Design Patterns Courses Online

Scala is programming language It is a object-based language. Scala is mainly influenced by ML, Java and Erlang. Scala follows a programming paradigm of concurrent computing, functional programming and imperative programming. Scala is developed by Martin Odersky and École polytechnique fédérale de Lausanne. It is designed by Martin Odersky

A software design pattern is a general reusable solution to a problem that repeats itself in software design within a given context. It is not a finished design that can be transformed directly into code, and constitutes a description or template for a problem that can be used in many different situations. Software design patterns are formalized best practices that have to be implemented in applications.[1] A part of the software design patterns are object-oriented design patterns that show relationships and interactions between classes or objects without specifying the final application objects that are involved. Patterns that imply object-orientation or more generally mutable state, are not as applicable in functional programming languages.

If you remember, software engineers speak a common language called UML. And if we use this analogy of language, then design patterns are the common stories our culture shares, like for instance fairy tales. They are stories about commonly occurring problems in software design and their solutions. And as young children learn about good and evil from fairy tales, beginning software engineers learn about good design (design patterns) and bad design (anti-patterns).

A design pattern describes a problem that occurs over the time in a specific context and it pairs the problem to a solution. Usually these pairs of problem-solutions can be used in larger contexts as well. The solution is usually a general term and the details are left with those who apply the pattern or is elaborated by other low-level patterns. The solution has different definitions in different contexts for example, in production fields solution can be a new (quite simple or very complex) thing or an artifact, and in practical fields such as education a solution could be a method rather than a thing. Also, the important fact about the design pattern is that the body of the problem should include a rationale (drawing on research, theory, experience, etc.). When the patterns are organized and connected to each other into a comprehensive and sequential order it is called Pattern Language.

Software design patterns are abstractions that help structure system designs. While not new, since the concept was already described by Christopher Alexander in its architectural theories, it only gathered some traction in programming due to the publication of Design Patterns: Elements of Reusable Object-Oriented Software book in October 1994 by Erich Gamma, Richard Helm, Ralph Johnson and John Vlissides, known as the Gang of Four (GoF), that identifies and describes 23 classic software design patterns.

Programming for real-time environments is hard and needs a good understanding of the complete system, hardware as well as software. In the ideal case, every part of the system is well described and easily understandable, but the real world seldom allows this ideal situation. Therefore, the system should be robust against the uncertainties in the system. design patterns are a useful support for all designers: they are generalized solutions to commonly occurring problems, based on experience of what has worked already in the past in a large number of systems. Patterns are also appropriate to create portable code that may be reused and adapted in several applications.