Why don't you declare your ClassA as a service too ? This way you could
inject the ServiceClassB into it without any change on ClassA.
Michael Bernagou wrote:
Sorry, I'm trying to understand enough well to develop my application
correctly.
So, imagine I have 2 classes ClassA and ClassB from 2 differents layers.
With the IoC in ClassA I should have just a member named ServiceClassB sab
with its getter and setter. ServiceClassB is the interface ClassB
implements.
Then the IoC should have the role to create the ClassB instance and call
classA.setServiceClassB(classBInstance). But, today in my MVC I have to do
that in ClassA :
public class ClassA {
@Inject
ServiceClassB scb;
String onSuccess() {
User user = scb.getAuthenticatedUser(...);
...
}
}
is THE way to use the IoC? This is an example for pages. I think it's ok but
what about this second example, out of pages.
So I need to create a ServiceFactory class.
public class ServiceFactory {
private ServiceClassB scb;
private static ServiceFactory instance;
static {
instance = new ServiceFactory();
}
public static ServiceFactory getInstance() {
return instance;
}
private ServiceFactory() {
scb = new ClassB();
}
public ServiceClassB getSab() {
return scb;
}
}
In a ClassA (not anymore a Tapestry page) I have to do that :
public class ClassA {
private ServiceClassB sab;
public ServiceClassB getSab() { return sab; }
public void setSab(ServiceClassB sab) { this.sab = sab; }
public String aMethod() {
sab = ServiceFactory.getInstance().getUserService();
User user = sab.getAuthenticatedUser(...);
...
}
}
I think this is not IoC. It's just management of services. So my goal is to
make that IoC and "something" have to call setSab for me, or maybe it's
should be the role of the ServiceFactory?
Regarding what Hugo explained to me, (thanks a lot for your time!) one of
the way is this :
public class UserModule {
public static ServiceClassB build(ServiceUserDao userDao){
ClassB cb = new ClassB(userDao);
return cb;
}
public static ServiceUserDao build() {
UserDao dao = new UserDao();
return dao;
}
}
But I still don't know how to implement ClassA to get my ServiceClassB
instance provided by the IoC. I cannot call the Module without creating a
strong link between ClassA and the IoC, or maybe I have to create this
link?? In my mind, nothing have to call the IoC since it's the IoC who
should call the classes. So I have to say to the IoC which class need it and
for now I just know how to tell the IoC which Services I have and the
dependencies they have.
Or maybe, I'm completely wrong, lol, and in fact the role of IoC is just to
expose services to make them available to the all application and I have in
ClassA to call explicitely the services via their builder in the module and
use them via their interface!
2007/12/17, Hugo Palma <[EMAIL PROTECTED]>:
Ok, as you can see in the tapestry-ioc documentation there are three
ways of injecting dependencies into services. Only one of them is
actually intrusive, the "As parameters to the service implementation
class' constructor (for autobuilt services)" one. If you use this way
then you will need to use the Inject annotation in your service
implementation class which will create the dependency you don't want.
So, this leaves you with the other two choices. The "As parameters to
the service builder method" way has an example right in the beginning of
the "Injecting Dependencies" sections of the docs. This way your service
class can be completely independent of your IoC container. All the
injection stuff is done in the module builder class. All you have to do
is declare the dependencies in your service build method in the module
builder and use the service class setters to set it's dependencies.
Finally, you can use the "As parameters passed to the constructor of the
service's module builder (cached inside instance variables)" way. This
in not intrusive also because, again, all the injection stuff is done in
the module builder. Only this time instead of the dependencies being
injected as parameters in the build method they are injected in you
module builder class constructor.
Hope this helps...
Michael Bernagou wrote:
Hi Hugo,
It is exactly that and I didn't understand how to do that. Whatever I
test,
it works but it is intrusive.
I re-read the documentation about tapestry-ioc and I still not
understand
how to do that. I need an example of webapp with 3 layers around the ioc
to
see how tapestry-ioc gives the services instance to the layers.
@Thiago, I read this part but I don't know enought Spring to decide if
tapestry-ioc is really better than Spring. I'm not sure "better" is the
word. I would prefer "more adapt for Tapestry webapp" but it's just my
feelling. Just to argue a little more, if it is really "better", why the
way
to use service injection is different between ioc - MVC and ioc - DAO or
ioc
- WS (example, declare a Logger in these all 3 layers and compare the
howto)? Learning a way to do the same thing for each layer is not
something
"better".
