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From "Til Boerner (JIRA)" <>
Subject [jira] [Created] (VALIDATOR-308) Logical errors in util.Flags
Date Mon, 30 Jul 2012 21:07:34 GMT
Til Boerner created VALIDATOR-308:

             Summary: Logical errors in util.Flags
                 Key: VALIDATOR-308
             Project: Commons Validator
          Issue Type: Bug
          Components: Framework
    Affects Versions: 1.4.0 Release
         Environment: any; flawed logic is independent of environment
            Reporter: Til Boerner
            Priority: Minor

I just came across Validator.util.Flags while trying to avoid writing my own flag class. Two
errors caught my eye:

1) Java uses two's complement representation for its signed primitives. Two important consequences:
the highest order bit signifies a negative number; Long.MAX_VALUE is not the value that has
all bits set. This affects flag.isOn(long) and flag.turnAllOn() .

2) If I understand correctly, flag.isOn(long) is supposed to test if flag has ALL bits set
which are also set in the long argument. Comparing against 0 is the wrong way to do this,
even when correcting for the mistake from 1). By comparing against 0, the test merely checks
if the two values have ANY bits in common, which is not what the method's documentation seems
to imply.

These cases don't seem to get much use, otherwise this would be a serious problem. (And already
be fixed, is my guess.) But still, it is bad enough to completely ruin the day of anyone who
happens to rely on these features, and the poor soul would rightly curse anyone who allowed
them to persist in this wretched state.

After submitting this, I can hopefully attach the patch I made. Actually there are two separate
patches: one for the test, which illustrates the problems, and a very simple one for the Flags
implementation, which fixes them.

Cheerio! :)

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