SOA Architecture



What is Middleware?
nA software that helps disparate and distributed applications to collaborate with each other
nHelps leverage the best-of-breed products
nCompanies can get more ROI by being able to reuse
nSOA is the hottest middleware strategy till date.  Examples:

qBPEL, OSB

 What is SOA?
“Next big thing ??”, you would wonder, “Can you tell me more?  What is SOA all about?”

 What is Service-Orientated Architecture?
nNot a technology or product, more a design approach
n
nSOA is an architectural style which helps in building connected enterprise applications to provide solutions to business problems. By following SOA, enterprise applications modules can be exposed as web services which helps in easy integration and can be reused.
n
n“Services” are
qAtomic, do not depend on other services run beforehand
qTechnology and implementation neutral - J2EE, .NET, PL/SQL
qPublished in directories so that they can be discovered and reused !
q
nAs an architectural style, SOA promotes loose coupling, interoperability assembling of applications from existing processes
nFrom customer's perspective it's about integrating different systems to helps IT deliver solutions that are flexible à Can adapt to changing markets, increasing competitive pressures and evolving customer needs
n
nServices can exchange data using a common platform (OSB) or can be orchestrated using declarative language (BPEL)
n
Architecture for Oracle Fusion Applications

What’s the Big Deal?
“Okay.  SOA proposes an application design consisting of weaving together of multiple services”, you would say, “But what’s so great about this S-O-A?”

Why SOA Makes Sense:
Technical Benefits

nBuilding business processes is faster and cheaper:
qExisting services can more easily be reused
qApps can expose their services in a standard way
nApplications can be exposed more easily to diverse clients:
qWindows clients, ASP.NET/JSP, PL/SQL, Java etc.

nApplications can adapt to change

Why SOA Makes Sense:
Business Benefits

nBusiness people understand services
qSo IT people can talk with them more easily
nApplications or business processes might be more easily outsourced
qBecause they’re well-defined and discrete
nSolutions are cheaper to build
qReuse = Reduce cost

qLoose coupling = Less impact for any change = Less time to spend changing code due to requirement change

 Proof ?
n“Well, this definitely sounds good … but can you show where SOA has been applied in real world ?”

 SOA Application Examples in the real world
nData/Apps Integration
qFile to DB (Inbound Interface)
qInformation syncing from Oracle EBS to Siebel, PeopleSoft to JDEdwards
nProcess Portal
qParallel data processing
qContent publishing
nWorkflow
qDocument Approval
qLeave Application
nModern Web Applications
qInternet Banking
qContract Management
qNew Employee Hire
nBusiness Process Management
qP2P, O2C

qMedicare Eligibility Determination and Enrollment 

 SOA Application Examples in the real world – Inbound Interface Design
nI want to transfer data from legacy system that produces csv output to a database.
nUse a file adapter to easily read a file.  You can also specify the frequency to poll for the file, file name pattern, archive the file after reading and so on.
nWe can validate the data before inserting – verify all the fields conform to a xml schema
nWe can enrich the data before inserting.

nWe can perform routing to different locations - write rules to decide whether to insert the data or not, or to insert in some other DB or create another file

 SOA Application Examples in the real world – Information syncing
nI capture item information in an Item Management System.  However, once the item is entered, this information needs to go to Oracle EBS.  Another division wants this information delivered to them in their FTP site
nUse Adapter to listen to Item Management System’s Item table. Whenever a record is entered, the SOA application is started and this data is sent to the specified location.  If tomorrow, I want to send it to one more system, I can do it with minimal effort

 SOA Application Examples in the real world - Parallel Data Retrieval
nI want to invite bids for RFQ sent to suppliers.  Can I send the RFQ to multiple suppliers in parallel, and then wait for each of the responses

 nUse parallel processing capabilities of BPEL.  BPEL provides a construct called FlowN using which you can spawn as many parallel flows as required, on the fly!

