OpenJDK / jdk / hs
changeset 45269:abfa63124042
8180805: move RandomFactory to the top level testlibrary
Reviewed-by: bpb, rriggs
author | iignatyev |
---|---|
date | Tue, 30 May 2017 21:14:02 -0700 |
parents | c658e313ee1f |
children | 81a039ba9344 |
files | test/lib/jdk/test/lib/RandomFactory.java |
diffstat | 1 files changed, 103 insertions(+), 0 deletions(-) [+] |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/test/lib/jdk/test/lib/RandomFactory.java Tue May 30 21:14:02 2017 -0700 @@ -0,0 +1,103 @@ +/* + * Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This code is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. + * + * This code is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * version 2 for more details (a copy is included in the LICENSE file that + * accompanied this code). + * + * You should have received a copy of the GNU General Public License version + * 2 along with this work; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA + * or visit www.oracle.com if you need additional information or have any + * questions. + */ + +package jdk.test.lib; + +import java.util.Random; +import java.util.SplittableRandom; + +/** + * Factory class which generates and prints to STDOUT a long-valued seed + * for use in initializing a PRNG. An instance of {@code Random} or + * {@code SplittableRandom} may likewise be obtained. + */ +public class RandomFactory { + /** + * Attempt to obtain the seed from the value of the "seed" property. + * @return The seed or {@code null} if the "seed" property was not set or + * could not be parsed. + */ + private static Long getSystemSeed() { + Long seed = null; + try { + // note that Long.valueOf(null) also throws a + // NumberFormatException so if the property is undefined this + // will still work correctly + seed = Long.valueOf(System.getProperty("seed")); + } catch (NumberFormatException e) { + // do nothing: seed is still null + } + + return seed; + } + + /** + * Obtain a seed from an independent PRNG. + * + * @return A random seed. + */ + private static long getRandomSeed() { + return new Random().nextLong(); + } + + /** + * Obtain and print to STDOUT a seed appropriate for initializing a PRNG. + * If the system property "seed" is set and has value which may be correctly + * parsed it is used, otherwise a seed is generated using an independent + * PRNG. + * + * @return The seed. + */ + public static long getSeed() { + Long seed = getSystemSeed(); + if (seed == null) { + seed = getRandomSeed(); + } + System.out.println("Seed from RandomFactory = "+seed+"L"); + return seed; + } + + /** + * Obtain and print to STDOUT a seed and use it to initialize a new + * {@code Random} instance which is returned. If the system + * property "seed" is set and has value which may be correctly parsed it + * is used, otherwise a seed is generated using an independent PRNG. + * + * @return The {@code Random} instance. + */ + public static Random getRandom() { + return new Random(getSeed()); + } + + /** + * Obtain and print to STDOUT a seed and use it to initialize a new + * {@code SplittableRandom} instance which is returned. If the system + * property "seed" is set and has value which may be correctly parsed it + * is used, otherwise a seed is generated using an independent PRNG. + * + * @return The {@code SplittableRandom} instance. + */ + public static SplittableRandom getSplittableRandom() { + return new SplittableRandom(getSeed()); + } +}