With design patterns, there usually is no “more advantageous” solution that works for all cases. It depends on what you need to implement. From Wikipedia: Builder focuses on constructing a complex object step by step. Abstract Factory emphasizes a family of product objects (either simple or complex). Builder returns the product as a final step, … Read more
Use an enum: public enum Foo { INSTANCE; } Joshua Bloch explained this approach in his Effective Java Reloaded talk at Google I/O 2008: link to video. Also see slides 30-32 of his presentation (effective_java_reloaded.pdf): The Right Way to Implement a Serializable Singleton public enum Elvis { INSTANCE; private final String[] favoriteSongs = { “Hound … Read more
In 2008 I provided a C++98 implementation of the Singleton design pattern that is lazy-evaluated, guaranteed-destruction, not-technically-thread-safe: Can any one provide me a sample of Singleton in c++? Here is an updated C++11 implementation of the Singleton design pattern that is lazy-evaluated, correctly-destroyed, and thread-safe. class S { public: static S& getInstance() { static S … Read more
The blog post you quoted overstates its claim a bit. FP doesn’t eliminate the need for design patterns. The term “design patterns” just isn’t widely used to describe the same thing in FP languages. But they exist. Functional languages have plenty of best practice rules of the form “when you encounter problem X, use code … Read more
I asked a similar question, but where possible I try to copy the names already in the .NET framework, and I look for ideas in the Java and Android frameworks. It seems Helper, Manager, and Util are the unavoidable nouns you attach for coordinating classes that contain no state and are generally procedural and static. … Read more
MVC/MVVM is not an either/or choice. The two patterns crop up, in different ways, in both ASP.Net and Silverlight/WPF development. For ASP.Net, MVVM is used to two-way bind data within views. This is usually a client-side implementation (e.g. using Knockout.js). MVC on the other hand is a way of separating concerns on the server-side. For … Read more
What makes you say that either a singleton or a static method isn’t thread-safe? Usually both should be implemented to be thread-safe. The big difference between a singleton and a bunch of static methods is that singletons can implement interfaces (or derive from useful base classes, although that’s less common, in my experience), so you … Read more
Paraphrased from Brian Button: They are generally used as a global instance, why is that so bad? Because you hide the dependencies of your application in your code, instead of exposing them through the interfaces. Making something global to avoid passing it around is a code smell. They violate the single responsibility principle: by virtue … Read more
The Inversion-of-Control (IoC) pattern, is about providing any kind of callback (which controls reaction), instead of acting ourself directly (in other words, inversion and/or redirecting control to external handler/controller). The Dependency-Injection (DI) pattern is a more specific version of IoC pattern, and is all about removing dependencies from your code. Every DI implementation can be … Read more
Model-View-Presenter In MVP, the Presenter contains the UI business logic for the View. All invocations from the View delegate directly to the Presenter. The Presenter is also decoupled directly from the View and talks to it through an interface. This is to allow mocking of the View in a unit test. One common attribute of … Read more