SOA Application Examples in the real world – Document Approval
nOnce a PO is created, it needs to be approved
nApproval depends upon PO Amount.  If amount is greater than USD10,000, it needs 3 levels of approval else only 2 levels
nThe approvers must be managers of the person submitting.
nIf the approval is not obtained in 2 days, the issue should be escalated to next manager
nAny document that contains a line item belonging to IT category must be sent as an FYI to the IT department

nIt should be possible to utilize different voting schemes – first approver wins, majority or consensus 

 nUse BPEL to orchestrate human task, business rules to achieve this. 

 SOA Application Examples in the real world - New Employee Hire
nFor a new joinee, we need to
nRaise request in access provisioning system for email, VPN etc
nSend filled PDF form for AMEX card
nUpdate HR tables

nSend email to Sodexho team

nUse BPEL to bind these different system and come up with an application.  Identify things that can be done in parallel.

 SOA Application Examples in the real world – Order to Cash
nI want to develop O2C cycle.  We have following requirements to be met
qOrders come from a web portal
qOrder data is stored in Oracle EBS
qCustomer credit rating information comes from bank
qCustomer Data accessible using an EJB
qPO Approval can be manual or automated.
qRFQ needs to be sent to various shipping companies and lowest quote should be selected

qCustomer must be sent an email and SMS upon Order fulfillment


nUse BPEL to bind these different system and come up with an end-to-end system.  

 Market Value
nMarket value is directly proportional to the number of potential applications
nMarket value is inversely proportional to number of professionals
nIn current times, its only your knowledge of new things that can sail you through
nPaucity of quality training
nWhich is good!  Because it means less competition
nIntegration solutions
nVendor specific – TIBCO, JCAPS
nOpen standard – Oracle SOA

nWith Oracle emerging as the leader in Apps, Oracle SOA has a secure future
“hmm…sounds interesting.. 

So, what do I need to know technically?”


 Pre-requisites
nTechnology wise
qBasic understanding of XML, XSL, XSD
qCore Java knowledge a plus
q
nExcellent career option for
qPeople familiar with Oracle Apps, Peoplesoft, Siebel
qJava, .NET developers
qWeb developers

qSun JCaps, TIBCO, EAI

 Communication among systems
Communication among consumers and providers or services typically happens in heterogeneous environments, with little or no knowledge about the provider.
Services exchange information through messages.
nWhen communication happens, the message coming from one system can be different from the message expected by the other system.  We need a way to convert or transform the message from one to the other  
nMessages can be received through any protocol such as HTTP(s), JMS, File , and may require to be sent using same or different protocol.  So we need a way to transform from one protocol to the other
nWe may require the same message to be sent or routed to multiple targets.

nIn comes “Service Bus” – it can do routing, message transformation, protocol transformation and more

OSB
OSB analogy

 Orchestration of Services
nOrchestration of services is required when there is a requirement to combine existing services into new services.
nSolution should allow assembling a set of discrete services into an end-to-end process relatively easily (development-wise and conceptually).

nThere is a solution - BPEL

 Business Process Execution Language BPEL
nBPEL:
qIs a technology to create a program that can invoke web services
qIt presents a very intuitive flow-chart type representation that can be easily understood and modified
nMore technically, it is a markup language for composing a set of discrete services into an end-to-end process flow
qBPEL Process is a web service, hence has a WSDL document that describes its operation

qinvokes operations described in interfaces in the WSDL of other services.
BPEL Example – Internet Banking
Can services be created for EVERY conceivable system in this world

Yes

How do I create a service out of a database ?

