Contemporary SOA, Part II

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Contemporary SOA, Part II

• 605.702 Service Oriented ArchitectureJohns-Hopkin
  s University
• Montgomery County Center, Spring 2008
• Session 4 February 20, 2008
• Instructor T. Pole

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Session 4 Agenda

• Required Reading for This Week
• Complete Chap 6
• Chapter 7 Contemporary SOA part II
• Sections 7.1 through 7.
• Todays Presentation
• Todays Lecture
• In Class Case Study
• Introduction of Federated System Engineering
  Asset Management System F-SEAM
• This will lead us into the class project
• Assignments
• Review Ex 1 and Ex 2
• Resubmit incomplete/non-functioning exercises by
  02-27-08

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Change in Schedule

• I will be out on March 5, 2008
• Therefore I have moved the mid term up one week
  to the 5th
• It will cover less material then originally
  planned
• March 12 will be a lecture instead of a mid term

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Lecture

• Chapter 6 Contemporary SOA Part I
• Coordination
• Atomic Transactions
• Business Activities
• Orchestration
• Choreography
• Chapter 7 Contemporary SOA Part II
• Addressing
• Reliable Messaging
• Correlation
• Policies
• Metadata Exchange
• Security
• Notification and Eventing

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Ch 6 Transactions, Business Activities,
Orchestration and Choreography

• Review of 6.1 6.4
• Business Activities Long running multi-step
  tasks, among multiple services
• Orchestration Centrally controlled workflow
  among services
• Choreography Like an orchestration, but without
  central control or ownership

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6.1 Message Exchange Patterns (MEPs)

• How services can share and cooperate in
  processing messages
• Primitive MEPs
• Request response
• Fire and forget
• Single destination, multi-cast or broadcast
• Complex MEPs
• Based on Primitive MEPs
• Example Publish and subscribe
• WSDL MEPs
• Request-response, solicit-response, one-way,
  notification

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6.2 Service Activity

• Interaction of group of services to complete a
  task
• Sort of a MEP plus the pattern of messages
  exchanged to perform a specific task
• One MEP can perform multiple tasks
• Primitive activity Simple MEP
• Complex Activity Multiple MEPs or a large
  complex MEP

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6.3 Coordination

• Coordination establishes a framework for complex
  activities to be managed and distributed to
  activity participants
• Can be extended to the concepts of choreography
  and orchestration
• Usually requires context state (information about
  the state of the complex activity) to be
  retained

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6.4 Atomic Transaction

• WAKE UP this section is complicated, boring and
  important
• ACID
• Atomic - All or nothing, you cant do part of a
  transaction
• Consistent system data models must remain so
• Isolated transactions cant interfere with each
  other
• Durable Changes made by a transaction can
  survive subsequent system failures

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6.5-6.7 Business Activities Orchestration and
Choreography

• 6.5.2 Business Activity Coordinator
• If business tasks and entities can be represented
  by services, then coordinator service(s) can be
  used to develop business agility through
  tailorable service base applications
• Centrally controlled Orchestration
• Peer to peer coordinated choreography

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Ch 7 Web Services and Contemporary SOA Part II

• 7.1 Addressing Multi-stop and alternate
  addressing
• 7.2 Reliable Messaging Assurance of delivery
  and order of delivery
• 7.3 Correlation multiple ws- implement it, to
  preserve state across multiple message exchanges
• 7.4 Policies adds metadata which attach
  properties to web services, used to implement
  other ws- extensions
• 7.5 Metadata Exchange ability to issue message
  request to retrieve metadata for service
  providers give me all the data I need to evalute
  and interact with your service

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SOA Terminology

• Service roles
• Not a client but a service requestor or consumer
• Not a server, but a service provider
• An intermediary service transitions from a
  service provider to a requestor
• Passive and active intermediaries
• Initial sender and ultimate receiver

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SOA Case Study System Engineering Asset
Management Systems

• Based on Document and Content Management (CM)
  concepts
• Reference
• www.aiim.org
• www.asist.org
• Content Management
• IT system which manages not just documents
  (files) but content (information explicit and
  implicit in the files)
• Asset Management
• Using CM, data warehousing, and knowledge
  management (KM) techniques to manage intellectual
  property
• Intellectual Property what an individual or
  organization knows, specialized knowledge based
  on skills, training, and experience

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System/Software Engineering Assets

• SE Assets are all of the work products consumed
  or produced during the development life cycle of
  systems
• SE Assets include the documentation of, source
  code for, design artifacts of a system/software
  engineering organization
• These assets capture the intellectual property of
  system/software development organizations

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System Engineering Asset Management

• The management of the capture, organization,
  preservation, access, and use of engineering
  assets
• Based on CM, KM, Software Reuse, Software
  Framework techniques
• Every software engineer should be familiar with
  this topic
• Every IT architect should be very familiar with
  this topic
• A UDDI directory is one part of a complete SEAM
  system
• Reference
• www.iasahome.org
• Flashline (BEA ??)
• LogicLibrary

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CM, DM, KM Concepts

• Repository
• Either a very basic asset management system (AMS)
  or the part of an AMS which actually stores
  content and metadata
• Content versus Document (or File)
• The document (e.g. file) is a container of the
  actual information the document contains
• Different renditions (powerpoint, word doc, etc)
  can each be a different presentation of the same
  content
• Metadata
• Data which describes data. e.g. an abstract or
  summary
• Query
• A defined search against a repository

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Basic Services of a SEAM System (SEAMS)

• Submit New Asset
• To a repository (e.x. a rudimentary SEAMS)
• Update Existing Asset and/or Metadata
• Query for Assets
• Retrieve Asset(s)
• Synchronize Asset Metadata

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Basic Components of a SEAMS

• Repository component physical storage of data
  and metadata
• Ingest component collects the data and
  metadata, may also derive additional metadata,
  validates and organizes
• Access component supports search and retrieval
  from repository
• Other components are required and will be covered
  later

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Class Project A Federated SEAMS

• A federated system is a system of systems
• E.g. The U.S. Federal government is a government
  that unites, (not replaces) the individual state
  governments
• Some services are reserved for the states, some
  for the federal government, some are shared.
• In a Federated SEAMS, multiple engineering asset
  management repositories share services in a
  cooperative, loosely coupled distributed
  architecture.
• Sound familiar?
• Loosely coupled
• Distributed
• Cooperative
• Sharing services

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Basic SEAMS Services

• Ingest Service
• Ingest New Asset Operation
• Update Asset Operation
• Update Asset Metadata Operation
• Access Service
• Query Operation
• Retrieve Operation

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STL Architecture
SEAM Client Service Consumer
Ingest Ingest New Asset Update Asset Update
Asset Metadata
Access Query Retrieve
SEAM Repository
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Exercises and Assignments

• Review Exercise 1 first service
• Review Exercise 2 Passing parameters
• Check Schedule page on web site for assignment
  updates
• Assignments 1 and 2 have been rescheduled at
  least one week later in semester