spot7.org logo
Home PHP C# C++ Android Java Javascript Python IOS SQL HTML Categories

DI Binding to a subclass


It is possible to archive this with scaldi, but the problem is with the way Environment is defined and used. I assume (at least error tells me this) that Environment is invariant on both of it's type arguments. This is the problem, because you want to treat Environment[User, Authenticator] as a superclass of Environment[User, SessionAuthenticator]. It is not the case if both type arguments are defined as invariant. To fix this issue you can just make the second type argument of Environment covariant with +:

trait Environment[A, +B]

Theoretically it should fix the compile error you shown.


Categories : Scala

Related to : DI Binding to a subclass
how to init a UIButton subclass?
Two things you need there -- (1) cvstPosition need an initial value, either in the declaration or in the init before you call super.init(). (2) That call to fatalError is put in so you don't forget to implement the initializer -- it's basically an on-purpose crash. Delete! Setting initial value in the declaration, no need for an init: class CVSTButton : UIButton { var cvstPosition: Double =

Categories : Swift
Use overridden method from subclass
You need to inject the Sub in the object to achieve that. If you let it to be in the class A constructor, it only has visibility to A.Sub. Then, make a constructor for A that accepts an A.Sub and subclasses: public A(Sub sub) { this.sub = sub; }

Categories : Java
Swift subclass UIView
I usually do something like this, its a bit verbose. class MyView: UIView { override init (frame : CGRect) { super.init(frame : frame) addBehavior() } convenience init () { self.init(frame:CGRect.zero) } required init(coder aDecoder: NSCoder) { fatalError("This class does not support NSCoding") } func addBehavior (){ print("Ad

Categories : IOS
Why doesn't my subclass' variable exist?
You need to let the compiler know the class type. As you can see in the error message the compiler currently thinks the class is UILable so you need to update the class type (or cast the class type if you can't).

Categories : IOS
Find invocations of subclass method
Well, due to polymorphism, there's not a good way for the IDE to know that a given Foo isn't potentially a Bar -- so it will show you all calls to doStuff. I suppose it could do more analysis to determine that the concrete type of a Foo really is a Foo -- for example, in the case: final Foo foo = new Foo(); it is definitely not a Bar -- but that's a lot of work for little benefit. You will not

Categories : Java
Recently Add
Reverse list of n elements
scalac: Error: object CharRef in intelliJ 14
Scala - trouble with type inference in lambda expression
Exception on spark test
How can I emulate Haskell's typeclasses in Scala?
Slick: CRUD extension: How to encapsulate implicit mapping:BaseColumnType[T]
Can't find Traverse for sequencing Seq[ValidationNel[String, MyCaseClass]] => ValidationNel[String, Seq[MyCaseClass]]
Tail recursion: internal "loop" function or default values for accumulators
Scala - Add element:MyType to Array = option[MyType] expected
Scala, Composing Function with two values
Using dependent type to generate compile error
How to match all words in a sentence with scala combinators?
Parser Alternative Operator | Fails
ScalaTest assertion mismatch due to Physical Address
Scala implicit parameter and japanese smiley 'foldLeft'
Is it possible to user reduceByKey((x, y, z) => ...)?
How to implement security Authorization using scala and play?
SSO login using scala script
Sum elements based on a predicate
Keep track of completed Futures
API Observable with dynamic caching
java.io.IOException: Remotely closed in gatling
Scala permutations using two lists
Is Scala Either really a Monad
Spark: Use of distinct
Identifying two type wildcards as identical
how to package spark scala application
Pattern Match on Scala `class`
Type mismatch when using higher-kinded types
Scala List match last element
© Copyright 2017 spot7.org Publishing Limited. All rights reserved.