1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 package org.apache.commons.math.random; 18 19 import java.util.Random; 20 21 /** 22 * Extension of <code>java.util.Random</code> wrapping a 23 * {@link RandomGenerator}. 24 * 25 * @since 1.1 26 * @version $Revision: 1003886 $ $Date: 2010-10-02 23:04:44 +0200 (sam. 02 oct. 2010) $ 27 */ 28 public class RandomAdaptor extends Random implements RandomGenerator { 29 30 /** Serializable version identifier. */ 31 private static final long serialVersionUID = 2306581345647615033L; 32 33 /** Wrapped randomGenerator instance */ 34 private final RandomGenerator randomGenerator; 35 36 /** 37 * Prevent instantiation without a generator argument 38 */ 39 @SuppressWarnings("unused") 40 private RandomAdaptor() { randomGenerator = null; } 41 42 /** 43 * Construct a RandomAdaptor wrapping the supplied RandomGenerator. 44 * 45 * @param randomGenerator the wrapped generator 46 */ 47 public RandomAdaptor(RandomGenerator randomGenerator) { 48 this.randomGenerator = randomGenerator; 49 } 50 51 /** 52 * Factory method to create a <code>Random</code> using the supplied 53 * <code>RandomGenerator</code>. 54 * 55 * @param randomGenerator wrapped RandomGenerator instance 56 * @return a Random instance wrapping the RandomGenerator 57 */ 58 public static Random createAdaptor(RandomGenerator randomGenerator) { 59 return new RandomAdaptor(randomGenerator); 60 } 61 62 /** 63 * Returns the next pseudorandom, uniformly distributed 64 * <code>boolean</code> value from this random number generator's 65 * sequence. 66 * 67 * @return the next pseudorandom, uniformly distributed 68 * <code>boolean</code> value from this random number generator's 69 * sequence 70 */ 71 @Override 72 public boolean nextBoolean() { 73 return randomGenerator.nextBoolean(); 74 } 75 76 /** 77 * Generates random bytes and places them into a user-supplied 78 * byte array. The number of random bytes produced is equal to 79 * the length of the byte array. 80 * 81 * @param bytes the non-null byte array in which to put the 82 * random bytes 83 */ 84 @Override 85 public void nextBytes(byte[] bytes) { 86 randomGenerator.nextBytes(bytes); 87 } 88 89 /** 90 * Returns the next pseudorandom, uniformly distributed 91 * <code>double</code> value between <code>0.0</code> and 92 * <code>1.0</code> from this random number generator's sequence. 93 * 94 * @return the next pseudorandom, uniformly distributed 95 * <code>double</code> value between <code>0.0</code> and 96 * <code>1.0</code> from this random number generator's sequence 97 */ 98 @Override 99 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 } 199
