There are some equivalents of constructors for when the zero values can’t make sensible default values or for when some parameter is necessary for the struct initialization. Supposing you have a struct like this : type Thing struct { Name string Num int } then, if the zero values aren’t fitting, you would typically construct … Read more
COMPOSITION Imagine a software firm that is composed of different Business Units (or departments) like Storage BU, Networking BU. Automobile BU. The life time of these Business Units is governed by the lifetime of the organization. In other words, these Business Units cannot exist independently without the firm. This is COMPOSITION. (ie the firm is … Read more
A switch is like any other control structure. There are places where it’s the best/cleanest solution, and many more places where it’s completely inappropriate. It’s just abused way more than other control structures. In OO design, it’s generally considered preferable in a situation like yours to use different message types/classes that inherit from a common … Read more
Head First Design Patterns and the Design Pattern Wikipedia page are the best resources for beginners. FluffyCat is another good, free online resource for design patterns in both Java and PHP. The Gang of Four book is where to go afterward, but it’s fairly advanced, so I’d wait until you have a pretty firm grasp … Read more
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
Should you ever use protected member variables? Depends on how picky you are about hiding state. If you don’t want any leaking of internal state, then declaring all your member variables private is the way to go. If you don’t really care that subclasses can access internal state, then protected is good enough. If a … Read more
What I believe is this: Cohesion refers to the degree to which the elements of a module/class belong together, it is suggested that the related code should be close to each other, so we should strive for high cohesion and bind all related code together as close as possible. It has to do with the … Read more
While of course this isn’t the idiomatic way to create objects and methods in julia, there’s nothing horribly wrong with it either. In any language with closures you can define your own “object systems” like this, for example see the many object systems that have been developed within Scheme. In julia v0.5 there is an … Read more
Property Set is for objects (e.g., class instances) Property Let is for “normal” datatypes (e.g., string, boolean, long, etc.)
What is Immutability? Immutability is applied primarily to objects (strings, arrays, a custom Animal class) Typically, if there is an immutable version of a class, a mutable version is also available. For instance, Objective-C and Cocoa define both an NSString class (immutable) and an NSMutableString class. If an object is immutable, it can’t be changed … Read more