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.io.Serializable; 20 21 /** 22 * Interface extracted from <code>java.util.Random</code>. This interface is 23 * implemented by {@link AbstractRandomGenerator}. 24 * 25 * @since 1.1 26 * @version $Revision: 628614 $ $Date: 2008-02-17 21:47:53 -0700 (Sun, 17 Feb 2008) $ 27 */ 28 public interface RandomGenerator extends Serializable { 29 30 /** 31 * Sets the seed of the underyling random number generator using a 32 * <code>long</code> seed. Sequences of values generated starting with the 33 * same seeds should be identical. 34 * 35 * @param seed the seed value 36 */ 37 void setSeed(long seed); 38 39 /** 40 * Generates random bytes and places them into a user-supplied 41 * byte array. The number of random bytes produced is equal to 42 * the length of the byte array. 43 * 44 * @param bytes the non-null byte array in which to put the 45 * random bytes 46 */ 47 void nextBytes(byte[] bytes); 48 49 /** 50 * Returns the next pseudorandom, uniformly distributed <code>int</code> 51 * value from this random number generator's sequence. 52 * All 2<font size="-1"><sup>32</sup></font> possible <tt>int</tt> values 53 * should be produced with (approximately) equal probability. 54 * 55 * @return the next pseudorandom, uniformly distributed <code>int</code> 56 * value from this random number generator's sequence 57 */ 58 int nextInt(); 59 60 /** 61 * Returns a pseudorandom, uniformly distributed <tt>int</tt> value 62 * between 0 (inclusive) and the specified value (exclusive), drawn from 63 * this random number generator's sequence. 64 * 65 * @param n the bound on the random number to be returned. Must be 66 * positive. 67 * @return a pseudorandom, uniformly distributed <tt>int</tt> 68 * value between 0 (inclusive) and n (exclusive). 69 * @throws IllegalArgumentException if n is not positive. 70 */ 71 int nextInt(int n); 72 73 /** 74 * Returns the next pseudorandom, uniformly distributed <code>long</code> 75 * value from this random number generator's sequence. All 76 * 2<font size="-1"><sup>64</sup></font> possible <tt>long</tt> values 77 * should be produced with (approximately) equal probability. 78 * 79 * @return the next pseudorandom, uniformly distributed <code>long</code> 80 *value from this random number generator's sequence 81 */ 82 long nextLong(); 83 84 /** 85 * Returns the next pseudorandom, uniformly distributed 86 * <code>boolean</code> value from this random number generator's 87 * sequence. 88 * 89 * @return the next pseudorandom, uniformly distributed 90 * <code>boolean</code> value from this random number generator's 91 * sequence 92 */ 93 boolean nextBoolean(); 94 95 /** 96 * Returns the next pseudorandom, uniformly distributed <code>float</code> 97 * value between <code>0.0</code> and <code>1.0</code> from this random 98 * number generator's sequence. 99 * 100 * @return the next pseudorandom, uniformly distributed <code>float</code> 101 * value between <code>0.0</code> and <code>1.0</code> from this 102 * random number generator's sequence 103 */ 104 float nextFloat(); 105 106 /** 107 * Returns the next pseudorandom, uniformly distributed 108 * <code>double</code> value between <code>0.0</code> and 109 * <code>1.0</code> from this random number generator's sequence. 110 * 111 * @return the next pseudorandom, uniformly distributed 112 * <code>double</code> value between <code>0.0</code> and 113 * <code>1.0</code> from this random number generator's sequence 114 */ 115 double nextDouble(); 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 double nextGaussian(); 128 }