| /* ==================================================================== |
| * The Apache Software License, Version 1.1 |
| * |
| * Copyright (c) 2002 The Apache Software Foundation. All rights |
| * reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * 3. The end-user documentation included with the redistribution, if |
| * any, must include the following acknowlegement: |
| * "This product includes software developed by the |
| * Apache Software Foundation (http://www.apache.org/)." |
| * Alternately, this acknowlegement may appear in the software itself, |
| * if and wherever such third-party acknowlegements normally appear. |
| * |
| * 4. The names "The Jakarta Project", "Commons", and "Apache Software |
| * Foundation" must not be used to endorse or promote products derived |
| * from this software without prior written permission. For written |
| * permission, please contact apache@apache.org. |
| * |
| * 5. Products derived from this software may not be called "Apache" |
| * nor may "Apache" appear in their names without prior written |
| * permission of the Apache Software Foundation. |
| * |
| * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED |
| * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
| * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR |
| * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF |
| * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
| * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
| * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
| * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| * SUCH DAMAGE. |
| * ==================================================================== |
| * |
| * This software consists of voluntary contributions made by many |
| * individuals on behalf of the Apache Software Foundation. For more |
| * information on the Apache Software Foundation, please see |
| * <http://www.apache.org/>. |
| */ |
| package org.apache.commons.lang.math; |
| |
| import java.util.Random; |
| |
| /** |
| * <p><code>JVMRandom</code> is a wrapper that supports all possible |
| * Random methods via the {@link java.lang.Math#random()} method |
| * and its system-wide {@link Random} object.</p> |
| * |
| * @author Henri Yandell |
| * @since 2.0 |
| * @version $Id: JVMRandom.java,v 1.7 2003/07/14 22:25:05 bayard Exp $ |
| */ |
| public final class JVMRandom extends Random { |
| |
| /** |
| * Ensures that only the constructor can call reseed. |
| */ |
| private boolean constructed = false; |
| |
| public JVMRandom() { |
| this.constructed = true; |
| } |
| |
| /** |
| * Unsupported in 2.0. |
| */ |
| public synchronized void setSeed(long seed) { |
| if (this.constructed) { |
| throw new UnsupportedOperationException(); |
| } |
| } |
| |
| /** |
| * Unsupported in 2.0. |
| */ |
| public synchronized double nextGaussian() { |
| throw new UnsupportedOperationException(); |
| } |
| |
| /** |
| * Unsupported in 2.0. |
| */ |
| public void nextBytes(byte[] byteArray) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| /** |
| * <p>Returns the next pseudorandom, uniformly distributed int value |
| * from the Math.random() sequence.</p> |
| * |
| * @return the random int |
| */ |
| public int nextInt() { |
| return nextInt(Integer.MAX_VALUE); |
| } |
| /** |
| * <p>Returns a pseudorandom, uniformly distributed int value between |
| * <code>0</code> (inclusive) and the specified value (exclusive), from |
| * the Math.random() sequence.</p> |
| * |
| * @param n the specified exclusive max-value |
| * @return the random int |
| * @throws IllegalArgumentException when <code>n <= 0</code> |
| */ |
| public int nextInt(int n) { |
| if (n <= 0) { |
| throw new IllegalArgumentException( |
| "Upper bound for nextInt must be positive" |
| ); |
| } |
| // TODO: check this cannot return 'n' |
| return (int)(Math.random() * n); |
| } |
| /** |
| * <p>Returns the next pseudorandom, uniformly distributed long value |
| * from the Math.random() sequence.</p> |
| * @return the random long |
| */ |
| public long nextLong() { |
| // possible loss of precision? |
| return nextLong(Long.MAX_VALUE); |
| } |
| |
| |
| /** |
| * <p>Returns a pseudorandom, uniformly distributed long value between |
| * <code>0</code> (inclusive) and the specified value (exclusive), from |
| * the Math.random() sequence.</p> |
| * |
| * @param n the specified exclusive max-value |
| * @return the random long |
| * @throws IllegalArgumentException when <code>n <= 0</code> |
| */ |
| public static long nextLong(long n) { |
| if (n <= 0) { |
| throw new IllegalArgumentException( |
| "Upper bound for nextInt must be positive" |
| ); |
| } |
| // TODO: check this cannot return 'n' |
| return (long)(Math.random() * n); |
| } |
| |
| /** |
| * <p>Returns the next pseudorandom, uniformly distributed boolean value |
| * from the Math.random() sequence.</p> |
| * |
| * @return the random boolean |
| */ |
| public boolean nextBoolean() { |
| return (Math.random() > 0.5); |
| } |
| /** |
| * <p>Returns the next pseudorandom, uniformly distributed float value |
| * between <code>0.0</code> and <code>1.0</code> from the Math.random() |
| * sequence.</p> |
| * |
| * @return the random float |
| */ |
| public float nextFloat() { |
| return (float)Math.random(); |
| } |
| /** |
| * <p>Synonymous to the Math.random() call.</p> |
| * |
| * @return the random double |
| */ |
| public double nextDouble() { |
| return Math.random(); |
| } |
| |
| } |