Service-orientation design principles are proposed principles for developing the solution logic of services within

service-oriented architecture In software engineering, service-oriented architecture (SOA) is an architectural style that focuses on discrete services instead of a monolithic design. By consequence, it is also applied in the field of software design where services are provide ...

s (SOA).Wojciech Cellary, Sergiusz Strykowsk
E-Government Based on Cloud Computing and Service-Oriented Architecture
Date Accessed: 11 April 2010.

Overview

The success of software development based on any particular

design paradigm A design is a plan or specification for the construction of an object or system or for the implementation of an activity or process or the result of that plan or specification in the form of a prototype, product, or process. The verb ''to design'' ...

is never assured. Software developed under the service-oriented design paradigm carries even greater risks. This is because a service-oriented architecture usually spans multiple business areas and requires considerable initial analysis. Therefore, SOA developed without concrete guidelines is very likely to fail.Jon Brodki
SOA failures traced to people, process issues
Date accessed: 8 April 2010. To ensure that the move towards service-orientation is a positive change that delivers on its promised benefits, it is helpful to adopt a set of rules.Gero Vermaa
Top 10 SOA Pitfalls
Date accessed: 8 April 2010. The service-orientation design principles may be broadly categorized as follows, following

Thomas Erl Thomas Erl (born 1967) is a Canadian author, and public speaker known for major contributions to the field of service-oriented architecture. Author of eight books on Service Orientation, Erl defined eight widely accepted principles of service ...

's, ''SOA Principles of Service Design'':

(2008)
SOA Principles of Service Design
. Prentice Hall. Michael Pouli
Evolution of principles of Service Orientation, part 1
Date accessed: 12 April 2010. *

Standardized service contract The standardized service contract is a software design principle applied within the service-orientation design paradigm to guarantee that service contracts within a service inventory (enterprise or domain) adhere to the same set of design standards. ...

Service loose coupling Service may refer to: Activities * Administrative service, a required part of the workload of university faculty * Civil service, the body of employees of a government * Community service, volunteer service for the benefit of a community or a p ...

Service abstraction Service abstraction is a design principle that is applied within the service-orientation design paradigm so that the information published in a service contract is limited to what is required to effectively utilize the service The service contract s ...

* Service reusability * Service autonomy * Service statelessness * Service discoverability * Service composability It is the application of these design principles that create technology independent services and hence provide interoperability in the long term.David Webbe
Services as Web Services: "Are We There Yet?"How Web Service Technology Stacks Alone Cannot Fulfill the Goals of SOA
Date Accessed: 11 April 2010. These design principles serve as a guideline for identifying services.

Strategic goals

The application of these principles helps in attaining the underlying goals linked with the adoption of service-orientation in the first place. These goals are strategic in nature i.e. long term and look beyond the immediate needsThe immediate needs are those that are linked with automating a particular business process e.g. invoice processing while long-term requirements are those that look beyond the current requirements and are usually spread across multiple business processes of an organization. These strategic objectives could be summarized into the following seven goals & benefits:Sadi Melbouc

Date Accessed: 10 April 2010. * Increased intrinsic interoperability * Increased federation * Increased vendor diversification options * Increased business and technology alignment * Increased ROI * Increased organizational agility * Reduced IT burden Each of the above goals and benefits directly helps towards developing an agile organizationAn agile organization within the context of IT world is one that can quickly respond to its business requirements while using much of its existing resources. that can quickly respond to the ever-changing market conditions with reduced efforts and time.

Characteristics

The service-orientation design principles help in distinguishing a service-oriented solutionA solution that is based on service-orientation design paradigm and is made up of services. from a traditional object-oriented solution by promoting distinct design characteristics. The presence of these characteristics in a service-oriented solution greatly improves the chances of realizing the aforementioned goals and benefits. Erl has identified four service-orientation characteristics as follows:Erl et al, (2009)
SOA Design Patterns
. Prentice Hall. * Vendor-neutral * Business-driven * Enterprise-centric * Composition-centric A vendor-neutral service-oriented solution helps to evolve the underlying technology architecture in response to ever changing business requirements. By not being dependent on a particular vendor, any aging infrastructure could be replaced by more efficient technologies without the need for redesigning the whole solution from scratch. This also helps in creating a heterogeneous technology environment where particular business automation requirements are fulfilled by specific technologies. Within a SOA, the development of solution logic is driven by the needs of the business and is designed in a manner that focuses on the long-term requirements of the business. As a result, the technology architecture is more aligned with the business needs. Unlike traditional silo-based application development, a SOA takes into account the requirements of either the whole of the enterprise or at least some considerable part of it. As a result, the developed services are interoperable and reusable across the different segments of the enterprise. A service-oriented solution enables to deal with new and changing requirements, within a reduced amount of time, by making use of existing services. The services are designed in a manner so that they can be recomposed i.e. become a part of different solutions.

Application

The service-orientation design principles are applied during the service-oriented analysis and design process. The extent to which each of these principles could be applied is always relative and needs to be weighed against the overall goals and objectives of an organization as well as the time constraints. One important factor that needs to be kept in mind is that it is not just the application of these design principles alone but the consistent application that guarantees the realization of the service-orientation design goals linked with the adoption of service-orientation. This is because services are an enterprise resource, i.e. giving the confidence that they conform to certain standards and could be reused within multiple solutions, so in order to remain such a resource, they must emerge from a process to which these principles have been applied consistently, as an inconsistent application would result in services that are not compatible with each other, resulting in loss of the fundamental service-orientation design characteristics.

References

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Overview

Strategic goals

Characteristics

Application

See also

References

Further reading