Many examples of Adapter are trivial or unrealistic (Rectangle vs. LegacyRectangle, Ratchet vs. Socket, SquarePeg vs RoundPeg, Duck vs. Turkey). Worse, many don’t show multiple Adapters for different Adaptees (someone cited Java’s Arrays.asList as an example of the adapter pattern). Adapting an interface of only one class to work with another seems a weak example … Read more
Encapsulation helps in isolating implementation details from the behavior exposed to clients of a class (other classes/functions that are using this class), and gives you more control over coupling in your code. Consider this example, similar to the one in Robert Martin’s book Clean Code: public class Car { //… public float GetFuelPercentage() { /* … Read more
The main reason to use Fragments are for the backstack and lifecycle features. Otherwise, custom views are more light weight and simpler to implement. At first, I actually tried to build a phone/tablet app using custom views. Everything appeared to work across phones AND tablets, even switching from single panel to split panel. Where I … Read more
I’m very late to answer it. But, I would like to share one example, which I only thought of today. If I told you to cut a piece of paper with dimensions 5m by 5m, then surely you would do that. But suppose I ask you to cut 1000 pieces of paper of the same … Read more
Utility classes aren’t exactly evil, but they can violate the principles that compose a good object-oriented design. In a good object-oriented design, most classes should represent a single thing and all of its attributes and operations. If you are operating on a thing, that method should probably be a member of that thing. However, there … Read more
Cohesion refers to what the class (or module) can do. Low cohesion would mean that the class does a great variety of actions – it is broad, unfocused on what it should do. High cohesion means that the class is focused on what it should be doing, i.e. only methods relating to the intention of … Read more
If you have circular dependency then you doing something wrong. As for example: foo.h —– class foo { public: bar b; }; bar.h —– class bar { public: foo f; }; Is illegal you probably want: foo.h —– class bar; // forward declaration class foo { … bar *b; … }; bar.h —– class foo; … Read more
Interfaces are just contracts or signatures and they don’t know anything about implementations. Coding against interface means, the client code always holds an Interface object which is supplied by a factory. Any instance returned by the factory would be of type Interface which any factory candidate class must have implemented. This way the client program … Read more