Welcome!

SOA & WOA Authors: Yeshim Deniz, Elizabeth White, Liz McMillan, John Savageau, Plutora Blog

Related Topics: SOA & WOA

SOA & WOA: Article

Introducing SOA Design Patterns

The SOA community collaborates to produce a master pattern catalog dedicated to SOA

Fundamental Service Design
At the most basic level of service design, the established "separation of concerns" theory needs to be applied as part of a process whereby a larger problem is decomposed in a way that we can clearly identify how corresponding solution logic should be partitioned into services. To accomplish this, a series of base patterns have emerged to form a fundamental pattern language that can serve as the basis of a primitive design process.

Examples of these basic patterns are Functional Decomposition and Service Encapsulation, both of which help determine what type of logic does and does not belong in a service. Additional patterns, like Agnostic Context and Non-Agnostic Context provide criteria that help determine whether certain kinds of logic are deemed sufficiently agnostic to be put into a reusable or multi-purpose service (see Figure 3).

Service Implementation Design and Governance
A key pattern frequently applied to the initial design of service architecture is the Service Façade. Inspired by the Façade pattern created by the Gang of Four, this pattern wedges a component between the service contract and the core service logic to establish a point of abstraction. This is really nothing new, but it does establish an architectural foundation that can be leveraged by other more specialized SOA patterns.

For example, Service Decomposition (one of the service governance patterns) allows a coarse-grained service to be split up subsequent to its deployment. Additional governance patterns, such as Proxy Capability and Distributed Capability (see Figure 4), help ensure that this decomposition of one service into two or more does not impact the contract (technical interface) of the original service, thereby also avoiding impact to that service's consumer programs.

Other patterns, such as Legacy Wrapper, Redundant Implementation, Service Refactoring, and Service Data Replication, can be selectively used to address various implementation and scalability-related requirements, while maintaining the overall flexibility required for services to be repeatedly composed and extended, as required.

Service Contract Design and Governance
A key design pattern that helps increase the longevity of service contracts (to postpone versioning requirements) is Contract Denormalization. This pattern essentially explains how capabilities with overlapping functional scopes can be added to a service contract without negatively impacting service or inventory architectures. This results in the contract's technical interface exposing similar functions at different levels of granularity, allowing the same contract to facilitate the requirements of different types of consumers.

Alternatively, multiple groups of consumers can be accommodated by the Concurrent Contracts pattern that describes how entirely separate contracts can be created for the same underlying service logic. Security restrictions or a need to split up policy alternatives for reasons of governance can also result in the requirement to employ multiple service contracts. This pattern also benefits from the existence of a service façade that can be positioned to coordinate incoming and outgoing data exchanges across multiple contracts but with a single body of core service logic.

Part of these governance patterns includes various contract versioning design techniques to minimize the impact of having to introduce new contract versions or support multiple versions of the same contract. Some governance patterns are reactive because they help solve unexpected governance-related design issues, while others are preventative in that they can be applied prior to the initial deployment of a service in order to build in additional flexibility that allows the service to be more easily governed and extended over time.

Patterns for Service Composition and Communication
As an aggregate set of services, a service composition establishes its own unique architecture encompassing the individual service architectures of the composition members and introducing additional design requirements focused on inter-service communication and runtime activity management. It's therefore no surprise that many design patterns have emerged to address composition-related design issues.

There are several key design patterns that establish the mechanics behind inter-service communication. Due to the popularity of building services as Web Services, several of these design patterns are based on messaging, and some are focused solely on asynchronous messaging. For example, the Asynchronous Queuing design pattern establishes a central queue to allow services to overcome availability issues and increase the overall robustness of asynchronous data exchange.

The marriage of SOA and EDA has resulted in the Event-Driven Messaging pattern that enables publish-and-subscribe functionality between services over extended periods. This can go hand-in-hand with the use of the Service Agent pattern that introduces an additional event-driven dimension into composition architecture by allowing you to defer various types of cross-cutting logic to transparent agents that intercept and forward messages at runtime (see Figure 5).

The Intermediate Routing pattern takes this a step further by providing intelligent agent-based message routing that can also help increase the overall scalability of services and compositions.

Very much related to supporting service messaging and the hosting and execution of service compositions as a whole is the Enterprise Service Bus compound pattern. As shown in Figure 6, this pattern establishes an environment comprised of multiple other patterns, such as the aforementioned Intermediate Routing and Asynchronous Queuing patterns in addition to the Broker pattern (that in itself is also a compound pattern that represents a set of individual transformation patterns).

Note that there are additional design patterns associated with the Enterprise Service Bus compound pattern, several of which are classified as optional extensions to a core model. Other design patterns that tie into service composition architecture include Cross-Service Transaction, Composition Autonomy, Reliable Messaging, and Agnostic Sub-Controller.

