Howdy,
Scala is a static language, so the class for casting must be known at
compile time. It's not possible to construct a String at runtime and cast
an object into a class represented by that String.
However, casting to a known class is easy in Scala... and it's done
primarily using pattern matching. The following code:
def foo(in: Any) = in match {
case mm: MetaMapper[_] =>
mm.findAll.map(
(m: Mapper[_]) =>
m.asJs
)
case _ =>
}
Does what I think you want. It takes an incoming instance, in and matches
it against being an instance of MetaMapper[_]. This means its some type of
MetaMapper (we don't know or care what the type parameter is). If it is a
MetaMapper, it's assigned to the mm variable. We can then call findAll on
that variable and we have a bunch of Mapper[_] instances. Note that I
explicitly called out the type of m in the function, but that line could be
re-written mm.findAll.map(m => m.asJs) because the compiler infers the type
of m.
Does this help?
Thanks,
David
On Thu, Apr 9, 2009 at 3:55 AM, Amit Kumar Verma <cdac.a...@gmail.com>wrote:
>
> Hi All,
>
> I am trying to type cast an scala object to its mapper object
>
> 1 def getJSONString(anyObject :Object):NodeSeq = {
>
> 2 var obj = anyObject.asInstanceOf[anyObject.getClass
> ().getName()];
>
> 3 obj.findAll.map(userdetails => {
> // some code will go here
> }
> Text("any string")
> }
>
>
> but i am getting erroe as "expected [ but found (" on line 2.
>
> please help me to typecast the object to its mapper object.
>
> Thanks
> Amit Kumar Verma
>
> >
>
--
Lift, the simply functional web framework http://liftweb.net
Beginning Scala http://www.apress.com/book/view/1430219890
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