[jira] Updated: (JCR-687) UUID compareTo and hashCode

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

     [ http://issues.apache.org/jira/browse/JCR-687?page=all ]

Thomas Mueller updated JCR-687:
-------------------------------

    Attachment: uuid.txt

Corrected compareTo and simplified hashCode implementations.

> UUID compareTo and hashCode
> ---------------------------
>
>                 Key: JCR-687
>                 URL: http://issues.apache.org/jira/browse/JCR-687
>             Project: Jackrabbit
>          Issue Type: Bug
>          Components: core
>            Reporter: Thomas Mueller
>            Priority: Minor
>         Attachments: uuid.txt
>
>
> The current UUID.compareTo implementation is not correct. Usually, 'equals' is used so this is not a big problem, but I need to create an ordered list of UUIDs and for this I need compareTo. The current implementation is based on subtraction, but this doesn't always work. Example:
> //long a = 10, b = 20, c = 0;
> long a = Long.MAX_VALUE, b = Long.MIN_VALUE, c = 0;
> System.out.println((a - b) < 0 ? "a < b" : "a >= b");
> System.out.println((c - a) < 0 ? "c < a" : "c >= a");
> System.out.println((b - c) < 0 ? "b < c" : "b >= c");
> The hashCode implementation is OK, but the multiplication is not required.

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