More Stories By Thomas Erl

Thomas Erl is a best-selling IT author and founder of Arcitura Education Inc., a global provider of vendor-neutral educational services and certification that encompasses the Cloud Certified Professional (CCP) and SOA Certified Professional (SOACP) programs from CloudSchool.com™ and SOASchool.com® respectively. Thomas has been the world's top-selling service technology author for nearly a decade and is the series editor of the Prentice Hall Service Technology Series from Thomas Erl, as well as the editor of the Service Technology Magazine. With over 175,000 copies in print world-wide, his eight published books have become international bestsellers and have been formally endorsed by senior members of many major IT organizations and academic institutions. To learn more, visit: www.thomaserl.com

Comments (0)

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


@ThingsExpo Stories
The Industrial Internet revolution is now underway, enabled by connected machines and billions of devices that communicate and collaborate. The massive amounts of Big Data requiring real-time analysis is flooding legacy IT systems and giving way to cloud environments that can handle the unpredictable workloads. Yet many barriers remain until we can fully realize the opportunities and benefits from the convergence of machines and devices with Big Data and the cloud, including interoperability, data security and privacy.
SYS-CON Media announced that Cisco, a worldwide leader in IT that helps companies seize the opportunities of tomorrow, has launched a new ad campaign in Cloud Computing Journal. The ad campaign, a webcast titled 'Is Your Data Center Ready for the Application Economy?', focuses on the latest data center networking technologies, including SDN or ACI, and how customers are using SDN and ACI in their organizations to achieve business agility. The Cisco webcast is available on-demand.
IoT is still a vague buzzword for many people. In his session at @ThingsExpo, Mike Kavis, Vice President & Principal Cloud Architect at Cloud Technology Partners, discussed the business value of IoT that goes far beyond the general public's perception that IoT is all about wearables and home consumer services. He also discussed how IoT is perceived by investors and how venture capitalist access this space. Other topics discussed were barriers to success, what is new, what is old, and what the future may hold. Mike Kavis is Vice President & Principal Cloud Architect at Cloud Technology Pa...
Dale Kim is the Director of Industry Solutions at MapR. His background includes a variety of technical and management roles at information technology companies. While his experience includes work with relational databases, much of his career pertains to non-relational data in the areas of search, content management, and NoSQL, and includes senior roles in technical marketing, sales engineering, and support engineering. Dale holds an MBA from Santa Clara University, and a BA in Computer Science from the University of California, Berkeley.
The Internet of Things (IoT) is rapidly in the process of breaking from its heretofore relatively obscure enterprise applications (such as plant floor control and supply chain management) and going mainstream into the consumer space. More and more creative folks are interconnecting everyday products such as household items, mobile devices, appliances and cars, and unleashing new and imaginative scenarios. We are seeing a lot of excitement around applications in home automation, personal fitness, and in-car entertainment and this excitement will bleed into other areas. On the commercial side, m...
The Internet of Things (IoT) promises to evolve the way the world does business; however, understanding how to apply it to your company can be a mystery. Most people struggle with understanding the potential business uses or tend to get caught up in the technology, resulting in solutions that fail to meet even minimum business goals. In his session at @ThingsExpo, Jesse Shiah, CEO / President / Co-Founder of AgilePoint Inc., showed what is needed to leverage the IoT to transform your business. He discussed opportunities and challenges ahead for the IoT from a market and technical point of vie...
Things are being built upon cloud foundations to transform organizations. This CEO Power Panel at 15th Cloud Expo, moderated by Roger Strukhoff, Cloud Expo and @ThingsExpo conference chair, addressed the big issues involving these technologies and, more important, the results they will achieve. Rodney Rogers, chairman and CEO of Virtustream; Brendan O'Brien, co-founder of Aria Systems, Bart Copeland, president and CEO of ActiveState Software; Jim Cowie, chief scientist at Dyn; Dave Wagstaff, VP and chief architect at BSQUARE Corporation; Seth Proctor, CTO of NuoDB, Inc.; and Andris Gailitis, C...
SYS-CON Events announced today that CodeFutures, a leading supplier of database performance tools, has been named a “Sponsor” of SYS-CON's 16th International Cloud Expo®, which will take place on June 9–11, 2015, at the Javits Center in New York, NY. CodeFutures is an independent software vendor focused on providing tools that deliver database performance tools that increase productivity during database development and increase database performance and scalability during production.
Today’s enterprise is being driven by disruptive competitive and human capital requirements to provide enterprise application access through not only desktops, but also mobile devices. To retrofit existing programs across all these devices using traditional programming methods is very costly and time consuming – often prohibitively so. In his session at @ThingsExpo, Jesse Shiah, CEO, President, and Co-Founder of AgilePoint Inc., discussed how you can create applications that run on all mobile devices as well as laptops and desktops using a visual drag-and-drop application – and eForms-buildi...
