Contemporary SOA, Part I

1
Contemporary SOA, Part I

• 605.702 Service Oriented ArchitectureJohns-Hopkin
  s University
• Montgomery County Center, Spring 2008
• Session 3 February 13, 2008
• Instructor T. Pole

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Session 3 Agenda

• Required Reading for This Week
• Chap 5, sections 5.22, 5.3 5.4
• Chap 6 Web Services and Contemporary SOA, part I
• Todays Presentation
• Todays Lecture
• In Class Case Study Sharing the Load (STL)
• Assignments
• Review Ex 1
• Assign Ex 2

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Lecture from Text

• Chapter 5 continued
• 5.3 WSDL
• 5.4 SOAP Messaging
• Chapter 6 Contemporary SOA Part I
• 6.1 Message Exchange Patterns
• 6.2 Service Activity
• 6.3 Coordination
• 6.4 Atomic Transactions
• 6.5 Business Activities

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5.2.2 Service Models

• Models of services different models that
  services can assume
• Business Service Model
• Automates, implements or represents business
  tasks or entities
• Utility Service Model
• Not a business service or controller service
• Controller Service Model
• Controls other services to perform a greater task

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5.3 Service Descriptions with WSDL

• Required by Ultimate Receivers
• Which are always service providers
• Service endpoints
• Provides formal definition of the interface
• Also defines the physical location of the service
• WSDL Definition
• Abstract and description components
• Metadata and service contracts
• WSDL, XSD and policies
• Semantic Descriptions
• Advertising and discovery

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5.4 Messaging with SOAP

• Soap Message Envelope contains the header and
  the body
• Intelligent and self-sufficient
• Header Blocks
• Additional custom instruction on how to process
  SOAP messages, basis of WS- extensions
• Message Styles RPC and Document styles
• Message Paths - route taken by path

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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 (infomration 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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Review Exercise 1

• Build an ASP .Net Web Service (service provider)
• Build a client (proper name is service consumer)
  to your service
• Setting up IIS Web and SOAP Server
• IIS and ASP.Net setup tips
• Requirements for Exercise 1

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Review Exercise 1 Build an ASP.Net Web
Service 1 of 2

• Start VS 2005
• File -gt New -gt Web Site
• Choose ASP .Net Web Service template
• Type in a new path for the web service on your
  local machine
• Location HTTP
• http//localhost/whatever name you like
• Language Select C
• Click OK
• Click Solution Explorer tab (left side of screen)

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Review Exercise 1Build an ASP.Net Web Service
2 of 2

• Select in explorer window
• http//localhost/whatever
• App Code
• Service.cs
• Locate the web service that implements
  HelloWorld()
• Change the text output string to something
  interesting
• Select from menu Build -gt Rebuild Solution
• At bottom of screen notice the build log entries
• Should see Build 1 succeeded .
• Run in debug mode Menu Debug -gt Start Debugging
• Add a new web.config file option, say yes
• Click on HelloWorld link
• Click on Invoke button

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Review Exercise 1Build a Client 1 of 2

• Another new project File -gt New -gt Project -gt C
  Projects folder -gt Windows Application
• Pick a good project name
• Select in explorer windows, left of screen,
  Client_name\References with mouse right add web
  reference
• Browse to Web Services in this solution
• Select the Web Service you build
• Add something to the Web reference name field
• Click add reference
• Explorer browse to Client_name\

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Review Exercise 1 Build a Client 2 of 2

• Add a button and a textbox to Form1 by drag and
  dropping them from the Toolbox palette
• Click on the textbox and change its name to
  something meaningful
• Double click on the button opens the code to
  the event handler on the button
• Enter the code
• localhost_4b.Service Service new
  localhost_4b.Service()
• string Response
• Response Service.HelloWorld()
• ResponseTB.Text Response
• In solution explorer click right on client
  project and click Set as start up project
• Menu Build -gt Rebuild Solution
• Menu Debug -gt Start Debugging

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Review Exercise 1 Setting Up Windows XP IIS
Server

