So I'm trying to get my head around this for a while now, but I don't seem to succeed. In my application I'm using a generic repository with Entity Framework Core.
Hence my Repository always expect that it's accessed from a class who's BaseEntity or has inherited from that certain class.
Now I want to implement .Net Core Identity with it. But My User class is inheriting from BaseEntity. But I'd also need it to inherit from Identity in order to make it work I guess. How am I able to still use Identity?
C# only supports single inheritance. You cannot inherit from two different classes. Additionally your Identity user class, must inherit from IdentityUser. You have no choice in that. As a result, the best you can do is make your user class and the rest of your entity classes implement the same interface, i.e. IEntity. Then, instead of constraining your generic type as BaseEntity, use IEntity instead.
Of course, this means you will incur a bit of code duplication as you'll have to implement IEntity separately on both BaseEntity and your user class. However, that is unavoidable.
Related
I always got problems with the private variable declaration.
For example FlatFileItemWrite. I would like to extend these class and overwrite the 'doRead' method. This would not work because some of the used variables are declared private. This leads to copying the complete code in an own class for overwriting one method.
Sometime even this does not work because the class extends an other class which has variables declared visible only for the same package. Then you need to copy this class also.
Then I will miss updates in the original classes with new versions. So would it not be better to use protected instead?
I can imaging only a very few reasons to use private instead of protected. For my own programs this is not an issue, I could change it on demand. But for a framework it is a pain.
with kind regards
Torsten
If something is declared private within the Spring framework (or any framework for that matter), it's not considered part of the public API. Because of that, you really shouldn't be looking to work with it directly. Doing so really means you're forking the framework and risking not being able to upgrade seamlessly.
As the project lead for Spring Batch, I'd be interested in hearing what you had to do with the FlatFileItemWriter that required you to change things that are marked private.
If the idea behind the framework was to override or extend these methods, they should have been written as being public. (be careful if a framework does not provide these methods or properties as public, since it might depend on them working in a specific way. this would be the primary reason for them being private i can think of. the secondary being that they don't matter outside that class.)
In some cases, you might not need to copy the entire class, but simply inheriting or extending it might be enough.
I'm also looking to extend certain ItemReaders/ItemWriters to support decryption/encryption on i/o. For example, I'd like to extend StaxEventItemReaderStaxEventItemReader in order to read an encrypted stream from the resource, but the FragmentEventReader is private, so I'm unable to wrap its XMLEventReader's InputStream in a decrypter.
I faced the same issue with FlatFileItemWriter.
In the Spring Data I have found very helpful interface called JpaRepository. Because I need more functionality I decided to create my own interface of repository:
public interface BaseRepository<T, ID extends Serializable>
extends JpaRepository<T, ID> {
public <TA, TV> int deleteBy(SingularAttribute<T, TA> attr, TV val);
}
As you can see this is a generic interface. It works fine, but I would like to know how I can test it? Of course I can write integration test for each concrete repository but I am looking for better way.
As usual with testing, you should make sure you know what you're testing. Find answers to these questions:
Do you want to test the underlying database?
Do you want to test the Spring Data repository connector for this respository?
Do you want to test whether your code calls the correct methods on the interface?
Doing #1 is useless: The database vendor has already run thousands of tests on its product. There is rarely a reason to do this effort again.
Doing #2 is useless unless you suspect a bug in the code for Spring Data.
Which leaves us with #3. Use a mocking framework to make sure the method is called at the appropriate places (and maybe check the arguments, too).
That way, you can make sure your code behaves correctly.
If you notice the framework throwing errors or you notice that objects aren't deleted correctly, you can add more tests. But most of the time, this won't happen because of bugs in the database or Spring Data. Instead, your code won't call deleteBy() or it will call the method with the wrong arguments.
So, I am creating a class library that handles user information like username, password, etc. I want to do this so that I can just reference this library with any of my web apps and not have to continuously rewrite the user information part.
In, the user information class library, I want to handle the login. I've done this before in app_code that was a part of the web project by using HttpContext.Current.Session. But, when I try to use it in my class library (even while using System.Web) it throws a compile error saying that HttpContext does not exist in this context. How can I get access to it?
When creating a utility type class that works with a dependency like HttpContext, your best bet is to pass the context or the session into the class either via a constructor or the method call. That way, it is explicit to the consumers of your class that it requires this object to function. This also allows you to test your class in isolation.
Even better, if you are working with a few specific properties that have basic types then you can accept those properties as inputs. That way, you are not creating any dependencies on a UI framework for your utility library.
hi i am having a different projects in my solution in the initial project (default project) i am accessing the global reference to App.xaml.cs in this way :-
App objref = (App)Application.Current;
But now i have added new project to my solution and trying to access the app.xaml.cs in the same way as defined earlier but i am not able to access app.xaml.cs ?
1)can i know the reason
2)What should i do if i want to use it in both the projects ?
Please let me know
Thanks in advance.
You can access it, but the new project will not be familiar with the derived App class that is in your project. To explain further we need to take inheritance into consideration.
There's a generic definition for the Application class that exposes a number of predefined methods. Your App.xaml.cs is a new class definition that is derived from the Application class. It has the methods it inherited plus what ever methods and properties that you've added. To make use of these any code that is seeking to use your extra properties or methods must have access to the class definition. Your classes in the other projects that you've added do not have access to this definition.
You'll need to make a class or interface definition that both projects have access to. There are several ways of organizing this. I'll present one.
Create your main project in the solution. This contains your
App.xaml.cs.
Create your class library project that contains the
other code.
Create a third project called Common that only contains
an Interface definition.
On the Interface definition define all of the methods/properties
that you want both your class library and main project to have
access too.
Have App.Xaml.cs implement this interface.
In the Class Library access var appReference =
(IMyInterfaceName)Applcation.Current. You'll have access to the
methods that were defined in the interface
So we're working on converting some projects at work from Ninject to Autofac, and we've stumbled on something really neat within Ninject that we can't figure out how to do in Autofac. In our application, we have an interface called ISession which is implemented in two different concrete types. One goes to an Oracle database, and the other goes to an MS-SQL database.
We have controllers in our MVC application that need only one concrete implementation of ISession based on which controller they are being injected into. For example:
Bind<IFoo>().To<Foo1>();
Bind<IFoo>().To<Foo2>().WhenInjectedInto<OracleController>();
My question is: how do we achieve the same result in Autofac? When IFoo is injected into any controller, Foo1 should be provided by default, however in one special case, we need Foo2 instead.
Thanks for any help in advance!
With Autofac you can achieve this by doing the registration the other way around. So you should declare that you want to use the "speciel" service when you register the OracleController not when you register the IFoo.
containerBuilder.RegisterType<Foo1>().As<IFoo>();
containerBuilder.RegisterType<Foo2>().Named<IFoo>("oracle");
containerBuilder.RegisterType<OracleController>().WithParameter(ResolvedParameter.ForNamed<IFoo>("oracle"));
The Named registration "oracle" ensures that the default IFoo instance will be Foo1 and you only get Foo2 when you explicitly request it by name.