encapsulation

I have a class that benefits from the use of constants in its internal implementation, but I would like to limit visibility of these constants. Why doesn't PHP permit private constants? Is there another way to achieve this or is PHP trying to discourage some type of design misstep I am ignorant of? sudhir chauhan Use private static properties. In that case you will have the same variable throughout all objects and if you want to extend its scope to nested, you can expose a getter method to get its value and restrict variables settings. As of PHP 7.1, there are real private constants. private

I try to understand a lot of times but I failed to understand this. Encapsulation is the technique of making the fields in a class private and providing access to the fields via public methods. If a field is declared private, it cannot be accessed by anyone outside the class, thereby hiding the fields within the class. How can we change the values of fields through setter methods? How do we prevent accessing the fields directly? What is the real use of encapsulation? Assume you have an age property. The user can enter a value of -10 , which although is a valid number, is an invalid age. A

Interviewer: What is encapsulation and how do you achieve it in Java? Me: Encapsulation is a mechanism to hide information from the client. The information may be data or implementation or algorithm. We achieve this using access modifiers. Interviewer: This is data hiding. How do we achieve encapsulation in Java? Me : uummmm Concrete Question: Other than 'Access Modifiers', what is the way to implement Encapsulation in Java? More generally encapsulation refers simply to bundling the data (e.g. of an object) with the operations on that data. So you have a class encapsulating data - fields -

If I understand correctly, the typical mechanism for Dependency Injection is to inject either through a class' constructor or through a public property (member) of the class. This exposes the dependency being injected and violates the OOP principle of encapsulation. Am I correct in identifying this tradeoff? How do you deal with this issue? Please also see my answer to my own question below. There is another way of looking at this issue that you might find interesting. When we use IoC/dependency injection, we're not using OOP concepts. Admittedly we're using an OO language as the 'host', but

It is easier to explain on an example so, class base { //.... } class derived1 : public base { //... } In my library, there is a pointer of base class. The user of the library have to make classes derived from either base or derived1 and assign pointer to that class. How can I check what class is user-defined class derived from? Cassio Neri I have some remarks on the proposed compile-time x runtime solutions. In addition to when they are evaluated, is_base_of and dynamic_cast have different requirements and their answers can be different. (1) First of all (as pointed out by others) to use

This question already has an answer here: Why use getters and setters/accessors? [closed] 38 answers We always say that data will be encapsulated if we simply define variables private and define getters setters to access those variables. My question is if we can access the variables (data) though via getters and setters, how come data is hidden or safe? I googled a lot for an explanation, but I found nothing. Every one just said in their blogs and posts that it is a data hiding technique, but it has not been explained/elaborated. mithilatw The way I understand your question is, although we