What is a SOA Service - from the Business Perspective? How detailed, what level of functionality does it expose?

Clearly Defining“What is a Business Service?”
SOA Concepts
Akiva Marks
Senior SOA Architect
http:// MakingSOAwork. blogspot.com

The Great SOA Hope…

So, What’s a Service?
Defining "services" is a bit like defining “curses" -- it's hard to explain, but you know it when you hear it. Lorraine Lawson IT Business Edge Integration Blog

So, What’s a Service? #2
When to promote a service to a Business Service is very hard to tell and it depends on the company’s specific business.Aristo Togliatti Symbian Developers Journal SOA & WOA

Events Actions
Events Actions
A Service is…
Actions and Events associated with an Entity or Process
Function – I.T. ‘code’ implementing an action or event.
Entity
Process

Some Service Goals
Reusable
The next time the business needs the same functionality, it’s already there and available for use.
Single Instance
A business process has corresponding I.T. “code” that only has to be maintained and changed in one place.

Different Kinds of Services
An I.T. service is a unit of code providing an open interface that is abstracted from its implementation.
Process Services - Encapsulation of business flow and application composition. BPM workflows.
Business Logic Services - Encapsulation of functions.
Data Services – Interaction with Entities, management of data access and persistence.
Infrastructure Services - Common utility functions such as monitoring, logging, and security.

Data Services
Entity
A Service that encapsulates an Entity.
The logical view of the entity…
Database fields.
Simple Calculated fields like age.
Decoding (city code plus city name).
Simple actions upon the entity…
Insert, Update, Delete
Query (Summary, Detailed)

“Simple Customer Interaction”
Entity/Data Service
An Entity – A Data Service
- Create
- Update
- Delete
Data Functions
Customer
Service
Interface
- Everything
- Basic
- Age
Query Functions
Business Actions
- Status Change

Possible Standard Entities
Insured
Claim
Doctor
Policy

Standard Entity Actions
Insert
Update
Details
List
Publish
Retrieve

Business Logic Services
Process
A ‘simple process’ that calculates or transforms information and produces an output.
Usually a single block of code.
A function. An algorithm.

“Calculate Pension Amount”Service
A Business Logic Service – Example #1
Regular
CalculatePension
Service
Interface
Member of Parliament
Government Employee

“Calculate Salary” Service
A Business Logic Service – Example #2
(internal function)
Basic Salary
CalculateSalary
(internal function)
Salary Tax
Regular
Service
Interface
(internal function)
Health Tax
Bonus
(internal function)
Add Benefits
Determine
Vacation
Check
Sick Days

“Process Services”
Process
A BPM workflow.
A set of tasks that transforms information and produces an output. Some activities may be conditional, or alternatives, or run in parallel, it is seldom a simple chain.

“Determine Disability Eligibility” Service
A Process Service
Workflow –
Doctor Review
Determine
Eligibility
Service
Interface
Citizen
Workflow –
Medical Committee

Infrastructure Services
I.T.
Process
Services that provide I.T. functionality, such as logging, monitoring, security, printing, document processing, scanning, etc.
Often vendor provided tools or components.
“Central Logging” Service
Security Errors
Logging
Service
Interface
Application Errors
Service Errors

Composite Services
Services may relyupon other services.
Services may operateat different levels ofgranularity (detail).

BPM Workflows Use Servicesand Are Services
BPM Workflows can use services to activate and fulfill process steps.
BPM Workflows can be encapsulated by services and exposed as services.
Workflows can use other workflows as process steps.
Services can activate workflows or use workflows as part of a composite service.

Methodology: Services and Analysis
Determine High Level Entities
Determine High Level Actions
and mid-level actions against Entities
Determine High and Mid Level Business Processes
Consider whether you can compose workflows and processes with the resulting services.

Methodology: How Much To Expose?
Completely expose the Entity!
Why?
More exposed, more chance of reuse.
Less exposed, need for changes later= bad.
Changes cost a lot of money… (project, management, testing, deployment, etc.)
Hardware to handle overhead is cheap (compared to the cost of programmers and change projects).
Processing time is not significant compared to the service overhead.
Arguments why not…overhead (network, disk, CPU – now cheap), security (let the security layer handle it), extra work (one day now, many days later).
Example, Customer Entity includes Address, City Code plus City Name, Date of Birth plus Age, and all customer details available.

Methodology: How Much Functionality?
Expose the Process and it’s first level of detail.
Let calling systems manipulate the process at the level of capability the code allows manipulation.
Let the process act as a black-box engine, all switches and controls exposed for maximum flexibility.
Handle complexity with default or standard settings with overrides.
Acting as a transaction engine means the service only needs to be changed if the business process changes.
Why? Someone always needs “a little more” of what the process does exposed up until the full process options are exposed. And change costs significant money (time / effort).

Methodology: Business Services

Methodology: Business to IT Services
IT
Business

Methodology: Service Analysis
Business
IT Development
Analysis

Service Metadata
Service Overview (e.g. name, description)
Lifecycle Attributes (e.g. version, version relationships, lifecycle status)
Classification (e.g. basic, composite, infrastructure, business)
Endpoint Deployment Attributes (e.g. protocols, location, WS-* specifications)
Data Model (e.g. XML Schema, WSDL, version, semantics, validation)
Service Level Requirements and Policies (e.g. availability, capacity, responsiveness, security, transaction rate)
Mediation (e.g. routing, queuing, caching, transformation)
ServiceDependencyAttributes (e.g. services, databases, directories, frameworks)
Physical Instance Dependencies (e.g. application platform, security, management)
Business Process Model (e.g. UML diagram, business classification)
Contract information (e.g. consumers, providers, utilization)
Usage Guidelines (e.g. time of day, availability, # of users. throughput)

Thank You

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What is a SOA Service - from the Business Perspective? How detailed, what level of functionality does it expose?

by Akiva Marks on Jul 12, 2010

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What is a SOA Service - from the Business Perspective? How detailed, what level of functionality does it expose? — Presentation Transcript