encapsulation

问题 I have a ManagerClass that manages classes that derive from an abstract BaseClass. I need it so that only the ManageClass can access certain methods on the BaseClass. I also need certain methods to be accessible outside the scope of the ManagerClass. Since C# doesn't have friends, I'm encapsulating the BaseClass inside the ManagerClass. The problem: BaseClass is not accessible to derive from Making BaseClass public,means allowing DoStuff() and DoOtherStuff() to be called from outside the

问题 When I create a GameObject like below I want my component to have/set mandatory fields. GameObject go = new GameObject("MyGameObject"); MyComponent myComponent = go.addComponent(MyComponent); Since I cannot use a constructor to set private fields I either need a setter for these fields or a public Init function that sets multiple mandatory properties. But this allows changing the values anywhere in the code and unlike a constructor with overloads it's not obvious that Init "needs to" or "can

问题 PHP has magic methods like __get() and __set() . Is there any alternative for it in vb.net. Or is there any other tricks that can be done instead? This was what i done in php private $data = array(); public function __construct($arData) { $data['var1'] = 'value1'; $data['var2'] = 'value2'; $data['var3'] = 'value3'; } public function __get($propertyName) { if(!array_key_exists($propertyName, $this->data)) throw new Exception("Invalid property"); else return $this->data[$propertyName]; } Now i

问题 I realy don't understand why it works, but below code shows an example of calling private method from the world without any friend classes: class A { public: virtual void someMethod(){ std::cout << "A::someMethod"; } }; class B : public A { private: virtual void someMethod(){ std::cout << "B::someMethod"; } }; int main(){ A* a = new B; a->someMethod(); } outputs: B::someMethod Doesn't it violates encapsulation rules in C++? For me this is insane. The inheritance is public, but the access

问题 I have created 2 timers in 2 separate classes. One timer increments int counter. and the other uses a get method and prints out the value of int counter. The problem is the second timer only prints out 0, 0, 0 etc if i use private int counter whereas if i were to use private static counter it prints out 1,2,3,4,5 etc which is what i want. But i would rather not use static because ive been told its bad practice. Here is my main class: import java.util.Timer; public class Gettest { public

问题 Is it possible to get security.context inside an entity class? I know the following doesn't work. I don't know how to implement the $user part. /** * Set createdAt * * @ORM\PrePersist */ public function setCreatedAt() { $user = $this->get('security.context')->getToken()->getUser(); $this->owner = $user->getId(); $this->createdAt = new \DateTime(); $this->updatedAt = new \DateTime(); } 回答1: For datetimes: For the timestamps you are probably best of using the @hasLifeCycleCallback annotation

问题 Traits in Scala can be used as both mixins and interfaces. It leads to some inconsistence - if I want to close some method inside trait, I just can't do that: object Library { protected trait A { def a: Int = 5 } trait B extends A { private override def a: Int = super.a } //I want to close `a` memeber for all traits extending B; it's still possible to open it in some another trait `C extends A`, or even `Z extends B with C` } // Exiting paste mode, now interpreting. <console>:10: error:

问题 I recently read a StackOverflow question that indicated, when accessing variables, it is faster to use the stack than the heap: void f() { int x = 123; // <- located in stack } int x; // <- located in heap void f() { x = 123 } However, I can't work it through my head which is faster in my example (since I assume they are both using the stack). I'm working on hitbox calculation and such, which uses alot of X-Y, width, height variables (up to 10-20 times for each) in the function. Is it faster

问题 how to separate the serialize method from this code and encapsulate it to a another class so that we don't have to write it in every class we create. class Test { private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & BOOST_SERIALIZATION_NVP(a); ar & BOOST_SERIALIZATION_NVP(b); ar & BOOST_SERIALIZATION_NVP(emp); } int a; int b; Employee *emp; public: Test(int a, int b,int c, int d) { this->a = a; this->b = b;

问题 I have a two-part question. First, I understand that C++ provides only class-level data encapsulation, meaning that all objects of the same class have access to one another's private members. I understand the reason for this, but have found some links (i.e. http://www.programmerinterview.com/index.php/c-cplusplus/whats-the-difference-between-a-class-variable-and-an-instance-variable/) which appear to contradict this point, suggesting that I could do the following: class testclass { private: /