[jira] [Created] (FUNCTOR-8) [PATCH] Possible NPE in TransformedGenerator if getWrappedGenerator() is overridden to return null

[Bruno P. Kinoshita (Created) (JIRA)]

[PATCH] Possible NPE in TransformedGenerator if getWrappedGenerator() is 
overridden to return null
--------------------------------------------------------------------------------------------------

                 Key: FUNCTOR-8
                 URL: https://issues.apache.org/jira/browse/FUNCTOR-8
             Project: Commons Functor
          Issue Type: Bug
         Environment: ubuntu 11.10, sun-jdk-6, eclipse galileo
            Reporter: Bruno P. Kinoshita
         Attachments: FUNCTOR-8.patch

If we override getWrappedGenerator method in TransformedGenerator to return 
null, it may result in a NullPointerException if hashCode is called.

Attached the patch for it, and below a snippet of code to reproduce this issue.

    TransformedGenerator<Integer, Integer> t = new 
TransformedGenerator<Integer, Integer>(
        new IntegerRange(1, 10), new UnaryFunction<Integer, Integer>() {
                public Integer evaluate(Integer obj) {
                        return obj += 1;
                }
        }) {
        @Override
            protected Generator<? extends Integer> getWrappedGenerator() {
                return null;
        }
    };

    TransformedGenerator<Integer, Integer> t2 = new 
TransformedGenerator<Integer, Integer>(
        new IntegerRange(1, 10), new UnaryFunction<Integer, Integer>() {
                public Integer evaluate(Integer obj) {
                        return obj -= 1;
                }
        });

    System.out.println(t.equals(t2));

    System.out.println(t.hashCode() == t2.hashCode()); // NPE

Cheers,
Bruno P. Kinoshita

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