Design pattern (computer science) There are many types of design patterns, for instance Algorithm strategy patterns addressing concerns related to high-level strategies describing how to exploit application characteristics on a computing platform.Computational design patterns addressing concerns related to key computation identification.Execution patterns that address concerns related to supporting application execution, including strategies in executing streams of tasks and building blocks to support task synchronization.Implementation strategy patterns addressing concerns related to implementing source code to support program organization, andthe common data structures specific to parallel programming.Structural design patterns addressing concerns related to high-level structures of applications being developed. History
Design Patterns Cheat Sheet from DZone Refcardz By Jason McDonald About Design Patterns This Design Patterns refcard provides a quick reference to the original 23 Gang of Four design patterns, as listed in the book Design Patterns: Elements of Reusable Object-Oriented Software. Each pattern includes class diagrams, explanation, usage information, and a real world example. Creational Patterns: Used to construct objects such that they can be decoupled from their implementing system. Singleton pattern There is criticism of the use of the singleton pattern, as some consider it an anti-pattern, judging that it is overused, introduces unnecessary restrictions in situations where a sole instance of a class is not actually required, and introduces global state into an application. In C++ it also serves to isolate from the unpredictability of the order of dynamic initialization, returning control to the programmer. Common uses The Abstract Factory, Builder, and Prototype patterns can use Singletons in their implementation.Facade Objects are often Singletons because only one Facade object is required.State objects are often Singletons.Singletons are often preferred to global variables because: They do not pollute the global namespace (or, in languages with namespaces, their containing namespace) with unnecessary variables.They permit lazy allocation and initialization, whereas global variables in many languages will always consume resources. UML
OpenClassroom Full courses. Short Videos. Free for everyone. Learn the fundamentals of human-computer interaction and design thinking, with an emphasis on mobile web applications. A practical introduction to Unix and command line utilities with a focus on Linux. What have you tried? » Matt Legend Gemmell If you’re a developer and you’re about to ask another developer a technical question (on a forum, via email, on a chat channel, or in person), you’d better be ready to answer the question “What have you tried?” This of course isn’t specific to software developers, but that’s my field and it’s thus the area in which I’m most familiar with the issue which motivated me to write this. I’m (sadly) quite sure that it applies to your own industry too, whatever that might be. The thing is, there’s a disease in the software development world; a sort of sickness. It’s an unusual sickness in that it’s often not something you acquire once you actually join the industry (like greying hair, caffeine addiction and an ulcer), but rather it’s something that new recruits already have when they arrive. Now, a quick clarification before I continue: when I say “new recruits”, I don’t just mean graduates and other young people.
AntiPatterns: The Survival Guide Whereas patterns are good ideas that can be re-applied to new situations, AntiPatterns: The Survival Guide looks at what goes wrong in software development, time and time again. Most software projects fail According to new research, success in 68% of technology projects is "improbable." Poor requirements analysis causes many of these failures, meaning projects are doomed right from the start (ZDnet) Our deadliest hit list begins with the Blob, where one object does most of the work in a project, and proceeds to Continuous Obsolescence, where technology changes so quickly that developers can't keep up. Some of the more entertaining antipatterns include the Poltergeist (where do-nothing classes add unnecessary overhead), the Boat Anchor (a white elephant piece of hardware or software bought at great cost) and the Golden Hammer (a single technology that is used for every conceivable programming problem).
.NET Design Patterns in C# and VB.NET - Gang of Four (GOF) - DoFactory Design patterns are solutions to software design problems you find again and again in real-world application development. Patterns are about reusable designs and interactions of objects. The 23 Gang of Four (GoF) patterns are generally considered the foundation for all other patterns.
Data access object Although this design pattern is equally applicable to most programming languages, most types of software with persistence needs, and most types of databases, it is traditionally associated with Java EE applications and with relational databases accessed via the JDBC API because of its origin in Sun Microsystems' best practice guidelines ("Core J2EE Patterns") for that platform. Advantages The advantage of using data access objects is the relatively simple and rigorous separation between two important parts of an application that can and should know almost nothing of each other, and which can be expected to evolve frequently and independently. Changing business logic can rely on the same DAO interface, while changes to persistence logic do not affect DAO clients as long as the interface remains correctly implemented.