * value from this random number generator's sequence */ @Override public int nextInt() { return randomGenerator.nextInt(); } /** * Returns a pseudorandom, uniformly distributed <tt>int</tt> value * between 0 (inclusive) and the specified value (exclusive), drawn from * this random number generator's sequence. * * @param n the bound on the random number to be returned. Must be * positive. * @return a pseudorandom, uniformly distributed <tt>int</tt> * value between 0 (inclusive) and n (exclusive). * @throws IllegalArgumentException if n is not positive. */ @Override public int nextInt(int n) { return randomGenerator.nextInt(n); } /** * Returns the next pseudorandom, uniformly distributed <code>long</code> * value from this random number generator's sequence. All * 2<font size="-1"><sup>64</sup></font> possible <tt>long</tt> values * should be produced with (approximately) equal probability. * * @return the next pseudorandom, uniformly distributed <code>long</code> *value from this random number generator's sequence */ @Override public long nextLong() { return randomGenerator.nextLong(); } /** {@inheritDoc} */ public void setSeed(int seed) { if (randomGenerator != null) { // required to avoid NPE in constructor randomGenerator.setSeed(seed); } } /** {@inheritDoc} */ public void setSeed(int[] seed) { if (randomGenerator != null) { // required to avoid NPE in constructor randomGenerator.setSeed(seed); } } /** {@inheritDoc} */ @Override public void setSeed(long seed) { if (randomGenerator != null) { // required to avoid NPE in constructor randomGenerator.setSeed(seed); } } }