Comments
yourfanat wrote: I am using another tool for Oracle developers - dbForge Studio for Oracle. This IDE has lots of usefull features, among them: oracle designer, code competion and formatter, query builder, debugger, profiler, erxport/import, reports and many others. The latest version supports Oracle 12C. More information here.
Cloud Expo on Google News
SYS-CON.TV

2008 West
DIAMOND SPONSOR:
Data Direct
SOA, WOA and Cloud Computing: The New Frontier for Data Services
PLATINUM SPONSORS:
Red Hat
The Opening of Virtualization
GOLD SPONSORS:
Appsense
User Environment Management – The Third Layer of the Desktop
Cordys
Cloud Computing for Business Agility
EMC
CMIS: A Multi-Vendor Proposal for a Service-Based Content Management Interoperability Standard
Freedom OSS
Practical SOA” Max Yankelevich
Intel
Architecting an Enterprise Service Router (ESR) – A Cost-Effective Way to Scale SOA Across the Enterprise
Sensedia
Return on Assests: Bringing Visibility to your SOA Strategy
Symantec
Managing Hybrid Endpoint Environments
VMWare
Game-Changing Technology for Enterprise Clouds and Applications
Click For 2008 West
Event Webcasts

2008 West
PLATINUM SPONSORS:
Appcelerator
Get ‘Rich’ Quick: Rapid Prototyping for RIA with ZERO Server Code
Keynote Systems
Designing for and Managing Performance in the New Frontier of Rich Internet Applications
GOLD SPONSORS:
ICEsoft
How Can AJAX Improve Homeland Security?
Isomorphic
Beyond Widgets: What a RIA Platform Should Offer
Oracle
REAs: Rich Enterprise Applications
Click For 2008 Event Webcasts
SOA Pattern of the Week (#1): Service Façade
Functional and behavioral changes to core business logic

One of the fundamental goals when designing service-oriented solutions is to attain a reduced degree of coupling between services, thereby increasing the freedom and flexibility with which services can be individually evolved. Achieving the right level of coupling "looseness" is most often considered a design issue that revolves around the service contract and the consumer programs that form dependencies upon it.

However, for the service architect there are opportunities to establish intermediate layers of abstraction within the service implementation that further foster reduced levels of coupling between its internal moving parts so as to accommodate the evolution and governance of the service itself. These intermediate abstraction layers are created by the application of Service Façade, a design pattern focused on intra-service design.

When designing a service, there are several negative coupling types you need to look out for. Contract-to-logic coupling, for example, results in a service contract that is derived from (and therefore may have formed dependencies upon) the underlying service logic, which makes the contract subject to change whenever the logic changes. The result is, predictably, a cascading effect whereby all service consumers are impacted (usually negatively) by the changes.

Service Façade can help avoid these situations by establishing an intermediary processing layer in between the core service logic and the service contract. The façade logic allows the service contract to remain decoupled from the underlying logic and further shields it from changes to the core business logic. This applies to both functional and behavioral changes, the latter of which may (often inadvertently) come about as a result of applying the Service Refactoring pattern. The façade layer can compensate for internal changes so that the service contract does not need to be modified as a result of the changes and/or the behavior of the functionality expressed in the contract is also not affected. In both cases, the service can evolve internally while existing service consumers remain protected from any potential side-effects.

Another scenario that can be effectively managed through the application of this pattern is when a single body of core service logic requires multiple contracts (a situation that actually pertains to another pattern called Concurrent Contracts). In this case, a separate service façade component can be created for each service contract, thereby retaining a clean abstraction of core service logic from the contract layer. This avoids having to augment and bloat the core service logic over time in order to accommodate different contracts and can further leverage the aforementioned benefits of functional and behavioral compensation when that logic is subject to functional change or refactoring efforts.

The Service Façade pattern can result in an elegant service architecture with clean layers of abstraction, but it can also impose extra processing overhead that naturally comes with increasing the physical distribution of service logic. The fact that service logic ends up being more distributed can also be perceived as increasing the complexity of the service design as well. Carefully minding the type of logic placed in façade layers will help mitigate these issues.

Overall, though, the intelligent and regulated application of this pattern can result in an effective separation of intra-service processing responsibilities, which brings with it numerous governance benefits that can accommodate the long-term evolution of the service and further help to preserve on-going relationships formed with service consumer programs.

The SOA Pattern of the Week series is comprised of original content and insights provided courtesy of the authors and contributors of the SOAPatterns.org community site and the book "SOA Design Patterns" (Erl et al., ISBN: 0136135161, Prentice Hall, 2009), the latest title in the "Prentice Hall Service-Oriented Computing Series from Thomas Erl" (www.soabooks.com). Copyright 2009 SOA Systems Inc.

About 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

About Herbjorn Wilhelmsen
Herbjorn Wilhelmsen is an Architect and Senior Consultant at Objectware in Stockholm, Sweden. His main focus areas include service-oriented architecture, Web services and business architecture. Herbjörn has many years of industry experience working as a developer, development manager, architect and teacher in several fields of operations, such as telecommunications, marketing, payment industry, health care and public services. He is active as an author in the Prentice Hall Service-Oriented Computing Series from Thomas Erl and has contributed design patterns to SOAPatterns.org. He leads the Business-to-IT group in the Swedish chapter of the International Association of Software Architects, which performs a comparative study of a number of business architecture methodologies. Herbjörn holds a Bachelor of Science from Stockholm University.

In order to post a comment you need to be registered and logged in.

Register | Sign-in

Reader Feedback: Page 1 of 1

Latest AJAXWorld RIA Stories
"Our strategy is to focus on the hyperscale providers - AWS, Azure, and Google. Over the last year we saw that a lot of developers need to learn how to do their job in the cloud and we see this DevOps movement that we are catering to with our content," stated Alessandro Fasan, He...
Deep learning has been very successful in social sciences and specially areas where there is a lot of data. Trading is another field that can be viewed as social science with a lot of data. With the advent of Deep Learning and Big Data technologies for efficient computation, we a...
Data is the fuel that drives the machine learning algorithmic engines and ultimately provides the business value. In his session at Cloud Expo, Ed Featherston, a director and senior enterprise architect at Collaborative Consulting, discussed the key considerations around qualit...
Detecting internal user threats in the Big Data eco-system is challenging and cumbersome. Many organizations monitor internal usage of the Big Data eco-system using a set of alerts. This is not a scalable process given the increase in the number of alerts with the accelerating gr...
@DevOpsSummit New York 2018, colocated with CloudEXPO | DXWorldEXPO New York 2018 will be held November 11-13, 2018, in New York City. From showcase success stories from early adopters and web-scale businesses, DevOps is expanding to organizations of all sizes, including the worl...
Subscribe to the World's Most Powerful Newsletters
Subscribe to Our Rss Feeds & Get Your SYS-CON News Live!
Click to Add our RSS Feeds to the Service of Your Choice:
Google Reader or Homepage Add to My Yahoo! Subscribe with Bloglines Subscribe in NewsGator Online
myFeedster Add to My AOL Subscribe in Rojo Add 'Hugg' to Newsburst from CNET News.com Kinja Digest View Additional SYS-CON Feeds
Publish Your Article! Please send it to editorial(at)sys-con.com!

Advertise on this site! Contact advertising(at)sys-con.com! 201 802-3021


SYS-CON Featured Whitepapers
ADS BY GOOGLE