GWT RequestFactory: inheriting interfaces into a RequestContext - gwt

I have my OrganizationRequestContext interface, which works great:
#Service(OrganizationDAO.class)
public interface OrganizationRequestContext extends RequestContext
{
Request<OrganizationProxy> findOrganization(Long id);
InstanceRequest<OrganizationProxy, Void> persist();
InstanceRequest<OrganizationProxy, Void> remove();
}
Now I want to take those last two functions and put them in a PersistentRequestContext of my own design so that I can treat all of my RequestContexts the same in my client code:
public interface PersistableRequestContext<T extends BaseProxy>
{
InstanceRequest<T, Void> persist();
InstanceRequest<T, Void> remove();
}
...
#Service(OrganizationDAO.class)
public interface OrganizationRequestContext extends RequestContext, PersistentRequestContext<OrganizationProxy>
{
Request<OrganizationProxy> findOrganization(Long id);
}
But this fails validation: the server complains that
[ERROR] com.activegrade.shared.data.PersistableRequestContext is not a RequestContext
If I make PersistableRequestContext extend RequestContext, then the server complains that it is not linked to any particular DAO service.
Is there any way to extend a common interface besides RequestContext in my various RequestContext interfaces?

This issue has been fixed in GWT 2.4. Thanks Google!
http://code.google.com/p/google-web-toolkit/issues/detail?id=6035

Related

spring data repository Implenation

I am using Spring DATA JPA and selected #Query annotation for creating queries (instead of using NamedQueries and Queries created from MethodName)
I have a data repository as below
public interface EventRepository extends CrudRepository<Event, Long> {
#Query("select e from Event e where e.name = :eventName)
public List<Event>findEventByName(String eventName );
}
Interface looks good and its enough as per Spring reference doc.
But I need a impl class because I need many other methods in addition to above.
I am facing 2 issues when I create EventRepositoryImpl java implementing EventRepository
Its asking to implement all the methods in EventRepository, findEventByName method is self contained in interface and why I need implement it again in Impl class?
Its asking to implement all the methods in CrudRepository, I know its per OOPS design, But there many methods
So, for these issues can I define my EventRepositoryImpl as abstract,
this seems to be working fine.
But do I need to worry about anything else, when Spring uses a abstract class as a bean.
or is there an elegant way to solve this issue.
Appreciate your help.
You do not have to implement all of these methods neither create an abstract class. Take a look into official documentation.
interface UserRepositoryCustom {
public void someCustomMethod(User user);
}
class UserRepositoryImpl implements UserRepositoryCustom {
public void someCustomMethod(User user) {
// Your custom implementation
}
}
interface UserRepository extends CrudRepository<User, Long>, UserRepositoryCustom {
// Declare query methods here
}

Inconsistent behaviour on a fake(interface vs abstract class) using fakeiteasy

I had following code
public interface IFoo
{
void Execute();
}
public abstract class FooBar: IFoo
{
public void Execute()
{
OnExecute();
}
public abstract void OnExecute();
}
and following test case to test the Execute() method
[Fact]
public void When_execute_method_called_Expect_executionTime_is_set()
{
var sutMethod = A.Fake<FooBar>();
A.CallTo(sutMethod).
Where(x => x.Method.Name == "OnExecute").
Invokes(x => Thread.Sleep(100)));
sutMethod.Execute();
Assert.NotEqual(0, sutMethod.Result.ExecutionTime.Ticks);
}
sutMethod.Execute(); call would go to FooBar.Execute()
later I decided to make the interface into an abstract class
public abstract class IFoo
{
public abstract void Execute();
}
public abstract class FooBar:IFoo
{
public override void Execute()
{
OnExecute();
}
public abstract void OnExecute();
}
Now sutMethod.Execute(); call does not invoke FooBar.Execute()
I thought FakeItEasy would handles interface and abstract classes as equal.What am I missing?
Update
# Blair Conrad provided the reasoning for the behaviour
Is it possible to make minimal changes to the test case to get the original behaviour back?
thanks
The difference is due to the overrideability of the method Execute on FooBar.
FakeItEasy can only override virtual members, abstract members, or interface members.
In your original example, when IFooBar is an interface and FooBar implements it, Execute is a concrete method. It's not virtual, nor is it abstract. Thus FakeItEasy can't intercept calls to it, and the original method is executed.
Once you change IFooBar to an abstract class, you have an abstract IFooBar.Execute, which you override in FooBar. As such, FooBar.Execute is now virtual and can be intercepted by FakeItEasy. Which it does, so your implementation is not called.
Following addition help solve the issue
A.CallTo(() => sutMethod.Execute()).CallsBaseMethod();
This calls the virtual method Executeof FooBar

