You could do it via reflection:
import java.lang.reflect.*;
public class ConverterService {
public void convert(Object o) throws Exception{
for (Method m : getClass().getDeclaredMethods()) {
if (m.getName().equals("handle")) {
Class<?> paramType = m.getParameterTypes()[0];
if (paramType.isInstance(o)) {
m.invoke(this, o);
}
}
}
}
public void handle(Foo foo) {
System.out.println("Converting foo");
}
public void handle(Bar bar) {
System.out.println("Converting bar");
}
public void handle(Baz baz) {
System.out.println("Converting baz");
}
public static void main(String [] args) throws Exception {
ConverterService c = new ConverterService();
c.convert(new Foo());
c.convert(new Bar());
c.convert(new Baz());
}
}
class Foo { }
class Bar { }
class Baz { }
On Nov 28, 2007 4:31 PM, Jason Terhune <[EMAIL PROTECTED]> wrote:
> Paul J. Lucas <pauljlucas <at> mac.com> writes:
>
> > On Nov 26, 2007, at 2:33 AM, Jerome Louvel wrote:
> >
> > > Your suggestion regarding the map of ConverterService is
> > > interesting. However, how would you handle the reverse conversion
> > > (from Representation to Object) ?
> >
> > Also using a map. For both conversion directions, you allow for the
> > possibility of subclasses, e.g.:
> >
> > public class ConverterServiceMap extends ConverterService {
> > // ...
> >
> > public Object toObject( Representation rep ) {
> > for ( Class c = rep.getClass(); c != Object.class;
> > c = c.getSuperclass() ) {
> > final ConverterService cs = m_toObjMap.get( c );
> > if ( cs != null )
> > return cs.toObject( rep );
> > }
> > return super.toObject( rep );
> > }
> > }
>
> I haven't actually tried this, but couldn't you just overload the
> toObject()
> and toRepresentation() methods? Doesn't Java do the work of choosing the
> method with the most specific argument?
>
> For example:
> public class ConverterService extends ConverterService {
> public Foo toObject(FooRepresentation fr);
>
> public FooRepresentation toRepresentation(Foo f);
> }
>
>
