object-composition

问题 Composition is a useful alternative to inheritance when one wants to cascade method calls from child to parent, see child extended class method calls its super version but that still only sees child data However, for the child to present an interface that is compatible with parent type, one must implement a potentially large number of stub methods that all have the same form, namely they just relay the call to the former parent (which is now a component). My question here, is it possible to

问题 In python, I want to mimic the following behavior with delegation by composition: class Object1(object): def __init__(self): pass def method1(self): print "This is method 1 from object 1" return self.method2() def method2(self): raise Exception class Object2(Object1): def method2(self): print "This is method 2 from object 2" obj2 = Object2() obj2.method1() The output is: This is method 1 from object 1 This is method 2 from object 2 In other words, I want to be able to create a class that

问题 Since I'm a newbie in C++, here it goes! I have a base class (I'm not using inheritance anywhere) with two objects from two other classes. I need to have access from a private member to the other in another class. class base { private: myClass1 m1; myClass2 m2; public: base() {}; ~base() {}; }; class myClass1 { private: int m_member1; public: myClass1() {}; ~myClass1() {}; }; class myClass2 { private: int m_member2; public: myClass2() {}; ~myClass2() {}; int sum_members_because_yes(void) {

问题 I'm trying to adopt composition over inheritance when I create Swing components (which means I created a class that does not extend anything, specially not a Swing component such as JPanel ) but I'm stumpling upon an issue with the Window Builder plugin for Eclipse when I try to switch to the design view of my code. It throws the following exception: No root methods The parser can't find any root method(s) (entry points for parsing). The parser starts parsing from known method(s) for each GUI