"People are a lot more knowledgeable about APIs now. There are two types of people who work with APIs - IT people who want to use APIs for something internal and the product managers who want to do something outside APIs for people to connect to them," explained Roberto Medrano, Executive Vice President at SOA Software, in this SYS-CON.tv interview at Cloud Expo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
Performance is the intersection of power, agility, control, and choice. If you value performance, and more specifically consistent performance, you need to look beyond simple virtualized compute. Many factors need to be considered to create a truly performant environment. In his General Session at 15th Cloud Expo, Harold Hannon, Sr. Software Architect at SoftLayer, discussed how to take advantage of a multitude of compute options and platform features to make cloud the cornerstone of your online presence.
SYS-CON Media announced that Splunk, a provider of the leading software platform for real-time Operational Intelligence, has launched an ad campaign on Big Data Journal. Splunk software and cloud services enable organizations to search, monitor, analyze and visualize machine-generated big data coming from websites, applications, servers, networks, sensors and mobile devices. The ads focus on delivering ROI - how improved uptime delivered $6M in annual ROI, improving customer operations by mining large volumes of unstructured data, and how data tracking delivers uptime when it matters most.
Almost everyone sees the potential of Internet of Things but how can businesses truly unlock that potential. The key will be in the ability to discover business insight in the midst of an ocean of Big Data generated from billions of embedded devices via Systems of Discover. Businesses will also need to ensure that they can sustain that insight by leveraging the cloud for global reach, scale and elasticity.
Advanced Persistent Threats (APTs) are increasing at an unprecedented rate. The threat landscape of today is drastically different than just a few years ago. Attacks are much more organized and sophisticated. They are harder to detect and even harder to anticipate. In the foreseeable future it's going to get a whole lot harder. Everything you know today will change. Keeping up with this changing landscape is already a daunting task. Your organization needs to use the latest tools, methods and expertise to guard against those threats. But will that be enough? In the foreseeable future attacks w...
As enterprises move to all-IP networks and cloud-based applications, communications service providers (CSPs) – facing increased competition from over-the-top providers delivering content via the Internet and independently of CSPs – must be able to offer seamless cloud-based communication and collaboration solutions that can scale for small, midsize, and large enterprises, as well as public sector organizations, in order to keep and grow market share. The latest version of Oracle Communications Unified Communications Suite gives CSPs the capability to do just that. In addition, its integration ...
SYS-CON Events announced today that ActiveState, the leading independent Cloud Foundry and Docker-based PaaS provider, has been named “Silver Sponsor” of SYS-CON's DevOps Summit New York, which will take place June 9-11, 2015, at the Javits Center in New York City, NY. ActiveState believes that enterprises gain a competitive advantage when they are able to quickly create, deploy and efficiently manage software solutions that immediately create business value, but they face many challenges that prevent them from doing so. The Company is uniquely positioned to help address these challenges thro...
“The age of the Internet of Things is upon us,” stated Thomas Svensson, senior vice-president and general manager EMEA, ThingWorx, “and working with forward-thinking companies, such as Elisa, enables us to deploy our leading technology so that customers can profit from complete, end-to-end solutions.” ThingWorx, a PTC® (Nasdaq: PTC) business and Internet of Things (IoT) platform provider, announced on Monday that Elisa, Finnish provider of mobile and fixed broadband subscriptions, will deploy ThingWorx® platform technology to enable a new Elisa IoT service in Finland and Estonia.
From telemedicine to smart cars, digital homes and industrial monitoring, the explosive growth of IoT has created exciting new business opportunities for real time calls and messaging. In his session at @ThingsExpo, Ivelin Ivanov, CEO and Co-Founder of Telestax, shared some of the new revenue sources that IoT created for Restcomm – the open source telephony platform from Telestax. Ivelin Ivanov is a technology entrepreneur who founded Mobicents, an Open Source VoIP Platform, to help create, deploy, and manage applications integrating voice, video and data. He is the co-founder of TeleStax, a...
We certainly live in interesting technological times. And no more interesting than the current competing IoT standards for connectivity. Various standards bodies, approaches, and ecosystems are vying for mindshare and positioning for a competitive edge. It is clear that when the dust settles, we will have new protocols, evolved protocols, that will change the way we interact with devices and infrastructure. We will also have evolved web protocols, like HTTP/2, that will be changing the very core of our infrastructures. At the same time, we have old approaches made new again like micro-services...
The Internet of Things is a misnomer. That implies that everything is on the Internet, and that simply should not be - especially for things that are blurring the line between medical devices that stimulate like a pacemaker and quantified self-sensors like a pedometer or pulse tracker. The mesh of things that we manage must be segmented into zones of trust for sensing data, transmitting data, receiving command and control administrative changes, and peer-to-peer mesh messaging. In his session at @ThingsExpo, Ryan Bagnulo, Solution Architect / Software Engineer at SOA Software, focused on desi...