Use “Adapters”

Some of the Adapters Available for 
Oracle SOA Suite…

Oracle SOA Suite
nProvides “components” for designing, deploying, and managing “composite applications”.
q“Composites” enable you to easily assemble multiple technology components into one SOA composite application
q“Components”
nBPEL
nOSB
nMediator
nHuman Workflow
nBusiness rules
nAdapters (FTP, DB, AQ, JMS, MQ, Apps, Siebel, PSFT…)
nBAM, ODI

 Thank you




































































































































Web Services Concepts

Web Services Concepts


Objectives

nAfter completing this lesson, you should be able to do the following:
qUnderstand power of web services
qUnderstand WSDL
qUnderstand SOAP

Introducing Web Services


nWeb services are:
qSelf-describing business functions
qAccessible from any Web-connected device using:
nMessaging Protocols – The messaging protocols are standards-based and are platform independent.  These enable one service to call another one  - SOAP over HTTP, JMS
nProgramming standards – The underlying programming standards help create services that conform to a predefined structure.  This means it is possible to figure out what the service does in a platform and language independent way. - WSDL
nNetwork registration – The services can be searched in a common way - UDDI

Web Services Communication Flow

Web Services Communication Flow Example

nTo understand how web services work, lets take an example.
n
nScenario – A Citibank customer wants to pay his Vodafone phone bill through the bank’s website. 
n
nSolution
1.First, the Vodafone IT team would create a service that allows one to pay their bills through a web service.  This service may be implemented in any way they please, using ADF, POJO, PL/SQL etc.  However, the service needs to expose its interface according to WSDL specification
2.In order to facilitate clients to be able to find this service, the Vodafone team publishes this WSDL to a web services directory.  The directory is capable of storing different kind of information like the request and response messages, version, publisher details, type of service etc.  All this information is structured in a standard way so that interested parties can search or discover them.  This common format is the UDDI
3.Citibank IT team, which is developing their website, and want to provide this service to their customer, finds the service developed by Vodafone team.  This completes the setup.
4.When a customer chooses to pay his bill, the required information is sent to the Vodafone Bill Payment web service.  This communication is done using a SOAP message.  As SOAP can work over HTTP, which is the most used protocol on the Internet, this invocation can utilize the power of Internet
5.The Vodafone Bill Payment service acknowledges success or failure of the transaction
●
nThe above example brings out the interplay of:
nMessaging protocols - SOAP
nProgramming standards – Interface based on WSDL standard
nNetwork registration – Information stored as per UDDI standard
n
nNote: A Public Registry, while a really cool concept, didn’t really take off as expected.  However, the concept itself found takers at organization level and typically an organization that takes its SOA seriously will have a registry setup.

 
Describing a web service

Lets understand what it takes to describe a web service.  If we can appreciate these, then understanding why WSDL looks like it does would be that much simpler.
•Requirement 1: We need to tell what is the location of this web service
•Requirement 2: We need to tell what is the language  the web service speaks
•Requirement 3: We need to tell what functions or operations this web service is providing
•Requirement 4: We need to tell what input and output parameters the service takes
•Requirement 5: We need to tell the datatype of these parameters

WSDL Enters….

nA WSDL document is just a simple XML document.
nIt contains set of definitions to describe a web service.
nWSDL document fulfills all the above requirements
qRequirement 1 – Where is the service hosted
n<service>
qRequirement 2 – What protocol to use to talk to the service
n<binding>
qRequirement 3 – What are the operations
n<portType>
qRequirement 4 – What are the parameters
n<message>
qRequirement 5 – What is the datatype of the messages
n<type>

Introducing WSDL

nWSDL stands for Web Services Description Language
nWSDL is written in XML
nWSDL is used to describe Web services
nWSDL is also used to locate Web services
WSDL is a W3C recommendation

WSDL Document Structure


WSDL Ports

nThe <portType> element is the most important WSDL element.
nIt describes a web service, the operations that can be performed, and the messages that are involved.
nThe <portType> element can be compared to a function library (or a module, or a class) in a traditional programming language


Operation Types


One-way operation type


The operation can receive a message but will not return a response


Request-response operation type

The operation can receive a request and will return a response


nNow, a web service operation can take only one parameter.  But I want to pass multiple parameters……what do I need to do 

WSDL Messages

nThe <message> element defines the data elements of an operation.
nEach message can consist of one or more parts. The parts can be compared to the parameters of a function call in a traditional programming language. 

nI want to pass a complex object to my web service……what do I need to do 

WSDL Types

nThe <types> element defines the data type that are used by the web service.
nFor maximum platform neutrality, WSDL uses XML Schema syntax to define data types.


