interface

问题 My question is, if an interface that is implemented implicitly by extending a class that already implements it, should be explicitly implemented by the class, if the class wants to advertise the fact, that it fulfills the contract of that interface. For instance, if you want to write a class, that fulfills the contract of the interface java.util.List . You implement this, extending the class java.util.AbstractList , that already implements the interface List . Do you explicitly declare, that

问题 I am relatively new to "design patterns" as they are referred to in a formal sense. I've not been a professional for very long, so I'm pretty new to this. We've got a pure virtual interface base class. This interface class is obviously to provide the definition of what functionality its derived children are supposed to do. The current use and situation in the software dictates what type of derived child we want to use, so I recommended creating a wrapper that will communicate which type of

问题 I am trying to link R, version 3.2.0, with CPLEX. I have used the following commands to install "cplexAPI" package: 1- install.Rtools() 2- install.packages("cplexAPI") I have installed Rtools successfully but I am getting an error saying "ilcplex/cplex.h: No such file or directory" in "cplexAPI" installation. Could you please help me out here? 回答1: You can install cplexAPI manually: R CMD INSTALL --configure-args=" \ --with-cplex-include=/path/to/cplex_include/dir \ --with-cplex-lib=/path/to

问题 I have a list of objects I need to sort according to properties of one of their fields. I've heard that SortedMap and Comparators are the best way to do this. Do I implement Comparable with the class I'm sorting, or do I create a new class? How do I instantiate the SortedMap and pass in the Comparator? How does the sorting work? Will it automatically sort everything as new objects are inserted? EDIT: This code is giving me an error: private TreeMap<Ktr> collection = new TreeMap<Ktr>(); (Ktr

问题 I have a list of objects I need to sort according to properties of one of their fields. I've heard that SortedMap and Comparators are the best way to do this. Do I implement Comparable with the class I'm sorting, or do I create a new class? How do I instantiate the SortedMap and pass in the Comparator? How does the sorting work? Will it automatically sort everything as new objects are inserted? EDIT: This code is giving me an error: private TreeMap<Ktr> collection = new TreeMap<Ktr>(); (Ktr

问题 I recently reworked one of my own libraries to try out separating interface from implementation. I am having on final issue with a class that is meant to return an instance of another class. In the interface definition, I do something like struct IFoo { virtual const IBar& getBar() = 0; } and then in the concrete Foo getBar looks like const IBar& Foo::getBar() { Bar ret = Bar(); return ret; } The problem is ret gets deleted as soon as getBar is done, causing a big crash when the copy

问题 I recently reworked one of my own libraries to try out separating interface from implementation. I am having on final issue with a class that is meant to return an instance of another class. In the interface definition, I do something like struct IFoo { virtual const IBar& getBar() = 0; } and then in the concrete Foo getBar looks like const IBar& Foo::getBar() { Bar ret = Bar(); return ret; } The problem is ret gets deleted as soon as getBar is done, causing a big crash when the copy

问题 In Android App Integrated Facebook Api. I am using Facebook sdk:4.21.0,But when GraphRequest Call birthday not return in Json Response. Please let me know whats wrong. I am also tested through give the public permission to date of birth of user. GraphRequest request = GraphRequest.newMeRequest( AccessToken.getCurrentAccessToken(), new GraphRequest.GraphJSONObjectCallback() { @Override public void onCompleted(JSONObject object, GraphResponse response) { LogUtils.logE(TAG, "JsonResponse: " +

问题 I'm trying to make my client subscribe to events that happen on my server. I have an interface that looks like this: public delegate void RemoteEventHandler(object sender, ClientEventArgs args); [Serializable] public class ClientEventArgs : EventArgs { public ClientEventArgs() { } public ClientEventArgs(Client _client) { MyClient = _client; } public Client MyClient { get; set; } } public interface IMonitor { event RemoteEventHandler RemoteEvent; } My Server Class looks like this: public class

问题 So I did tons and tons of work trying to make an interface for a common set of classes. The idea was to make an interface that each class could use within the set, but ultimately each class is different. Turns out interfaces do not like shared members. What I tried: Public Interface ISomeInterface Shared Property Meta() as Object End Interface Public Class A Implements ISomeInterface Shared Public Property Meta() as Object Implements ISomeInterFace.Meta 'Set/get methods End Propery Public