Architectural pattern

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An architectural pattern is a general, reusable resolution to a commonly occurring problem in software architecture within a given context. [1] The architectural patterns address various issues in software engineering, such as computer hardware performance limitations, high availability and minimization of a business risk. Some architectural patterns have been implemented within software frameworks. There are two main categories of architectural patterns: monolithic and distributed. [2]

Contents

The use of the word "pattern" in the software industry was influenced by similar concepts as expressed in traditional architecture, such as Christopher Alexander's A Pattern Language (1977) which discussed the practice in terms of establishing a pattern lexicon, prompting the practitioners of computer science to contemplate their own design lexicon.

Usage of this metaphor within the software engineering profession became commonplace after the publication of Design Patterns (1994) by Erich Gamma, Richard Helm, Ralph Johnson, and John Vlissides—now commonly known as the "Gang of Four"—coincident with the early years of the public Internet, marking the onset of complex software systems "eating the world" [3] and the corresponding need to codify the rapidly sprawling world of software development at the deepest possible level, while remaining flexible and adaptive.

Architectural patterns are similar to software design patterns but have a broader scope.

Definition

Even though an architectural pattern conveys an image of a system, it is not an architecture. An architectural pattern is a concept that solves and delineates some essential cohesive elements of a software architecture. Countless different architectures may implement the same pattern and share the related characteristics. Patterns are often defined as "strictly described and commonly available". [4] [5]

Architectural style

Following traditional building architecture, a software architectural style is a specific method of construction, characterized by the features that make it notable.

An architectural style defines: a family of systems in terms of a pattern of structural organization; a vocabulary of components and connectors, with constraints on how they can be combined. [6]

An architectural style is a named collection of architectural design decisions that (1) are applicable in a given development context, (2) constrain architectural design decisions that are specific to a particular system within that context, and (3) elicit beneficial qualities in each resulting system. [1]

Some treat architectural patterns and architectural styles as the same, [7] some treat styles as specializations of patterns. What they have in common is both patterns and styles are idioms for architects to use, they "provide a common language" [7] or "vocabulary" [6] with which to describe classes of systems.

The main difference is that a pattern can be seen as a solution to a problem, while a style is more general and does not require a problem to solve for its appearance.

Analysis

Software is managed by its problem space into which solutions may be applied. The table below shows how software is considered across various problem spaces, defined by a sub-domain and addressed with corresponding software design patterns and solution patterns. Sub-domains can be incorporated into the analysis of other sub-domains, for example, solving an Artificial Intelligence problem is first approached as a Data Architecture problem.

Sub-domain areaArchitecture patternSoftware design patternsSolution patternsRelated patterns
Data integration/SOA
  • One-way
  • Synchronous request/response
  • Basic callback
  • Claim check
Data architecture
  • Custom applications databases
  • Packaged application databases
Analytics and business intelligence
  • Transactional reporting
  • Operational analytics
  • Business analytics
  • Predictive analytics
  • Prescriptive analytics
  • Streaming analytics
  • Data science and advanced analytics
  • NLP
  • Transactional reporting data access
  • Operational reporting data access
  • Analytical reporting data access
  • Analytical dashboard data access
  • Operational dashboard data access
  • Data mining
  • ETL
  • EAI
  • TDS
  • Operational data store
  • Data mart
Master data management
  • Master data hub
  • Master data replication
  • Master data services
  • Master data synchronization
Data modeling
  • Modeling standards
  • Naming conventions
Artificial intelligence

Examples

Some examples of architectural patterns:

See also

Related Research Articles

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<span class="mw-page-title-main">Software architecture</span> High level structures of a software system

Software architecture is the set of structures needed to reason about a software system and the discipline of creating such structures and systems. Each structure comprises software elements, relations among them, and properties of both elements and relations.

The facade pattern is a software design pattern commonly used in object-oriented programming. Analogous to a façade in architecture, it is an object that serves as a front-facing interface masking more complex underlying or structural code. A facade can:

<span class="mw-page-title-main">Data model</span> Abstract model

A data model is an abstract model that organizes elements of data and standardizes how they relate to one another and to the properties of real-world entities. For instance, a data model may specify that the data element representing a car be composed of a number of other elements which, in turn, represent the color and size of the car and define its owner.

In software engineering, a design pattern describes a relatively small, well-defined aspect of a computer program in terms of how to write the code.

Software design is the process of conceptualizing how a software system will work before it is implemented or modified. Software design also refers to the direct result of the design process – the concepts of how the software will work which consists of both design documentation and undocumented concepts.

In computer science, separation of concerns is a design principle for separating a computer program into distinct sections. Each section addresses a separate concern, a set of information that affects the code of a computer program. A concern can be as general as "the details of the hardware for an application", or as specific as "the name of which class to instantiate". A program that embodies SoC well is called a modular program. Modularity, and hence separation of concerns, is achieved by encapsulating information inside a section of code that has a well-defined interface. Encapsulation is a means of information hiding. Layered designs in information systems are another embodiment of separation of concerns.

A modeling language is any artificial language that can be used to express data, information or knowledge or systems in a structure that is defined by a consistent set of rules. The rules are used for interpretation of the meaning of components in the structure of a programming language.

