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