jdk/test/java/math/RandomSeed.java
changeset 30060 4139787319e7
parent 30059 3efcc9d8fe88
parent 30058 73cc6c3996eb
child 30062 1d5767efe1fd
equal deleted inserted replaced
30059:3efcc9d8fe88 30060:4139787319e7
     1 /*
       
     2  * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
       
     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
       
     4  *
       
     5  * This code is free software; you can redistribute it and/or modify it
       
     6  * under the terms of the GNU General Public License version 2 only, as
       
     7  * published by the Free Software Foundation.
       
     8  *
       
     9  * This code is distributed in the hope that it will be useful, but WITHOUT
       
    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
       
    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
       
    12  * version 2 for more details (a copy is included in the LICENSE file that
       
    13  * accompanied this code).
       
    14  *
       
    15  * You should have received a copy of the GNU General Public License version
       
    16  * 2 along with this work; if not, write to the Free Software Foundation,
       
    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
       
    18  *
       
    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
       
    20  * or visit www.oracle.com if you need additional information or have any
       
    21  * questions.
       
    22  */
       
    23 
       
    24 import java.util.Random;
       
    25 import java.util.SplittableRandom;
       
    26 
       
    27 public class RandomSeed {
       
    28     private long seed = 0L;
       
    29     private Random rnd = null;
       
    30     private SplittableRandom srnd = null;
       
    31 
       
    32     public RandomSeed(boolean isSplittableRandom) {
       
    33         init(isSplittableRandom);
       
    34     }
       
    35 
       
    36     private void init(boolean isSplittableRandom) {
       
    37         // obtain seed from environment if supplied
       
    38         boolean isSeedProvided = false;
       
    39         try {
       
    40             // note that Long.valueOf(null) also throws a NumberFormatException
       
    41             // so if the property is undefined this will still work correctly
       
    42             seed = Long.valueOf(System.getProperty("seed"));
       
    43             isSeedProvided = true;
       
    44         } catch (NumberFormatException e) {
       
    45             // do nothing: isSeedProvided is already false
       
    46         }
       
    47 
       
    48         // if no seed from environment, create a fresh one
       
    49         Random tmpRnd = null;
       
    50         if (!isSeedProvided) {
       
    51             tmpRnd = new Random();
       
    52             seed = tmpRnd.nextLong();
       
    53         }
       
    54 
       
    55         // create the PRNG
       
    56         if (isSplittableRandom) {
       
    57             srnd = new SplittableRandom(seed);
       
    58         } else {
       
    59             rnd = tmpRnd != null ? tmpRnd : new Random();
       
    60             rnd.setSeed(seed);
       
    61         }
       
    62     }
       
    63 
       
    64     public Random getRandom() {
       
    65         if (rnd == null) {
       
    66             throw new IllegalStateException("Variable of type Random not initialized");
       
    67         }
       
    68         return rnd;
       
    69     }
       
    70 
       
    71     public SplittableRandom getSplittableRandom() {
       
    72         if (srnd == null) {
       
    73             throw new IllegalStateException("Variable of type SplittableRandom not initialized");
       
    74         }
       
    75         return srnd;
       
    76     }
       
    77 
       
    78     public long getSeed() {
       
    79         return seed;
       
    80     }
       
    81 }