Allow other formats when binding parameters

[Nicolas Leroux]

In case of a resource url, users can bind define binding on date.

/document/${documentDate} ie /document/01-12-2009/ (documentDate might be the Id)

However, currently we cannot specified the date format and we cannot retrieve the date format according to the locale:
the URL of any resources should not change depending of the locale.

http://groups.google.com/group/play-framework/browse_thread/thread/cb81fb4941a66e52

Add a new annotation that allows to specify the date format: @As("dd-MM-yyyy")

for example:

public static show(@As("dd-mm-yyyy") Date date) {
    ...
}

Note that the same kind of annotation could be used in another use case:

/mailboxes/{<.*>folderNames}/ -> /mailboxes/2009/june/

and then

public static show(@Separator("/") List<String> mailboxes) {
    ...
}

or

/books/{languages}/ -> /books/fr,ja,de/

public static show(@Separator(",") List<String> mailboxes) {
    ...
}

This is basically the same idea, and thus means that the mechanism must be flexible.