inheritance

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()

问题 I am creating a Class Library which contains all the custom classes I regularly use in the applications I develop. This library is compiled and added as a Reference in each of my applications, enabling me to call on the custom classes contained within the library. The custom classes in my library include multiple layers of inheritance, but all ultimately have their origins in a base class I call 'Alpha'. In that class I also hold my connection string so that it is inherited by all other

问题 OK, that title is a little unclear, but I can't think of a better way of putting it, other than explaining it... Say I have a class Animal , with a static, generic method: public static T Create<T>() where T : Animal { // stuff to create, initialize and return an animal of type T } And I have subclasses Dog , Cat , Hamster etc. In order to get a Dog , I can write: Dog d = Animal.Create<Dog>(); or Dog d = Dog.Create<Dog>(); which is really the same thing. But it seems kinda silly to have to

问题 OK, that title is a little unclear, but I can't think of a better way of putting it, other than explaining it... Say I have a class Animal , with a static, generic method: public static T Create<T>() where T : Animal { // stuff to create, initialize and return an animal of type T } And I have subclasses Dog , Cat , Hamster etc. In order to get a Dog , I can write: Dog d = Animal.Create<Dog>(); or Dog d = Dog.Create<Dog>(); which is really the same thing. But it seems kinda silly to have to

问题 I'm having problem implementing a Kotlin class which uses Java-defined generics/interfaces classes from MockMvc library. Library classes: public interface ConfigurableMockMvcBuilder<B extends ConfigurableMockMvcBuilder<B>> extends MockMvcBuilder { // ... <T extends B> T defaultRequest(RequestBuilder requestBuilder); // ... } @FunctionalInterface public interface MockMvcBuilderCustomizer { /** * Customize the given {@code builder}. * @param builder the builder */ void customize

问题 I'm having problem implementing a Kotlin class which uses Java-defined generics/interfaces classes from MockMvc library. Library classes: public interface ConfigurableMockMvcBuilder<B extends ConfigurableMockMvcBuilder<B>> extends MockMvcBuilder { // ... <T extends B> T defaultRequest(RequestBuilder requestBuilder); // ... } @FunctionalInterface public interface MockMvcBuilderCustomizer { /** * Customize the given {@code builder}. * @param builder the builder */ void customize

问题 The following code: class City { var cityId : String? var cityName : String? } class Town { var townid : String? var townName : String? } class Address : City , Town { var house : String? var street: String? } Generates a compile-time error: Address.swift:38:24: Multiple inheritance from classes 'City' and 'Town' How can I solve his kind of problem? What approach to follow? 回答1: It seems you are overthinking things. Instead of inheritance, try to use more composition. An address should not

问题 What is the difference between a sub-object and a contained object ? For constructing an instance of a class which is derived from another class, first the sub-object has to be created and then the derived object has to be created. Questions: Is it true that derived object contains the sub-object? How can one visualize the difference in the structure of an object a) which contains another object b) which is derived from another class Do the objects in a) and b) have the same structure ? 回答1:

问题 What is the difference between a sub-object and a contained object ? For constructing an instance of a class which is derived from another class, first the sub-object has to be created and then the derived object has to be created. Questions: Is it true that derived object contains the sub-object? How can one visualize the difference in the structure of an object a) which contains another object b) which is derived from another class Do the objects in a) and b) have the same structure ? 回答1:

问题 In a simple inheritance tree, an abstract superclass has two subclasses. The subclasses both store a key-value pair, but but one will be holding a type Encrypted String, and the other one a plain old String. Now, my question is can I do this: @Entity @Inheritance(strategy = InheritanceType.SINGLE_TABLE) public abstract Attribute { @Id private Integer id; @Column(name="attribute_key") private String key; } @Entity public EncryptedAttribute extends Attribute { @Column(name="attribute_value")