2005 adobe systems incorporated. all rights reserved. duane nickull adobe ® an introduction to the...

2005 Adobe Systems Incorporated. All Rights Reserved.

Duane Nickull

Adobe®

An Introduction to the OASIS Reference

Model for Service Oriented Architecture

(SOA)

[email protected]

2005 Adobe Systems Incorporated. All Rights Reserved. 2

When people talk about SOA…

Would be nice if we had consensus on what SOA is.

Thoughts: SOA is an architectural paradigm (model).

So how do we express it as architecture? Is it sufficiently different from other types

of architecture? If SOA is “X”, what is not SOA?

SOA does not specifically mean Web Services although WS is a popular implementation of SOA.


Defining SOA…

Should not do it by referencing an implementation.

If SOA is Architecture, as the name implies, it should be definable as architecture.

A Reference Model is a good mechanism to define SOA. Why? (next slide).


The Reference Model for SOA…

Is not intended to be architecture for a single SOA system.

Is an ABSTRACT model for a range of Service Oriented architectures and analysis / comparison thereof.

Is a framework for understanding significant relationships among the entities in a SOA environment.

Is based on a small number of unifying concepts of all SOA’s.


How does a RM relate to other stuff?

SOA Framework


So what is SOA exactly?

A paradigm for organizing and using distributed capabilities that may be under the control of different ownership domains.

A framework for matching needs and capabilities.

A view of architecture focusing on “Services” as a mechanism to allows interactions between those with needs and capabilities.


OASIS SOA Reference Model

DRAFT – may change


Core Concepts of SOA (DRAFT)

Service: A mechanism by which needs and capabilities are brought together.

Service Description: Artifact declaring all relevant aspects of a service required to interact with the service.

Capability: an ability to perform a specific set of functions resulting in a real world effect.

Visability: The capacity for those with needs and those with capabilities to see each other and interact.



Execution Context: Set of technical/business elements that form path between those with needs and capabilities. Permits information to be exchanged, actions to be performed and provides a decision point for any policies and contracts that may be in force.

Policy: A set/range of constraints imposed on any entity when invoking a service. If ignored, the invocation request may be denied.



Exchange: The act whereby two or more entities come together within the context of a single interaction.

Real World Effect: The result of an interaction with a service.

Interchange: the activity of using the capability. An “act” rather than an “object”


Recurring Q&A…

Why are concrete things not in the reference model (security, messaging protocols etc…)?

Why don’t I see two entities in the RM (service consumer and service provider)?

How does “infrastructure” fit into the reference model?

Does the SOA reference model require definition of core infrastructure?

Why is SOA not BPM centric? (see next slide)


Service

Capabilities

Service Consumers

Where do things live?

Core SOA

Business Process, State alignment, orchestration, choreography, etc..

Applications, ECM, DB, …

In a layer diagram, layer “n” is only visible to layers (n +1) and (n – 1)

Visible

Notvisible

What services are used for

Sources, functionality for capabilities


BPM is a layer over SOA.

Data

Data ServerServerServer

Server

Service

Service

Service

ServiceService

Server

Server

Courtesy Booz Allen Hamilton – http://www.bah.com

Business & Application

Tier

ServiceOriented

Tier

Business Process

Acquisition

Business Process

Human Resources

Business Process

Grants Management

Business Process

Customer Service

Business Process

Budgeting and Forecasting

Process & Orchestration

Tier

Service


Processes can also be under services

Processes aggregate multiple services and can themselves be exposed as services.

Since services hide the resources behind them, not all details of the process may be available.

Service Process

* 1

-<<represented as>>* *

<<uses>>


About Reference Models


Reference Model

A reference model is an abstract framework for understanding significant relationships among the entities of some environment, and for the development of consistent standards or specifications supporting that environment.

A reference model is based on a small number of unifying concepts and may be used as a basis for education and explaining standards to a non-specialist.

A reference model is not directly tied to any standards, technologies or other concrete implementation details, but it does seek to provide a common semantics that can be used unambiguously across and between different implementations.


Where would the housing industry be?

Implied reference model means architects know their blueprints will be understood and that manufacturer’s are ready to supply the parts needed.

“Palette” of items to work from in model: Doors, Windows, frames, Gyproc, Flooring, Plumbing etc.

Vendors are aligned with architects views. Entire industry wins!


Reference Models are Abstract

The RM for “house” is not specific enough for a contractor to build a house.

The RM aides the architect to make a specialized architecture for a specific set of requirements, using elements of the RM.

Most industries have an implied or explicit reference model: Automobile, Aerospace, Logistics, Bicycle,

Skis, etc.


OASIS SOA RM TC

(optional slides)


OASIS SOA Reference Model TC

Chartered February 2005 Problem to be solved:

"Service Oriented Architecture" (SOA) as a term is being used in an increasing number of contexts and specific technology implementations, sometimes with differing or conflicting understandings of implicit terminology and components.

The proposal to establish a Reference Model is intended to encourage the continued growth of specific and different SOA implementations whilst preserving a common layer that can be shared and understood between those or future implementations.


OASIS SOA Reference Model TC

Purpose: The SOA-RM TC will deliver a Service Oriented Architecture Reference Model (SOA-RM).

The TC may also create sub-committees, promotional material, liaisons or other promulgation of the TC's work, in order to promote the use of the SOA Reference Model.

May help vertical industries develop SOA for their requirements.


To develop a Reference Model for SOA

The TC is asking itself these questions: What elements are common in all

implementations of SOA? ( be careful – think about this)

(Paraphrased) What are the core things that make SOA service oriented?

How do we describe those as abstract concepts? What relationships exist amongst those

concepts? How do we represent those concepts without

referencing concrete implementations.


Existing situation in Web Services

WSDL XML &SchemaSOAP

Base Standards

WS-RMWS

Addressing Reg/RepUDDI

WS-SecurityWS-Trust

WS-*

RequirementsQuestion: How do I account formy requirements and organize components when building a concrete architecture?


Thoughts on developing specific SOA’s

Probably not logical to try and develop a “one size, fits all” architecture for SOA or WS.

Not rational to develop multiple architectures in standards bodies for every set of requirements.

Best solution: develop an SOA reference Model. Used by architects to guide development of specific

service oriented architectures. Model for a “way of thinking” when architecting. Re-useable by multiple architects writing SOA for

multiple domains. Helps architects slot existing standards into their

architectures.


SOA RM used for range of WS architectures

WSDL XML &SchemaSOAP

Base Standards

WS-RMWS

Addressing Reg/RepUDDI

WS-SecurityWS-Trust

WS-*

Requirements

Guides developments of

SOA-RM

SpecificArchitectures

Uses

Input for


References

OASIS SOA RM TC - http://www.oasis-open.org/committees/tc_home.php?wg_abbrev=soa-rm

Thank you – Duane Nickull, [email protected]

2005 adobe systems incorporated. all rights reserved. duane nickull adobe ® an introduction to the...

Documents

soa framework slide

soa environment

adobe systems incorporated

popular implementation

single soa system

object slide

service description

duane nickull adobe