• IIS is an optional install on Windows XP Pro
• Control Panel-gtAdd/Remove programs-gtAdd/Remove
  Windows Components-gtSelect Internet Information
  Services (IIS)-gtNext, Finish
• Select the Front Page 2000 Extensions option
• http//localhost

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Review Exercise 1 IIS and ASP.Net Setup Tips

• I've installed the .NET Framework, but ASP.NET
  doesn't seem to work. What can I do to fix it?
• You must have IIS (Internet Information Services)
  installed before you install the .NET Framework.
• If you install IIS after you install the .NET
  Framework, you must also register the ASP.NET
  extensions with IIS.
• You can do this by running the aspnet_regiis
  executable from
• windows root directory\Microsoft.NET\Framework\
  version of the .NET Framework\aspnet_regiis -r
• where windows root directory is the directory
  Windows is installed to (typically c\windows or
  c\winnt)
• and version of the .NET Framework is the
  version of the .NET Framework you have installed.
  
• The directory for .NET 1.0 is v1.0.3705, for 1.1
  is v1.1.4322, and for 2.0 is v2.0.50727

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Review Exercise 1Requirements Your First .Net
SOAP Based Web Service

• Create a Web Site with a Web Service using C and
  VS 2005
• The Web Site will be names WS_01_your two
  initialsnumber 1..9
• Your initials, first and last name
• Number 1 through 9 in case you share the same
  initials with another student in class
• The operation will be named My_creators_name_is
• It will return a string with your name in it.
• Create a desktop C client to invoke the web
  service, and display its results
• Submit the complete folder contents that contain
  your projects
• Select the Solution (top item) in solution
  explorer
• Go to menu Project -gt Properties
• Will display the location of all your (two)
  projects files location.
• Copy them to a common root folder if they dont
  already have one, and sip the folder, email it to
  me prof_at_Hisdomain.net

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Exercise 2 Requirements

• Create a Web Site with a Web Service using C and
  VS 2005
• The Web Site will be names WS_02_your two
  initialsnumber 1..9
• Your initials, first and last name
• Number 1 through 9 in case you share the same
  initials with another student in class (lets
  check this NOW)
• The operation will be named CombineParameters
• It will take two inputs (parameters) and return a
  value
• Inputs a string named Sentence and an integer
  named Number
• Returns a string You sent the number insert
  Number here and the sentence insert Sentence
  here.
• Create a desktop C client to invoke the web
  services operation, and display its results
• Submit the complete folder contents that contain
  your projects
• Select the Solution (top item) in solution
  explorer
• Go to menu Project -gt Properties
• Will display the location of all your (two)
  projects files location.
• Copy them to a common root folder if they dont
  already have one, and zip the folder, and email
  it to me prof_at_Hisdomain.net
• Also print out the two C files, one from each
  project,and hand them in

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Exercise 2 GUI Creation Tips

• Use the property window
• Use the Button, Label, and TextBox UI widgets
• Name property, names the variable that lets you
  access UI widgets from code
• Multiline, true or false says whether multiple
  lines of wrapping text can be used in TextBox
• Text property, is value in the TextBox
• Double click the button to create and edit event
  handler for that button
• Converting string to integer
• int System.Convert.ToInt16( string )

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Exercise 2 Sample Code Service

• WebMethod
• public string CombineParameters(string Sentence,
  int Number)
• string ReturnValue
• ReturnValue "You sent the number "
• Number.ToString()
• " and the sentence "
• Sentence
• ."
• // note single quotes used as double quotes
• return ReturnValue

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Exercise 2 Sample Code Consumer

• private void button1_Click(object sender,
  EventArgs e)
• localhost.Service Service new
  Ex2_S08_Service1_Consumer
  .localhost.Service()
• string ReturnValue ""
• string Sentence SentenceTB.Text
• int Number Convert.ToInt16(
  NumberTB.Text )
• ReturnValue
• Service.CombineParameters(Sentence
  , Number)
• ResultsTB.Text ReturnValue