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From "Henri Yandell (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (LANG-745) StrLookup API confusing
Date Mon, 21 Oct 2013 19:53:44 GMT

     [ https://issues.apache.org/jira/browse/LANG-745?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Henri Yandell updated LANG-745:
-------------------------------

    Fix Version/s: Patch Needed

> StrLookup API confusing
> -----------------------
>
>                 Key: LANG-745
>                 URL: https://issues.apache.org/jira/browse/LANG-745
>             Project: Commons Lang
>          Issue Type: Bug
>          Components: lang.*
>    Affects Versions: 3.0
>            Reporter: Etienne Neveu
>             Fix For: Patch Needed
>
>
> [bayard: copying this from LANG-564]
> I don't see the point of having a generic type parameter on the StrLookup class, if it's
not used anywhere. No method / field in StrLookup references this type parameter. IntelliJ
IDEA itself reports a warning: "Type parameter 'V' is never used". Moreover, Java generics
are not reified, so there is no reliable way to access the type parameter at runtime (and
I don't see the point of doing that anyway...).
> While the Javadoc tries to clarify the purpose of a StrLookup, the unused type parameter
is still confusing, and the client code has to un-necessarily specify type parameters. For
example, I have to write:
> StrLookup<?> lookup = StrLookup.noneLookup();
> StrLookup<String> lookup2 = StrLookup.systemPropertiesLookup();
> StrLookup<Integer> lookup3 = StrLookup.mapLookup(integerMap);
> instead of
> StrLookup lookup = StrLookup.noneLookup();
> StrLookup lookup2 = StrLookup.systemPropertiesLookup();
> StrLookup lookup3 = StrLookup.mapLookup(integerMap);
> My best guess is that this type parameter was added when commons-lang was generified,
because StringLookup.mapLookup() takes a generified Map. Doing this is not really needed,
though: we could remove the <V> type parameter everywhere, and replace the StrLookup.mapLookup()'s
Map<String, V> with a Map<String, ?> (which is the same as Map<String, ? extends
Object>, but shorter).
> I guess it's too late to change this now, due to backward compatibility... But I thought
I'd comment just in case it's still possible.



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