KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > org > apache > commons > math > random > RandomGenerator


1 /*
2  * Copyright 2005 The Apache Software Foundation.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 package org.apache.commons.math.random;
17
18 /**
19  * Interface extracted from <code>java.util.Random</code>. This interface is
20  * implemented by {@link AbstractRandomGenerator}.
21  *
22  * @since 1.1
23  * @version $Revision:$ $Date$
24  */
25 public interface RandomGenerator {
26     
27     /**
28      * Sets the seed of the underyling random number generator using a
29      * <code>long</code> seed. Sequences of values generated starting with the
30      * same seeds should be identical.
31      *
32      * @param seed the seed value
33      */
34     void setSeed(long seed);
35     
36     /**
37      * Generates random bytes and places them into a user-supplied
38      * byte array. The number of random bytes produced is equal to
39      * the length of the byte array.
40      *
41      * @param bytes the non-null byte array in which to put the
42      * random bytes
43      */
44     void nextBytes(byte[] bytes);
45     
46     /**
47      * Returns the next pseudorandom, uniformly distributed <code>int</code>
48      * value from this random number generator's sequence.
49      * All 2<font size="-1"><sup>32</sup></font> possible <tt>int</tt> values
50      * should be produced with (approximately) equal probability.
51      *
52      * @return the next pseudorandom, uniformly distributed <code>int</code>
53      * value from this random number generator's sequence
54      */
55     int nextInt();
56     
57     /**
58      * Returns a pseudorandom, uniformly distributed <tt>int</tt> value
59      * between 0 (inclusive) and the specified value (exclusive), drawn from
60      * this random number generator's sequence.
61      *
62      * @param n the bound on the random number to be returned. Must be
63      * positive.
64      * @return a pseudorandom, uniformly distributed <tt>int</tt>
65      * value between 0 (inclusive) and n (exclusive).
66      * @throws IllegalArgumentException if n is not positive.
67      */
68     int nextInt(int n);
69     
70     /**
71      * Returns the next pseudorandom, uniformly distributed <code>long</code>
72      * value from this random number generator's sequence. All
73      * 2<font size="-1"><sup>64</sup></font> possible <tt>long</tt> values
74      * should be produced with (approximately) equal probability.
75      *
76      * @return the next pseudorandom, uniformly distributed <code>long</code>
77      *value from this random number generator's sequence
78      */
79     long nextLong();
80     
81     /**
82      * Returns the next pseudorandom, uniformly distributed
83      * <code>boolean</code> value from this random number generator's
84      * sequence.
85      *
86      * @return the next pseudorandom, uniformly distributed
87      * <code>boolean</code> value from this random number generator's
88      * sequence
89      */
90     boolean nextBoolean();
91     
92     /**
93      * Returns the next pseudorandom, uniformly distributed <code>float</code>
94      * value between <code>0.0</code> and <code>1.0</code> from this random
95      * number generator's sequence.
96      *
97      * @return the next pseudorandom, uniformly distributed <code>float</code>
98      * value between <code>0.0</code> and <code>1.0</code> from this
99      * random number generator's sequence
100      */
101     float nextFloat();
102     
103     /**
104      * Returns the next pseudorandom, uniformly distributed
105      * <code>double</code> value between <code>0.0</code> and
106      * <code>1.0</code> from this random number generator's sequence.
107      *
108      * @return the next pseudorandom, uniformly distributed
109      * <code>double</code> value between <code>0.0</code> and
110      * <code>1.0</code> from this random number generator's sequence
111      */
112     double nextDouble();
113     
114     /**
115      * Returns the next pseudorandom, Gaussian ("normally") distributed
116      * <code>double</code> value with mean <code>0.0</code> and standard
117      * deviation <code>1.0</code> from this random number generator's sequence.
118      *
119      * @return the next pseudorandom, Gaussian ("normally") distributed
120      * <code>double</code> value with mean <code>0.0</code> and
121      * standard deviation <code>1.0</code> from this random number
122      * generator's sequence
123      */
124     double nextGaussian();
125 }
126
Popular Tags