Name: jl125535 Date: 03/19/2004


A DESCRIPTION OF THE REQUEST :
You cannot create a new instance of a generic type. Nor is there any way to obtain the Class of that generic. I would like to be able to perform the following function:

class MyClass<T>
{
    T enclosedInstance;

    public MyClass()
     {
         enclosedInstance = T.class.newInstance(); // like Object.class
     }
}

The usage code will allow me to create an instance without too much fuss like this:

MyClass<DefaultMyInterface> system = new MyClass<DefaultMyInterface>();
system.enclosedInstance.doSomething();


JUSTIFICATION :
When you have a parameterized interface that solves some problems, using that parameterized interface can be rather an inconvenience. For example, in my code I have an interface like this:

interface Profile<VALIDATOR extends ComponentValidator,
                               FACTORY extends ComponentFacotry,
                               ASSEMBLER extends Assembler>
{
    VALIDATOR getValidator();
    FACTORY getFactory();
    ASSEMBLER getAssembler();
}

When I have a definition class, it is very simple:

class DefaultProfile impelments
     Profile<TypeManager,TypeManager,DefaultAssembler>
{
    // ... the implementation
}

That way I can create a new container for my profile without having to do it in two steps. Right now I have to do this:

DefaultProfile profile = new DefaultProfile();
Container container = new Container(profile);

profile.getAssembler().invokeMethodNotInInterface();

The important thing is that I want to separate how the container uses the profile from the way the client uses it. I would like to simplify the useage to the following:

Container<DefaultProfile> container = new Container<DefaultProfile>();
container.getProfile().getAssembler().invokeMethodNotInInterface();

Make it more compact.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
T.class.newInstance() operates the same way that Object.class.newInstance() operates.
ACTUAL -
Compile error
(Incident Review ID: 244080)
======================================================================