nI want my web service to be accessible to a HTTP client, as well as to a RMI client and a SOAP client……what do I need to do 

WSDL Bindings

nThe <binding> element defines the message format and protocol details for each port.



nbinding
qname – can be anything
qType – points to port
nsoap:binding
qStyle – rpc or document
qTransport – soap protocol to use
noperation
qDefines each operation the the service exposes

WSDL Bindings

nThe <binding> element provides specific details on how a portType operation will actually be transmitted over the wire.
nThe bindings can be made available via multiple transports, including HTTP GET, HTTP POST, or SOAP.
nThe bindings provide concrete information on what protocol is being used to transfer portType operations.
nFor SOAP protocol, the binding is <soap:binding>, and the transport is SOAP messages on top of HTTP protocol.
qWSDL 1.1 includes built-in extensions for SOAP 1.1. This enables you to specify SOAPspecific details, including SOAP headers, SOAP encoding styles, and the SOAPAction HTTP header. The SOAP extension elements include:
nsoap:binding
nsoap:operation
nsoap:body
nYou can specify multiple bindings for a single portType.

WSDL Services

nThe <services> element connects the binding to an actual URL where the service is available.


A service element describes a Web service as a collection of port elements. A port element defines a specific network address for a binding. The sample below shows the basic outline of a service that supplies an address for a SOAP binding:
<service name="ServiceName">
   <port name="PortName" binding="BindingRef">
      <soap:address location="URL"/>
   </port>
</service>
The ServiceName sets the name of the service. The PortName sets the name of the specific address. The BindingRef refers to the name of a binding element. The BindingRef must be namespace qualified if the targetNamespace for the WSDL definitions element is not the same as the default namespace.

Complete WSDL Example


SOAP

nSOAP stands for Simple Object Access Protocol
nSOAP is a communication protocol
nSOAP is for communication between applications
nSOAP is a format for sending messages
nSOAP communicates via Internet
nSOAP is platform independent
nSOAP is language independent
nSOAP is based on XML
nRelies on other Application Layer protocols (most notably Remote Procedure Call (RPC) and HTTP) for message negotiation and transmission.
nSOAP is a W3C recommendation

SOAP Message Structure


SOAP Request 


SOAP Response


UDDI

nUDDI stands for Universal Description, Discovery and Integration.
nThe UDDI specification enables businesses to quickly, easily, and dynamically find and transact with one another.
nUDDI enables a business to
1.Describe its business and its services,
2.Discover other businesses that offer desired services
3.Integrate with these other businesses. 

UDDI Data Model

The information that makes up a UDDI registry consists of instances of four core data structure types, the businessEntity, the businessService, the bindingTemplate and the tModel, together with instances of additional data structure types defined in the UDDI API Schema.
Each of the core data structure types is used to express specific types of data, arranged in the relationship shown 


Why do we need a registry

nThe ability to register, discover, and govern Web services is an essential requirement for any Service Oriented Architecture (SOA) implementation.
nA highly available environment contains multiple application server nodes, multiple instances, and multiple processes. Regardless of where the services will be deployed they have to be flexible enough to run anywhere without requiring changes to the actual process implementation.
nThis need may not be fully appreciated in the early stages of an SOA roll-out when dealing with a small number of services.
nHowever, large organizations will typically need to support a large number of Web services, and as the number of services deployed grows to dozens or hundreds, centralized facilities for access and control of service metadata and artifacts becomes critical.
A service registry provides these capabilities and is a key infrastructural component and cornerstone for SOA deployments

Registry and UDDI

UDDI defines a framework to enable the establishment of service registries to provide distributed directory service to the producers and consumers of Web services. It includes a common set of SOAP-based APIs to support registration and advertisement of Web services by service producers, and to facilitate the searching and lookup of Web services by service consumers.

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Howdy! My name is Suersh Rohan and I am the developer and maintainer of this blog. It mainly consists of my thoughts and opinions on the technologies I learn,use and develop with.
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