[RNG-115] JDKRandom to allow restore state when saved from a different instance

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Implemented
• Affects Version/s: 1.2
• Fix Version/s: 1.3
• Component/s: core
• Assignee: Alex Herbert
• Reporter: Alex Herbert
• Created: 02/Sep/19 20:19
• Updated: 11/Nov/19 14:25
• Resolved: 03/Sep/19 08:49

Description

Currently the size of the serialized state of the java.util.Random used by JDKRandom is saved to the instance when the state is saved. Thus the state cannot be used to restore a different instance of the same class. This breaks the contract of the RestorableUniformRandomProvider as the state should be applicable to a different instance of the same class.

Fix this test to work:

@Test
public void testRestoreToNewInstance()  {
    final long seed = 8796746234L;
    final JDKRandom rng1 = new JDKRandom(seed);
    final JDKRandom rng2 = new JDKRandom(seed + 1);

    final RandomProviderState state = rng1.saveState();
    rng2.restoreState(state);

    final int numRepeats = 1000;
    for (int r = 0; r < numRepeats; r++) {
        Assert.assertEquals(r + " nextInt", rng1.nextInt(), rng2.nextInt());
    }
}

Issue Links

• links to: GitHub Pull Request #65