It’s an identification number that will uniquely identify something. The idea being that id number will be universally unique. Thus, no two things should have the same uuid. In fact, if you were to generate 10 trillion uuids, there would be something along the lines of a .00000006 chance of two uuids being the same.
Annotations are primarily used by code that is inspecting other code. They are often used for modifying (i.e. decorating or wrapping) existing classes at run-time to change their behavior. Frameworks such as JUnit and Hibernate use annotations to minimize the amount of code you need to write yourself to use the frameworks. Oracle has a … Read more
Declarative programming is when you write your code in such a way that it describes what you want to do, and not how you want to do it. It is left up to the compiler to figure out the how. Examples of declarative programming languages are SQL and Prolog.
One key feature in a functional language is the concept of first-class functions. The idea is that you can pass functions as parameters to other functions and return them as values. Functional programming involves writing code that does not change state. The primary reason for doing so is so that successive calls to a function … Read more
The following answer is from Gof book (Design Patterns) An object’s class defines how the object is implemented. The class defines object’s internal state and the implementation of its operations. In contrast, an object’s type only refers to its interface – a set of requests to which it can respond. An object can have many … Read more
You might want to take a look at what Martin Fowler has to say about MVC, MVP and UI architectures in general at Martin Fowlers site.
A functional language (ideally) allows you to write a mathematical function, i.e. a function that takes n arguments and returns a value. If the program is executed, this function is logically evaluated as needed.1 A procedural language, on the other hand, performs a series of sequential steps. (There’s a way of transforming sequential logic into … Read more
A literal is “any notation for representing a value within source code” (wikipedia) (Contrast this with identifiers, which refer to a value in memory.) Examples: “hey” (a string) false (a boolean) 3.14 (a real number) [1,2,3] (a list of numbers) (x) => x*x (a function) /^1?$|^(11+?)\1+$/ (a regexp) Some things that are not literals: std::cout … Read more
The books Agile Software Development, Principles, Patterns, and Practices and Agile Principles, Patterns, and Practices in C# are the best resources for fully understanding the original goals and motivations behind the Dependency Inversion Principle. The article “The Dependency Inversion Principle” is also a good resource, but due to the fact that it is a condensed … Read more
Boxed values are data structures that are minimal wrappers around primitive types*. Boxed values are typically stored as pointers to objects on the heap. Thus, boxed values use more memory and take at minimum two memory lookups to access: once to get the pointer, and another to follow that pointer to the primitive. Obviously this … Read more