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Introduction to
Service-Orientation
    Services (Part I)
    Services (Part II)
    The Service-Orientation
Design Paradigm
    Origins and Influences of Service-Orientation (Part I)
    Origins and Influences of Service-Orientation (Part II)

Service-Orientation
Design Principles
    Standardized Service Contracts
    Service Loose Coupling
    Service Abstraction
    Service Reusability
    Service Autonomy
    Service Statelessness
    Service Discoverability
    Service Composability
    Service-Orientation and Interoperability

Effects of Service-Orientation on the Enterprise
    Service-Orientation and the Concept of "Application"
    Service-Orientation and the Concept of "Integration"
    The Service Composition

Service-Orientation
in the Real World
    Life Before
Service-Orientation (Part I)
    Life Before
Service-Orientation (Part II)
    The Need for
Service-Orientation (Part I)
    The Need for
Service-Orientation (Part II)
    Challenges Introduced by Service-Orientation (Part I)
    Challenges Introduced by Service-Orientation (Part II)
    Additional Considerations

Additional Resources
    SOA Sites
    SOA Book Series
    SOA Training & Certification
    Free SOA Principles Poster
    Notification


Service-Orientation Design Principles

Service Statelessness
Audio Podcast
The last four principles are discussed in the audio podcast Introduction to Service-Orientation Design Principles - Part 2


"Services minimize resource consumption by deferring the management of state information when necessary."

The management of excessive state information can compromise the availability of a service and undermine its scalability potential. Services are therefore ideally designed to remain stateful only when required. Applying the principle of Service Statelessness requires that measures of realistically attainable statelessness be assessed, based on the adequacy of the surrounding technology architecture to provide state management delegation and deferral options.


Figure: Incorporating a balanced and targeted measure of state management deferral can significantly enhance the scalability of individual services, an important design consideration for services that are shared across multiple compositions.

Chapter 11: Service Statelessness (State Deferral and Stateless Design) explores the options and impacts of incorporating stateless design characteristics into service architectures.





This page contains excerpts from:

SOA: Principles of Service Design
by Thomas Erl

ISBN: 0132344823, Prentice Hall/PearsonPTR, Hardcover
240+ Full Color Illustrations, 573 pages

Download the free Color SOA Principles Poster at www.soaposters.com.
For more information about this book, visit
www.soabooks.com.
The Prentice Hall Service-Oriented Computing Series from Thomas Erl
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