This is a presentation of a research paper on comparative study of Component based Software Engineering and Service Oriented Architecture. It covers technologies of both paradigms as well as technical discussions and justifications on SOA. It also covers modern components.

1. Component based Software Engineering v/s SOA Based Software Engineering Proposed by: Maulik Parikh Riddhi Vyas

2. Scenario A Mid tier/ Mid level company which wants to develop a product. Asked software architects for suggesting them a solution methodology. As software architects we are comparing two methodologies: Component Based Software Engineering and SOA based Software Engineering and proposing a solution to the stack holders.

3. What is CBSE? Emphasis on decomposition of the engineered systems Functional or logical components with well-defined interfaces used communication across the components Development methodology that utilizes separate software entities using: Commercially off-the-shelf products (COTS) Internally developed components Promotes software reuse Improved quality software Reduced development costs Reduces time to market for large system implementation

4. Why CBSE? Goal: Represent the system as assembly of parts(Components) The ‘buy, don’t build’ philosophy. The development of parts as reusable entities, and the maintenance and upgrading of systems by customizing and replacing such parts What is Required for that: established methodologies and tool support covering the entire component and system lifecycle including technological, organizational, marketing, legal, and other aspects

5. What is New? OOD v/s CBD

6. What is Needed? CBSE COMPONENT MODELS OMG’s CORBA Component Model (CCM) Microsoft’s COM ,DCOM ,COM+ family UML2.0 PECOS ADLs, Pin, Fractal, KobrA, SOFA

7. Basic Concepts: i)Components: Components are considered to be a higher level of abstraction than objects ii) Interface: Exported Interface Imported Interface iii)Contract: Specifies two things

8. Benefits with CBSE Reduce or Contain development costs Increasing industry competition for similar products Decreased time to market Improved software quality Demand for more complex software solutions Complex software solutions cost reduced through CBSE Increased availability of COTS components In Short: Maintainability Functionality Usability Efficiency Reliability Portability

10. No commonly accepted criteria/classification/taxonomy

12. SOA Services: Loose coupling Formal contract Abstraction Reusability Principles that service must adhered to Promote software reusability Flexibility and able to respond faster to change Self-describing and self-containing

13. SOA Architecture:

14. SOA Technologies XML: Specification to create customized markup languages Supports communication of different systems Communication is platform neutral, language neutral and self-describing syntax SOAP: Protocol specification used to exchange information via Web Services Flexible enough to use multiple transport protocols (HTTP or SMTP) Platform & language independent Relies on XML

15. SOA Technologies WSDL(Web Service Definition Language): Defines services as collections of network endpoints or ports Multiple ports define a service Clients read WSDL to determine Services available How to make SOAP calls to the service UDDI(Universal Description Discovery and Integration): Registry where businesses can list available services and discover services Composed of 3 items: White Pages - Stores contact information (address and other identifiers) Yellow Pages - Service categorizations Green Pages - Technical information regarding services

18. self-describing,

20. CBSE v/s SOA

22. Designed to be reused.

23. It must have a name, properties and an implementation.

24. Properties--- Operational constraints, its dependencies (if any) on other components, list of operation that can be reused, list of known relationships etc.

25. Service Components Interface– can be described with a programming language. Service Provider { provide output; pubReq input; spec serviceSpecification; } Interface may be described directly in the specification or indirectly discovered through reflection and introspection. Network addressable interfaces. Communicate via standard protocols and data formats.

26. Service Components Connector: It connects service components. Define the connector type and specify it by declaring its interfaces and the connection protocols. Connector Interface: It’s a set of interaction points between the connector and the service components and the connectors attached to it. Connector PubLink { publisher output; pubRequestor input; spec publishProtocol; } The connector interface“input” defines interconnection protocol between the provider and that connector.

27. Modern Components Modern components are the ones which are manufactured by a vendor using some standardized models and used by a third party who uses it as COTS-components. Modern components are accessed by vendor defined standardized architecture based interfaces. They are tightly coupled inside a container. This puts an extra processing overhead…..How??

28. Modern Components

30. Only coarse-grained objects should be exposed to the network.

31. Hard to reuse coarse-grained objects.

32. Reusable business logic should remain fine grained.

33. So Component Distribution is a problem!!!......

35. We do not want to change the interface too..

37. IS SOA a miracle cure? SOA is a step forward from component technology but not a miracle-cure. It gives loose coupling, higher reusability, faster development and a complete new style of software development. Two points of differentiation: Services are public not models of development. Can be accessed through registries as done in Yellow Pages. Services have to be largely independent from implementation specific attributes. E.g. Java, .Net or Perl. (Communication –XML and SOAP)

40. There should be a metrics to decide for a fit of service.

41. Performance with SOAP

42. SOAP is a de-facto wire protocol for web services.

43. SOAP performance is degraded due to the following:SOAP envelop extraction from SOAP packet is very time-expensive. SOAP encoding rules makes it mandatory to include typing information in all the SOAP messages sent and received.

45. SOA uses XML for data exchange and interchange.

46. A coin has two sides….

47. Higher need of data transfer  lower performance and higher usage of network and internet traffic.

48. Parsing the XML information contained in an envelop is time-consuming.

49. Very less time is consumed in serializing and de-serializing sent in a binary format over the network.

51. Future Work Component based paradigm has a long history relatively behind them. Solid methodology for developing component based applications. As SOA paradigm matures, it requires careful consideration of the role of different software artifacts in the system. e.g. clearly distinguish between reusability on different levels, for instance.

52. Conclusion SOA gives a new type of service based architecture to be used in a context free way , it does not differ significantly from existing component based frameworks like EJB. Developers can use foreign external components as Web Services. But one has to take into consideration factors like finding services, providing acceptable performance, security, transactions, maintainability in own services even to handle changeability of integrated external services or components. There are a lot of problems but there are a lot of possibilities too. In our opinion future is about Component based SOA(CSOA).

53. References Hanson, J: Coarse-grained interfaces enable service composition in SOA. URL: http://builder.com/5100-63865064520.html Siddiqui, F: Component based software engineering, a look at reusable software components (August 2003) Stal, M. : Using architectural patterns and blueprints for service-oriented architecture. Software, IEEE 23(2) (2006) 54-61 Enterprise Service Bus. URL: http://en.wikipedia.org/wiki/enterprise service bus Elrad, T., Aksit, M. , Kiczales, G., Lieberherr, K., Ossher, H. : Discussing aspects of Component Communication. ACM 44(10) (2001) 33-38

54. Q & A?