subtype

问题 I'm trying to deserialize this json: { "teaser": [{ "id": "...", "type": "category", "url": "https:...", },{ "id": "...", "type": "brand", "url": "https:...", "videoCount": 1, },{ "id": "...", "type": "video", "url": "https:...", "headline": "...", }] } It has a list of teasers whereby each teaser is different depending on its type. These would be my objects: public class StartPage { public IList<Teaser> Teaser { get; set; } } public abstract class Teaser { public string Id { get; set; }

问题 I have a class called Product and some subclasses extending it. Now in my annotations I have many types, like this: @JsonTypeInfo(use=JsonTypeInfo.Id.NAME, include=JsonTypeInfo.As.WRAPPER_OBJECT) @JsonSubTypes({@Type(value=RoomProduct.class, name="RoomProduct"), @Type(value=GroundProduct.class, name="GroundProduct"), }) And then the definition of my Product class. What I want to do is if Jackson cannot detect that the field is not complying with any of these structures, to return an

问题 I'd like to know about Isabelle/HOL subtypes. I explain a little about why it's important to me in my partial answer to my last SO question: Trying to Treat Type Classes and Sub-types Like Sets and Subsets Basically, I only have one type, so it might be useful to me if I could exploit the power of HOL types through subtypes. I've done searches in the Isabelle documentation, on the Web, and on the Isabelle mailing lists. The word "subtype" is used, though not much, and it seems like it's not a

问题 I am working on a program in which you can register complaints. There are three types of complaints: internal (errors from employees), external (errors from another company) and supplier (errors made by a supplier). They hold different data which cannot be shared. I currently have 4 tables (complaint, employee, company and supplier). Here's a visualisation of the tables: I have a basic understanding of subtypes but I cannot seem to translate them from an ERD into an actual SQL Server database

问题 A friend of mine posed a seemingly innocuous Scala language question last week that I didn't have a good answer to: whether there's an easy way to declare a collection of things belonging to some common typeclass. Of course there's no first-class notion of "typeclass" in Scala, so we have to think of this in terms of traits and context bounds (i.e. implicits). Concretely, given some trait T[_] representing a typeclass, and types A , B and C , with corresponding implicits in scope T[A] , T[B]

问题 Anyone see this before? I have a large Visual Studio project that keeps adding [Subtype]Designer[/Subtype] to my .vcproj then removing it on the next open and close of the project. There is only one class defined in StoredImageControl.cs . Anyone know how to shut this off as it is really messing up my revision control. This is before: <EmbeddedResource Include="StoredImageControl.resx"> <DependentUpon>StoredImageControl.cs</DependentUpon> </EmbeddedResource> This is after <EmbeddedResource

问题 Is it bad to implement supertype and subtype to the entire data in a database? I need some advice on this before moving to this direction... For instance, I have these tables as objects and they are related, users pages images entities table as the supertype entity_id entity_type 1 page 2 page 3 user 4 user 5 image 6 image users table user_id entity_id 1 3 2 4 pages table page_id entity_id 1 1 2 2 images table image_id entity_id 1 5 2 6 here is the table to map images table with entities

问题 let's say I wanted to have something like the following: abstract class PDF[T, S <: PDF[T, _]] { def fit(obs: Seq[T], weights: Seq[Double]): S } class PDFGaussian(val mu: Double, val Sigma: Double) extends PDF[Double, PDFGaussian] { def fit(obs: Seq[Double], weights: Seq[Double]): PDFGaussian = new PDFGaussian(...) // bla bla bla } So, basically, what I want is to have the fit function to return an instance of the type of its enclosing class which obviously must be a subclass of PDF[T] .

问题 I hear a lot about subtyping tables when designing a database, and I'm fully aware of the theory behind them. However, I have never actually seen table subtyping in action. How can you create subtypes of tables? I am using MS Access, and I'm looking for a way of doing it in SQL as well as through the GUI (Access 2003). Cheers! 回答1: An easy example would be to have a Person table with a primary key and some columns in that table. Now you can create another table called Student that has a

问题 In Scala, the PartialFunction[A, B] class is derived from type Function[A, B] (see Scala Reference, 12.3.3). However, this seems counterintuitive to me, since a Function (which needs to be defined for all A ) has more stringent requirements than a PartialFunction , which can be undefined at some places. The problem I've came accross was that when I have a partial function, I cannot use a Function to extend the partial function. Eg. I cannot do: (pf orElse (_)=>"default")(x) (Hope the syntax