best way to create native javascript date from Java with Rhino

[Barnabas Wolf]

What is the best way to create a JavaScript Date object from Java?
Rhino wraps java.util.Date's using NativeJavaObject; it does not
convert them to NativeDate. I am currently using a workaround in a
WrapFactory:

if (val instanceof java.util.Date) {
long time=((java.util.Date) val).getTime();
return cx.evaluateString(
scope, "new Date(" + time + ");",
"date conversion", 1, null)
}

Is there a better way to do this? (More efficient or more elegant
way?)

Is there a specific reason Rhino is not able to convert Dates into
native types, like it can with Numbers and Strings?

Thanks,
Barnabas

[Igor Bukanov]

Post by Barnabas Wolf
What is the best way to create a JavaScript Date object from Java?
Rhino wraps java.util.Date's using NativeJavaObject; it does not
convert them to NativeDate. I am currently using a workaround in a
if (val instanceof java.util.Date) {
long time=((java.util.Date) val).getTime();
return cx.evaluateString(
scope, "new Date(" + time + ");",
"date conversion", 1, null)
}
Is there a better way to do this? (More efficient or more elegant
way?)

To call a constructor defined in the given scope, use
Context.toObject(),
http://mozilla.org/rhino/apidocs/org/mozilla/javascript/Context.html#newObject(org.mozilla.javascript.Scriptable,%20java.lang.String,%20java.lang.Object[])

So in your case you will have:

if (val instanceof java.util.Date) {
long time=((java.util.Date) val).getTime();
return cx.newObject(scope, "Date", new Object[] { new Double(time) });
}

Post by Barnabas Wolf
Is there a specific reason Rhino is not able to convert Dates into
native types, like it can with Numbers and Strings?

Rhino does not by default converts Java Number and String objects to
corresponding primitive types. Instead it wraps them to a special script
objects in the same way as it expose any other JavaObject to scripts via
LiveConnect, it only converts primitive Java values to corresponding
script values. To override this, you need to provide a custom
WrapHandler (WrapFactory in the forthcoming Rhino 1.5R4).

java.util.Date and Date objects in JavaScript are sufficiently different
not only by their API, but also by internal presentation. In particular,
Date in Script can hold NaN value while java.util.Date can not. For
these reasons it is best to left to applications to decide how to
convert one to another.

Regards, Igor