1. /* ====================================================================
  2. * The Apache Software License, Version 1.1
  3. *
  4. * Copyright (c) 2002 The Apache Software Foundation. All rights
  5. * reserved.
  6. *
  7. * Redistribution and use in source and binary forms, with or without
  8. * modification, are permitted provided that the following conditions
  9. * are met:
  10. *
  11. * 1. Redistributions of source code must retain the above copyright
  12. * notice, this list of conditions and the following disclaimer.
  13. *
  14. * 2. Redistributions in binary form must reproduce the above copyright
  15. * notice, this list of conditions and the following disclaimer in
  16. * the documentation and/or other materials provided with the
  17. * distribution.
  18. *
  19. * 3. The end-user documentation included with the redistribution, if
  20. * any, must include the following acknowledgement:
  21. * "This product includes software developed by the
  22. * Apache Software Foundation (http://www.apache.org/)."
  23. * Alternately, this acknowledgement may appear in the software itself,
  24. * if and wherever such third-party acknowledgements normally appear.
  25. *
  26. * 4. The names "The Jakarta Project", "Commons", and "Apache Software
  27. * Foundation" must not be used to endorse or promote products derived
  28. * from this software without prior written permission. For written
  29. * permission, please contact apache@apache.org.
  30. *
  31. * 5. Products derived from this software may not be called "Apache"
  32. * nor may "Apache" appear in their names without prior written
  33. * permission of the Apache Software Foundation.
  34. *
  35. * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
  36. * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  37. * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  38. * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
  39. * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  40. * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  41. * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  42. * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  43. * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  44. * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  45. * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  46. * SUCH DAMAGE.
  47. * ====================================================================
  48. *
  49. * This software consists of voluntary contributions made by many
  50. * individuals on behalf of the Apache Software Foundation. For more
  51. * information on the Apache Software Foundation, please see
  52. * <http://www.apache.org/>.
  53. */
  54. package org.apache.commons.lang.math;
  55. import java.util.Random;
  56. /**
  57. * <p><code>RandomUtils</code> is a wrapper that supports all possible
  58. * {@link java.util.Random} methods via the {@link java.lang.Math#random()}
  59. * method and its system-wide <code>Random</code> object.
  60. *
  61. * @author Henri Yandell
  62. * @since 2.0
  63. * @version $Id: RandomUtils.java,v 1.6 2003/08/18 02:22:24 bayard Exp $
  64. */
  65. public class RandomUtils {
  66. public static final Random JVM_RANDOM = new JVMRandom();
  67. // should be possible for JVM_RANDOM?
  68. // public static void nextBytes(byte[]) {
  69. // public synchronized double nextGaussian();
  70. // }
  71. /**
  72. * <p>Returns the next pseudorandom, uniformly distributed int value
  73. * from the Math.random() sequence.</p>
  74. *
  75. * @return the random int
  76. */
  77. public static int nextInt() {
  78. return nextInt(JVM_RANDOM);
  79. }
  80. public static int nextInt(Random rnd) {
  81. return rnd.nextInt();
  82. }
  83. /**
  84. * <p>Returns a pseudorandom, uniformly distributed int value
  85. * between <code>0</code> (inclusive) and the specified value
  86. * (exclusive), from the Math.random() sequence.</p>
  87. *
  88. * @param n the specified exclusive max-value
  89. *
  90. * @return the random int
  91. */
  92. public static int nextInt(int n) {
  93. return nextInt(JVM_RANDOM, n);
  94. }
  95. public static int nextInt(Random rnd, int n) {
  96. // check this cannot return 'n'
  97. return rnd.nextInt(n);
  98. }
  99. /**
  100. * <p>Returns the next pseudorandom, uniformly distributed long value
  101. * from the Math.random() sequence.</p>
  102. *
  103. * @return the random long
  104. */
  105. public static long nextLong() {
  106. return nextLong(JVM_RANDOM);
  107. }
  108. public static long nextLong(Random rnd) {
  109. return rnd.nextLong();
  110. }
  111. /**
  112. * <p>Returns the next pseudorandom, uniformly distributed boolean value
  113. * from the Math.random() sequence.</p>
  114. *
  115. * @return the random boolean
  116. */
  117. public static boolean nextBoolean() {
  118. return nextBoolean(JVM_RANDOM);
  119. }
  120. public static boolean nextBoolean(Random rnd) {
  121. return rnd.nextBoolean();
  122. }
  123. /**
  124. * <p>Returns the next pseudorandom, uniformly distributed float value
  125. * between <code>0.0</code> and <code>1.0</code> from the Math.random()
  126. * sequence.</p>
  127. *
  128. * @return the random float
  129. */
  130. public static float nextFloat() {
  131. return nextFloat(JVM_RANDOM);
  132. }
  133. public static float nextFloat(Random rnd) {
  134. return rnd.nextFloat();
  135. }
  136. /**
  137. * <p>Synonymous to the Math.random() call.</p>
  138. *
  139. * @return the random double
  140. */
  141. public static double nextDouble() {
  142. return nextDouble(JVM_RANDOM);
  143. }
  144. public static double nextDouble(Random rnd) {
  145. return rnd.nextDouble();
  146. }
  147. }