Spring data jpa. Partial custom repository implemantation

We can write custom implementation of repository:
interface UserRepositoryCustom {
public void someCustomMethod(User user);
}
class UserRepositoryImpl implements UserRepositoryCustom {
public void someCustomMethod(User user) {
// Your custom implementation
}
}
But what if I want customize only some methods? For example:
interface UserRepositoryCustom {
public User findByFirstName(String firstName);
#Query("select u.firstName from User u where u.age > 18")
public Set<String> findAllAdultUsers();
public void someCustomMethod(User user);
}
class UserRepositoryImpl implements UserRepositoryCustom {
//I want implement only this method
public void someCustomMethod(User user) {
// Your custom implementation
}
}
If I declare a class, which implements an interface, I have to implement all methods, but I want to write custom logic for only one method.
Is it possible to do this? Maybe I can make this class abstract? Will spring data resolve this?
I think only solution is to split methods in 2 interfaces: first - for spring query method, and second - for custom implementation, as shows in doc: http://docs.spring.io/spring-data/data-jpa/docs/current/reference/html/#repositories.single-repository-behaviour.
But I think solution with abstract class would be more natural and logic: you provide only needed method implementations and spring data do the rest for you.
Let's say you have a repository with a few methods whose implementations are generated by Spring:
interface UserRepository extends CrudRepository<User,String> {
List<User> findUserByLastname(String lastName);
}
In order to add a method with a custom implementation, you need to create another interface that only contains the methods you want to customize, and make your repository extend the custom one:
interface CustomUserRepository {
User someCustomMethod();
}
interface UserRepository extends CrudRepository<User,String>, CustomUserRepository {
List<User> findUserByLastname(String lastName);
}
You can then implement the extra methods by creating an implementation class for the new interface:
class CustomUserRepositoryImpl implements CustomUserRespository {
#Override
User someCustomMethod() {
// implementation goes here.
}
}
The class name is important here: in order for Spring to find it, it should be the name of the interface that is being extended with Impl on the end.
The implementation repository is a normal Spring bean, so you can autowire a constructor to inject various dependencies.
There is a much more detailed tutorial here: https://www.baeldung.com/spring-data-composable-repositories.

#Inject a Morphia DAO with CDI?

I'm writing a Java EE 6 application that makes use of Morphia to persist objects to MongoDB. I'd like to be able to #Inject my DAO classes where necessary, so I created a Factory class that instantiates the DAO appropriately. It looks something like this:
public class MyDAOFactory {
#Inject
private Datastore mongoDatastore = null;
/**
* Creates the DAO
*/
#Produces
#ApplicationScoped
public MyDAO createDAO() {
MyDAO dao = new MyDAO(
this.mongoDatastore);
return dao;
}
}
The code compiles fine, but when I run my application on JBoss EAP 6.1 it complains because MyDAO does not have a no-arg constructor. I would add one, but the Morphia BasicDAO class does not have one either, so I don't know that it would work that way.
Is there a way to #Inject a DAO instance into my EJB, Servlet, etc.? Or do I need to manually instantiate it every time?
It seems that CDI needs the no-arg constructor for MyDAO for some reason. Maybe because of how you use this bean (see specs ch.5.4 "Client Proxies" for possible reasons).
You cannot create a default constructor, because the base class does not have one and, from what I see from the code the super constructors make immediate use of their args. Therefore passing null to super() from a no-arg constructor will throw errors.
My suggestion is to create an interface (optionally extending org.mongodb.morphia.dao.DAO), e.g. MyDAOInterface that has all public business methods of MyDAO. Then modify MyDAO to implement this interface and change your producer to return MyDAOInterface:
public interface MyDAOInterface extends DAO {...}
public class MyDAO implements MyDAOInterface {
// same implementation
}
public class MyDAOFactory {
#Inject
private Datastore mongoDatastore = null;
/**
* Creates the DAO
*/
#Produces
#ApplicationScoped
public MyDAOInterface createDAO() {
MyDAO dao = new MyDAO(this.mongoDatastore);
return dao;
}
}
By the way, programming to interfaces has the extra benefit of making your code more testable, so it is worth the minor hassle.

GWT: transmit an interface with an IsSerializable Object

Good morning everybody,
I'm trying to transmit the following calls with an GWT RPC call:
public class MVCController extends Composite implements IsSerializable {
//..
private MVCClass listeners;
public void addListener(MVCClass _listener){
listeners = _listener;
}
//....
}
The MVCClass is the following interface:
import com.google.gwt.user.client.rpc.IsSerializable;
public interface MVCInterface extends IsSerializable{
public abstract void labelTextChange(String _text);
}
Whenever I make the RPC call, the application crashes, saying something about
Failed to create an instance of ... via deferred binding
Can I send an Interface with an RFC call?
Regards Stefan
You can not serialize a gwt widget that is why you get that exception. Your class MVCController extends from Composite whose base class is Widget..