Question

I’d like to use UUID as action parameters. However, unless I use .toString() on the UUID objects when generating the action URL’s, Play seems to serialize the object differently; Something like this: referenceId.sequence=-1&referenceId.hashCode=1728064460&referenceId.version=-1&referenceId.variant=-1&referenceId.timestamp=-1&referenceId.node=-1

However, using toString “works”, but when I redirect from one action to another by simply invoking the method directly, there’s no way I can call toString, as the method expects a UUID. Therefore it gives me the representation shown above.

Is there any way I can intersect the serialization of a certain type?

Answer 1

I found a way to do this, but right now it means hacking a part of the frameworks code itself.

What you basically need is a TypeBinder for binding the value from the String to the UUID
and a small code change in
play/framework/src/play/data/binding/Unbinder.java

    if (!isAsAnnotation) {
        // We want to use that one so when redirecting it looks ok. We could as well use the DateBinder.ISO8601 but the url looks terrible
        if (Calendar.class.isAssignableFrom(src.getClass())) {
            result.put(name, new SimpleDateFormat(I18N.getDateFormat()).format(((Calendar) src).getTime()));
        } else {
            result.put(name, new SimpleDateFormat(I18N.getDateFormat()).format((Date) src));
        }
    }
}
//here's the changed code
else if (UUID.class.isAssignableFrom(src.getClass()))
{
   result.put(name, src.toString());
}
else {
// this code is responsible for the behavior you're seeing right now
        Field[] fields = src.getClass().getDeclaredFields(); 
        for (Field field : fields) {

            if ((field.getModifiers() & BeanWrapper.notwritableField) != 0) {
                // skip fields that cannot be bound by BeanWrapper
                continue;
            }

I’m working with the framework authors on a fix for this. will come back later with results.

if you need this urgently, apply the change to the code yourself and rebuild the framework by issuing
ant
in the playframework/framework
directory.