inheritance

问题 I have a HashMap defined: HashMap<String,ArrayList<Thing>> hashmap = new HashMap<>(); I do need an ArrayList since I want one key to have multiple values. This was the best solution I found for that problem. The Thing class is a parent class for a bunch of other classes. Problem is when I try to add I get an error. hashmap.put(b, world.ports); This is the error: no suitable method found for put(String,ArrayList<SeaPort>) method Map.put(String,ArrayList<Thing>) is not applicable (argument

问题 I have a HashMap defined: HashMap<String,ArrayList<Thing>> hashmap = new HashMap<>(); I do need an ArrayList since I want one key to have multiple values. This was the best solution I found for that problem. The Thing class is a parent class for a bunch of other classes. Problem is when I try to add I get an error. hashmap.put(b, world.ports); This is the error: no suitable method found for put(String,ArrayList<SeaPort>) method Map.put(String,ArrayList<Thing>) is not applicable (argument

问题 I'm trying to do something that seems like it should be fairly common but I've been unable to find anyone discussing it. this post on stackoverflow is similar to what I'm trying to do, but not quite the same. I have an abstract base class: #ifndef _ABASECLASS_H_ #define _ABASECLASS_H_ using namespace std; #include <iostream> #define CALL_MBR_FUNC(object, ptr_to_mem_func) ((object).*(ptr_to_mem_func)) class aBaseClass { public: typedef void (aBaseClass::*aBaseClass_mem_func)(); int A; int B;

问题 I'm trying to do something that seems like it should be fairly common but I've been unable to find anyone discussing it. this post on stackoverflow is similar to what I'm trying to do, but not quite the same. I have an abstract base class: #ifndef _ABASECLASS_H_ #define _ABASECLASS_H_ using namespace std; #include <iostream> #define CALL_MBR_FUNC(object, ptr_to_mem_func) ((object).*(ptr_to_mem_func)) class aBaseClass { public: typedef void (aBaseClass::*aBaseClass_mem_func)(); int A; int B;

问题 I'm implementing a model: It has structs ClientSummary and ClientDetails ClientDetails struct has all properties of ClientSummary struct + some extra properties Both structs have main initializer init(jsonDictionary: [String: Any]) inits of ClientSummary and ClientDetails share big part of the code There is an extension which will work with shared functionality of those structs. The most straightforward solution which came to my mind is just classic inheritance, but it doesn't work for value

问题 This question already has answers here : Java and inherited static members [duplicate] (9 answers) Closed 2 years ago . Let's say I have a base/main abstract class: AbstractObject . AbstractObject is extended by two classes: Object1 and Object2 . Those two templates have many different classes extending from them also, for instance, Object3 , Object4 , and Object5 are inheriting from Object1 , and Object6 , Object7 are inheriting from Object2 . I want each separate class ( Object1 , Object2 ,

问题 I have one base abstract class. @Entity @Table(name = "P_FLD") @Inheritance(strategy = InheritanceType.JOINED) @DiscriminatorColumn(name = "FLD_DISCRIMINATOR", columnDefinition = "CHAR(3)") abstract public class AbstractPassbookField and some classes that extends it. For example: @Entity @DiscriminatorValue("F") @Table(name = "P_FLD_F") public class PassbookFileField extends AbstractPassbookField and i create repository for base entity public interface PassbookRepository extends

问题 I have the following classes in C++: class Event { //... friend ofstream& operator<<(ofstream& ofs, Event& e); }; class SSHDFailureEvent: public Event { //... friend ofstream& operator<<(ofstream& ofs, SSHDFailureEvent& e); }; The code I want to execute is: main() { Event *e = new SSHDFailureEvent(); ofstream ofs("file"); ofs << *e; } This is a simplification, but what I want to do is write into a file several type of Events in a file. However, instead of using the operator << of

问题 I would like to parameterize a type with one of its subclasses. Consider the following: class DataLoader { class Data { /* data specifics to this data loader */ } def getData : Data /* and so on */ } Now I want to make this loader able to asynchronously retrieve data from the network. One of the options is to have it subclass Callable. class DataLoader extends Callable[Data] { class Data { /* ... */ } def call : Data = { ... } } val futureData = executor.submit(new DataLoader) futureData.get

问题 I have some code like this: class Person(object): def drive(self, f, t): raise NotImplementedError class John(Person): def drive(self, f, t): print "John drove from %s to %s" % (f,t) class Kyle(Person): def drive(self, f, t): print "Kyle drove from %s to %s" % (f,t) class RandomPerson(Person): # instansiate either John or Kyle, and inherit it. pass class Vehicle(object): pass class Driver(Person, Vehicle): def __init__(self): # instantiate and inherit a RandomPerson somehow pass d1 = Driver()