I normally follow one easy principle: Everything that is mandatory for the correct existence and behavior of the class instance should be passed and done into the constructor. Every other activity is done by other methods. The constructor should never: use other methods of the class with the purpose of using overriding behavior act on … Read more
When I was working on my doctorate, the faculty gave us this rule for seminars – and it has proved very useful since: Tell ’em what you’re gonna tell ’em. (E.g., brief introductory problem description and results abstract) Tell ’em. (E.g. technical details comprising the bulk of the time) Tell ’em what you told ’em. … Read more
Strategy allows for a reusable algorithm to be used in more than one place. If you have an algorithm that can be provided by your consumer and can be used in several places, this is a good spot for Strategy (sorting algorithms, predicates, comparers… are good examples of that). Template method is specifically targeted at … Read more
The core idea behind building a fluent interface is one of readability – someone reading the code should be able to understand what is being achieved without having to dig into the implementation to clarify details. In modern OO languages such as C#, VB.NET and Java, method chaining is one way that this is achieved, … Read more
Step away from the computer and grab some paper and a pen or pencil if you prefer. If I’m around the computer then I try to program a solution right then and there and it normally doesn’t work right or it’s just crap. Pen and paper force me to think a little more.
I’ve found this to be a language and programming-paradigm thing. One paradigm — OOP — refers to objects with member methods, which conceptually are how you send messages to those objects (this view is reflected in UML, for example). Another paradigm — functional — may or may not involve classes of objects, but functions are … Read more
They are pretty similar but each has a few special features. switch switch is usually more compact than lots of nested if else and therefore, more readable If you omit the break between two switch cases, you can fall through to the next case in many C-like languages. With if else you’d need a goto … Read more
An executable file is one which can be executed; you would run it on the commandline by writing the name of the file itself as the command. On Unix systems, the file’s “executable” flag must also be set. On Windows, the file’s extension must be one of a fixed set of executable file extensions, including … Read more
Abstract Data Type(ADT) is a data type, where only behavior is defined but not implementation. Opposite of ADT is Concrete Data Type (CDT), where it contains an implementation of ADT. Examples: Array, List, Map, Queue, Set, Stack, Table, Tree, and Vector are ADTs. Each of these ADTs has many implementations i.e. CDT. The container is … Read more
A magic number is a direct usage of a number in the code. For example, if you have (in Java): public class Foo { public void setPassword(String password) { // don’t do this if (password.length() > 7) { throw new InvalidArgumentException(“password”); } } } This should be refactored to: public class Foo { public static … Read more