[jira] [Updated] (MATH-942) DiscreteDistribution.sample(int) may throw an exception if first element of singletons of sub-class type

["Piotr Wydrych (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/MATH-942?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Piotr Wydrych updated MATH-942:
-------------------------------

    Attachment: DiscreteDistribution.java.patch
    
> DiscreteDistribution.sample(int) may throw an exception if first element of singletons of sub-class type
> --------------------------------------------------------------------------------------------------------
>
>                 Key: MATH-942
>                 URL: https://issues.apache.org/jira/browse/MATH-942
>             Project: Commons Math
>          Issue Type: Bug
>            Reporter: Piotr Wydrych
>         Attachments: DiscreteDistribution.java.patch
>
>
> Creating an array with {{Array.newInstance(singletons.get(0).getClass(), sampleSize)}} in DiscreteDistribution.sample(int) is risky. An exception will be thrown if:
> * {{singleons.get(0)}} is of type T1, an sub-class of T, and
> * DiscreteDistribution.sample() returns an object which is of type T, but not of type T1.
> To reproduce:
> {code}
> List<Pair<Object,Double>> list = new ArrayList<Pair<Object, Double>>();
> list.add(new Pair<Object, Double>(new Object() {}, new Double(0)));
> list.add(new Pair<Object, Double>(new Object() {}, new Double(1)));
> new DiscreteDistribution<Object>(list).sample(1);
> {code}
> Attaching a patch.

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