They are called Traits and are available since PHP 5.4. They are imported into another class or namespace using use keyword which is included since PHP 5.0 like importing a regular class into another class. They are single inheritance. The primary reason for the implementation of traits is because of the limitation of single inheritance. … Read more
Java does not support multiple inheritance. There are a few workarounds I can think of: The first is aggregation: make a class that takes those two activities as fields. The second is to use interfaces. The third is to rethink your design: does it make sense for a Preferences class to be both a PreferenceActivity … Read more
A Java class can only extend one parent class. Multiple inheritance (extends) is not allowed. Interfaces are not classes, however, and a class can implement more than one interface. The parent interfaces are declared in a comma-separated list, after the implements keyword. In conclusion, yes, it is possible to do: public class A implements C,D … Read more
Instead of using the recipe as mentioned by jdi, you can directly use: class M_C(M_A, M_B): pass class C(A, B): __metaclass__ = M_C
Q1. As interfaces are having only abstract methods (no code) so how can we say that if we are implementing any interface then it is inheritance ? We are not using its code. We can’t. Interfaces aren’t used to achieve multiple inheritance. They replace it with safer, although slightly less powerful construct. Note the keyword … Read more
The answer to the duplicate operation is: To solve multiple inheritance issue a class implementing two interfaces providing a default implementation for the same method name and signature must provide an implementation of the method. [Full Article] My answer to your question is: Yes, it is a form of multiple inheritance, because you can inherit … Read more
Objective-C doesn’t support multiple inheritance, and you don’t need it. Use composition: @interface ClassA : NSObject { } -(void)methodA; @end @interface ClassB : NSObject { } -(void)methodB; @end @interface MyClass : NSObject { ClassA *a; ClassB *b; } -(id)initWithA:(ClassA *)anA b:(ClassB *)aB; -(void)methodA; -(void)methodB; @end Now you just need to invoke the method on the … Read more
No, there is no way to implement the same method in two different ways in one class in Java. That can lead to many confusing situations, which is why Java has disallowed it. interface ISomething { void doSomething(); } interface ISomething2 { void doSomething(); } class Impl implements ISomething, ISomething2 { void doSomething() {} // … Read more
Well, when dealing with multiple inheritance in general, your base classes (unfortunately) should be designed for multiple inheritance. Classes B and C in your example aren’t, and thus you couldn’t find a proper way to apply super in D. One of the common ways of designing your base classes for multiple inheritance, is for the … Read more
Anonymous classes must extend or implement something, like any other Java class, even if it’s just java.lang.Object. For example: Runnable r = new Runnable() { public void run() { … } }; Here, r is an object of an anonymous class which implements Runnable. An anonymous class can extend another class using the same syntax: … Read more