Servicesbased Systems Architecture, Design and Implementation

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Services-based Systems Architecture, Design and
Implementation

• B.Ramamurthy

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Goals

• Retrospective on Project 1
• Lessons learned and pitfalls to avoid
• Discussion on plans for Project 2
• Artifacts of a large scale distributed system
• Architecting a services-based system
• Design issues in services-based system
• Anything else

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Develop/Deploy(DD) Cycle
Service Endpoint Interface
wscompile
Portable Artifacts
WSDL
Model
wsdeploy
Deployment Descriptors
Cooked WAR
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Invocation Model (client side) or Invoke Cycle
wscompile
Portable Artifacts
WSDL
Implementation -specific Artifacts
Client
Invoke web service
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Client Scenarios
Service endpoint interface
Web service 2
WSDL
Web service 1
JSP Client
Java App. Client
Servlet Client
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Artifacts the server/container

• Host with an IP (and ports)
• Web servers, servlet servers, application servers
• All can be bundled into one
• More than one can be installed in a host
  machine at different port (Project 1)
• Each has a context root, the path of which
  represents / (Ex /DBaccess.jsp)
• Each has an admin console for managing the server
  resources such a data source and message queues.
• Elegant way to access the resources in a deployed
  unit is through the container (server).
• For java, you will define JNDI (Java Naming and
  Directory Interface) names for the resources.
• Portability of deployable units (Ex Component
  technology Enterprise Java beans)

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Artifacts the data

• Relational data base object relational database
• Data modeling (Entity-Relationship modeling)
• Tables
• Operations
• Data access objects (DAO)
• Enterprise java beans (EJB)
• Enterprise information system (Amazon.com
  webservices, yahoo feeds)
• Legacy systems
• Device data (sensors)
• RSS, ATOM, XML and text feeds

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Artifacts the services

• WS creation for consumption
• Typically create a service from
  language-dependent interface/class (Ex Java
  interface class)
• Generate WSDL for publication and consumption.
• WS consumption using a published WSDL.
• Generate the language-dependent classes from WSDL
• Understand thoroughly the various components of
  the WSDL messages, port type, bindings, server
  (server, port), etc.

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Artifacts the clients

• Simple applications to rich client (ex RIA rich
  internet application)
• Internationalization (languages, monitory units,
  etc.)
• HTTP monitors, cookies and counters
• Preference profiles

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Plan for Project 2

• Commercial strength enterprise application built
  around web services offered by amazon.com ECS
• http//webservices.amazon.com/AWSECommerceService/
  AWSECommerceService.wsdl?
• Theme Federation of information from various
  sources to present an intelligent interface for
  assembling a system of components in various
  vertical domains.
• Experience is similar to ordering a computer at
  Dell site.
• Examples
• Mundane applications such as furnishing a house
  for a given budget or without a budget but with
  preferences. Based on real amazon.com data so
  that the application can be used by amazon.com
  customers.
• Building a home theater, a music system, stock
  portfolio, etc.
• Interaction models (groups rather than
  individuals)
• Add dynamism to amazon.com experience
• Make use of web services you created in Project
  2.
• Data from other sources such as yahoo feeds.
• For persistence you will have oracle data source,
  CIT data source as well as any local data.

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Plan for Project 2

• Non-functional requirements
• Reliability (fault handling, exception handling)
• Performance (caching, concurrency, thread
  pooling?)
• Elegant data access using data access objects
• Validation of any inputs
• Junit/Nunit testing
• Security authentication
• Secure access
• Asynchronous operation, push mode
• Events, notification, publish, subscribe
  operations.
• Higher level WS- standards WS-BPEL, workflow
  etc.

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Project 2 to do

• We will explore the features offered by
  amazon.com and others.
• Decide on a project, title, domain, executive
  summary and project timelines.
• Lets look at some demos.
• Links Amazon.com E-Commerce Service (ECS)
• Conceptual Model      
• ECS Usage/Query Scenarios          
• Types of data available through ECS (and not
  available)
• Sample applications (some of them are cool)