I'm quite sure it can be "better" than Spring but for some developper,
XML
is better than Pojo... just a point of view ;o)
For now, I want to try to use Tapestry-ioc because I think again it is
more
adapt to my needs
2007/12/14, Hugo Palma <[EMAIL PROTECTED]>:
mmmmm, i think there's something missing here....
If i'm understanding correctly you want tapestry-ioc to manage all your
services (either presentation stuf, db stuff, etc) and you don't want
it
to be intrusive. You don't want to reference any tapestry-ioc API
inside
you service classes. Does that describe the problem ?
If so, tapestry-ioc can solve your problem really easily.
Michael Bernagou wrote:
So I have to call the current Registry (or to manage it myself) and
call
the
myRegistry.getService(MyService.class);
Hum, I think it's not ioc anymore if I have to setup my containers
(Axis2,
Hibernate) to call the tapestry-ioc or I have to create a sort of
"middle
layer" between the layer and the tapestry-ioc, and then my classes
have
to
call this middleLayer... hum...
How do you do yourself? Webapp have usually more than just a MVC
layer.
Are
you using the tapestry-ioc only for the MVC layer?
Its seems to me strange for one class having to use @Inject Logger
log;
and
for another class Logger log = Logger.getLogger(
ApplicationDaoImpl.class.getName());
2 ways to get the logger in the same application for the same target
log
file... Maybe tapestry-ioc should be extended to take care also to the
other
layers.
Maybe I'm totally wrong ;o) so, how should it be coded to respect ioc
pattern between tapestr-ioc and other layers such as Axis2 and
Hibernate3
(for T5 we know ;o) )
Thanks
2007/12/14, Michael Bernagou <[EMAIL PROTECTED]>:
Ok I'm going to investigate about that Registry.
So, what's the interrest to use tapestry-ioc instead of Spring ioc?
If
I
need my ioc to provide all the services I need, I cannot use
tapestry-ioc
unless I need my other layers to call explicitely the ioc which is
not
recommended when you want independant layers working together.
@Hugo, ok I'm going to reread again this part.
2007/12/14, Kristian Marinkovic <[EMAIL PROTECTED] >:
hi michael,
@Inject only works in Tapestry pages and components (and mixins).
By default Tapestry will use the field type as an id and lookup the
corresponding ioc service.
I assume your Web Service Container was not started by the ioc
container so it runs outside its control. Therefore you have to
first
obtain an ioc Registry first and then ask it explicitly for the
service
you want to call. The builder methods are not meant to be called
except by the container :)
g,
kris
"Michael Bernagou" < [EMAIL PROTECTED]>
14.12.2007 10:51
Bitte antworten an
"Tapestry users" <users@tapestry.apache.org >
An
"Tapestry users" <users@tapestry.apache.org>
Kopie
Thema
IoC global question
Hi,
I have a sort of general question about tapestry-ioc. In fact, I
would
like
it to manage all the services of my webapp. In theory it should be
the
case,
shouldn't be?
So to provides services to my MVC, no problem the syntax @Inject
MyService
_myService; work perfectly. But, to provide services the same way
for
my
Dao
it's different. The same syntax doesn't provide any instance.
I used the tapestry-hibernate and declare my dao as services :
import org.hibernate.Session;
public static UserDao buildUserDao(@InjectService("Session")
Session
session) {
return new UserDaoImpl(session);
}
public static UserService
buildUserService(@InjectService("UserDao")
UserDao dao) {
return new UserServiceImpl(dao);
}
So my implementation can work. But to use the service, all the
callers
have
to know a session object!
Ok, if my caller is a web service, and this web service want to call
the
UserService, @Inject UserService _userService; DOES NOT work and
_userService is null! So I have to call explicitely the builder of
my
service FROM the web service... If I do that, I bypass the IoC
purpose
because I link it directly :
UserService us = AppModule.buildUserService ( ... and then I have a
problem!
buildUserService need a UserDao, but my web service doesn't care
about
knowing any kind of dao!
So, I should be able to use @Inject MyService _myService; anywhere
in
my
project and the tapestry-ioc should be able to give instance to all
the
class...
Did I (probably) missed something?
--
Michael Bernagou
Java Developper
--
Michael Bernagou
Java Developper
