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 20 /** 21 * Interface extracted from <code>java.util.Random</code>. This interface is 22 * implemented by {@link AbstractRandomGenerator}. 23 * 24 * @since 1.1 25 * @version $Revision: 949750 $ $Date: 2010-05-31 16:06:04 +0200 (lun. 31 mai 2010) $ 26 */ 27 public interface RandomGenerator { 28 29 /** 30 * Sets the seed of the underlying random number generator using an 31 * <code>int</code> seed. 32 * <p>Sequences of values generated starting with the same seeds 33 * should be identical. 34 * </p> 35 * @param seed the seed value 36 */ 37 void setSeed(int seed); 38 39 /** 40 * Sets the seed of the underlying random number generator using an 41 * <code>int</code> array seed. 42 * <p>Sequences of values generated starting with the same seeds 43 * should be identical. 44 * </p> 45 * @param seed the seed value 46 */ 47 void setSeed(int[] seed); 48 49 /** 50 * Sets the seed of the underlying random number generator using a 51 * <code>long</code> seed. 52 * <p>Sequences of values generated starting with the same seeds 53 * should be identical. 54 * </p> 55 * @param seed the seed value 56 */ 57 void setSeed(long seed); 58 59 /** 60 * Generates random bytes and places them into a user-supplied 61 * byte array. The number of random bytes produced is equal to 62 * the length of the byte array. 63 * 64 * @param bytes the non-null byte array in which to put the 65 * random bytes 66 */ 67 void nextBytes(byte[] bytes); 68 69 /** 70 * Returns the next pseudorandom, uniformly distributed <code>int</code> 71 * value from this random number generator's sequence. 72 * All 2<font size="-1"><sup>32</sup></font> possible <tt>int</tt> values 73 * should be produced with (approximately) equal probability. 74 * 75 * @return the next pseudorandom, uniformly distributed <code>int</code> 76 * value from this random number generator's sequence 77 */ 78 int nextInt(); 79 80 /** 81 * Returns a pseudorandom, uniformly distributed <tt>int</tt> value 82 * between 0 (inclusive) and the specified value (exclusive), drawn from 83 * this random number generator's sequence. 84 * 85 * @param n the bound on the random number to be returned. Must be 86 * positive. 87 * @return a pseudorandom, uniformly distributed <tt>int</tt> 88 * value between 0 (inclusive) and n (exclusive). 89 * @throws IllegalArgumentException if n is not positive. 90 */ 91 int nextInt(int n); 92 93 /** 94 * Returns the next pseudorandom, uniformly distributed <code>long</code> 95 * value from this random number generator's sequence. All 96 * 2<font size="-1"><sup>64</sup></font> possible <tt>long</tt> values 97 * should be produced with (approximately) equal probability. 98 * 99 * @return the next pseudorandom, uniformly distributed <code>long</code> 100 *value from this random number generator's sequence 101 */ 102 long nextLong(); 103 104 /** 105 * Returns the next pseudorandom, uniformly distributed 106 * <code>boolean</code> value from this random number generator's 107 * sequence. 108 * 109 * @return the next pseudorandom, uniformly distributed 110 * <code>boolean</code> value from this random number generator's 111 * sequence 112 */ 113 boolean nextBoolean(); 114 115 /** 116 * Returns the next pseudorandom, uniformly distributed <code>float</code> 117 * value between <code>0.0</code> and <code>1.0</code> from this random 118 * number generator's sequence. 119 * 120 * @return the next pseudorandom, uniformly distributed <code>float</code> 121 * value between <code>0.0</code> and <code>1.0</code> from this 122 * random number generator's sequence 123 */ 124 float nextFloat(); 125 126 /** 127 * Returns the next pseudorandom, uniformly distributed 128 * <code>double</code> value between <code>0.0</code> and 129 * <code>1.0</code> from this random number generator's sequence. 130 * 131 * @return the next pseudorandom, uniformly distributed 132 * <code>double</code> value between <code>0.0</code> and 133 * <code>1.0</code> from this random number generator's sequence 134 */ 135 double nextDouble(); 136 137 /** 138 * Returns the next pseudorandom, Gaussian ("normally") distributed 139 * <code>double</code> value with mean <code>0.0</code> and standard 140 * deviation <code>1.0</code> from this random number generator's sequence. 141 * 142 * @return the next pseudorandom, Gaussian ("normally") distributed 143 * <code>double</code> value with mean <code>0.0</code> and 144 * standard deviation <code>1.0</code> from this random number 145 * generator's sequence 146 */ 147 double nextGaussian(); 148 } 149
