[jira] [Commented] (CODEC-141) Generics warnings for StringEncoderComparator

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

    [ https://issues.apache.org/jira/browse/CODEC-141?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13625584#comment-13625584 ] 

Sebb commented on CODEC-141:
----------------------------

Agreed it should ideally implement Comparator<String>.

Unfortunately it's not possible to do so without breaking binary compat., as it's not possible to provide both

public int compare(String, String) // needed to implement Comparator<String>
and
public int compare(Object, Object) // needed to ensure binary compat.

The compiler reports a name clash, as they have the same erasure.

This problem arises in part because StringEncoder extends Encoder.

                
> Generics warnings for StringEncoderComparator
> ---------------------------------------------
>
>                 Key: CODEC-141
>                 URL: https://issues.apache.org/jira/browse/CODEC-141
>             Project: Commons Codec
>          Issue Type: Bug
>            Reporter: Sebb
>         Attachments: CODEC-141.patch
>
>
> The StringEncoderComparator class currently extends the raw type Comparator.
> I think it should extend Comparator<Object>, as it implements compare(Object, Object).
> Although it is documented as being a String comparator, some StringEncoder implementations also support other types such as byte[].
> Secondly, its compare() method currently casts the stringEncoder.encode() results to Comparable.
> This might as well be String, as that is what a StringEncoder is supposed to do.
> If a class cast exception occurs, then this is a bug in the provided StringEncoder (and casting to Comparable would likely also fail).

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