In software engineering, service-oriented architecture (SOA) is an architectural style that focuses on discrete services instead of a monolithic design. SOA is a good choice for system integration. By consequence, it is also applied in the field of software design where services are provided to the other components by application components, through a communication protocol over a network. A service is a discrete unit of functionality that can be accessed remotely and acted upon and updated independently, such as retrieving a credit card statement online. SOA is also intended to be independent of vendors, products and technologies.

REST is a software architectural style that was created to guide the design and development of the architecture for the World Wide Web. REST defines a set of constraints for how the architecture of a distributed, Internet-scale hypermedia system, such as the Web, should behave. The REST architectural style emphasises uniform interfaces, independent deployment of components, the scalability of interactions between them, and creating a layered architecture to promote caching to reduce user-perceived latency, enforce security, and encapsulate legacy systems.

<span class="mw-page-title-main">Systems architect</span>

The systems architect is an information and communications technology professional. Systems architects define the architecture of a computerized system in order to fulfill certain requirements. Such definitions include: a breakdown of the system into components, the component interactions and interfaces, and the technologies and resources to be used in its design and implementation.

Object-oriented analysis and design (OOAD) is a technical approach for analyzing and designing an application, system, or business by applying object-oriented programming, as well as using visual modeling throughout the software development process to guide stakeholder communication and product quality.

Domain engineering, is the entire process of reusing domain knowledge in the production of new software systems. It is a key concept in systematic software reuse and product line engineering. A key idea in systematic software reuse is the domain. Most organizations work in only a few domains. They repeatedly build similar systems within a given domain with variations to meet different customer needs. Rather than building each new system variant from scratch, significant savings may be achieved by reusing portions of previous systems in the domain to build new ones.

General Responsibility Assignment Software Patterns, abbreviated GRASP, is a set of "nine fundamental principles in object design and responsibility assignment" first published by Craig Larman in his 1997 book Applying UML and Patterns.

Software analysis patterns or analysis patterns in software engineering are conceptual models, which capture an abstraction of a situation that can often be encountered in modelling. An analysis pattern can be represented as "a group of related, generic objects (meta-classes) with stereotypical attributes, behaviors, and expected interactions defined in a domain-neutral manner."

Naked objects is an architectural pattern used in software engineering. It is defined by three principles:

Domain-driven design (DDD) is a major software design approach, focusing on modeling software to match a domain according to input from that domain's experts. DDD is against the idea of having a single unified model; instead it divides a large system into bounded contexts, each of which have their own model.

A communication protocol is a system of rules that allows two or more entities of a communications system to transmit information via any variation of a physical quantity. The protocol defines the rules, syntax, semantics, and synchronization of communication and possible error recovery methods. Protocols may be implemented by hardware, software, or a combination of both.

In software engineering, a microservice architecture is an architectural pattern that arranges an application as a collection of loosely coupled, fine-grained services, communicating through lightweight protocols. One of its goals is that teams can develop and deploy their services independently of others. This is achieved by the reduction of several dependencies in the code base, allowing developers to evolve their services with limited restrictions from users, and for additional complexity to be hidden from users. As a consequence, organizations are able to develop software with fast growth and size, as well as use off-the-shelf services more easily. Communication requirements are reduced. These benefits come at a cost to maintaining the decoupling. So, microservice architecture can be a good choice only if the application is too complex to manage as a monolith. Interfaces need to be designed carefully and treated as a public API. One technique that is used is having multiple interfaces on the same service, or multiple versions of the same service, so as to not disrupt existing users of the code.

References

  1. 1 2 Taylor, R.N.; Medvidović, N.; Dashofy, E.M. (2009). Software architecture: Foundations, Theory and Practice. Wiley. ISBN   9780470167748.
  2. 1 2 3 4 5 Fundamentals of Software Architecture: An Engineering Approach. O'Reilly Media. 2020. ISBN   978-1492043454.
  3. Andreessen, Marc (20 August 2011). "Why Software Is Eating The World". The Wall Street Journal . Retrieved 25 April 2020.
  4. Chang, Chih-Hung; Lu, Chih-Wei; Lin, Chih-Hao; Yang, Ming-Feng; Tsai, Ching-Fu (June 2008). "An Experience of Applying Pattern-based Software Framework to Improve the Quality of Software Development: 4. The Design and Implementation of OS2F". Journal of Software Engineering Studies, Vol. 2, No. 6. the Third Taiwan Conference on Software Engineering (TCSE07). pp. 185–194. Archived from the original on 2011-09-22. Retrieved 2012-05-16. Furthermore, patterns are often defined as something "strictly described and commonly available". For example, layered architecture is a call-and-return style, when it defines an overall style to interact.
  5. "Architectural Patterns: Definition". AAHN INFOTECH (INDIA) PVT. LTD. Archived from the original on 2012-06-23. Retrieved 2012-05-16. Even though an architectural pattern conveys an image of a system, it is not an architecture as such. An architectural pattern is rather a concept that solves and delineates some essential cohesive elements of a software architecture. Countless different architectures may implement the same pattern and thereby share the related characteristics. Furthermore, patterns are often defined as something "strictly described and commonly available".
  6. 1 2 Shaw, M.; Garlan, D. (1996). Software architecture : perspectives on an emerging discipline. Prentice Hall. ISBN   9780131829572.
  7. 1 2 "Ch. 3: Architectural Patterns and Styles". Microsoft Application Architecture Guide (2nd ed.). Microsoft Press. October 2009. ISBN   9780735627109.

Bibliography