XML%20%20A%20Middleware%20Mechanism?

1
XML A Middleware Mechanism?

• Contents
• Middleware - CORBA
• Interoperabilty Requirements
• What Does Middleware Provide?
• XML for Component Integration
• Advantages and Disadvantages
• Synergies

2
What is Middleware?

• Glue for Components
• Sits Between OS and Applications
• Distributed Object Services
• CORBA, COM, DCE, Java/RMI
• XML?

3
CORBA - Objectives

• OS Independence
• Language Independence
• Remote Methods
• Static/Dynamic Invocations
• Distributed Services

4
Interoperability Requirements

• Standardization of
• Binary Formats in-memory
• APIs Programming Support
• IDL, Type Libraries, File Formats
• Data Representation CDR/NDR
• Transfer Protocol

5
What Does CORBA Provide?

• The PROs
• IDL
• Stub-skeleton generators
• Services APIs
• CDR
• IIOP

• And The CONs
• Complex
• Versioning
• Costly for large volumes
• Behavior mashalling

6
How can XML do it?

• Standardized Tags for Request/Response
• Parsers and DTDs
• HTTP / SMTP
• E.g. XML-RPC, SOAP
• A Geeks Pleasure!

7
Advantages

• Simplest Data Representation
• Hardware/Language/Vendor Neutral
• Simple and Human-readable
• Typing Flexibility
• Firewall Issues

8
Advantages.

• Extensible
• Domain Standards
• Namespaces
• Gateways
• XML Transforms
• Services will be available

9
Then Why Not XML?

• Distribution Support
• Resource location, control and management
• Services Transactions, Events, Security etc.
• Error Handling
• Non-text data
• Quality of Service Reliability
• Efficiency

10
XML With CORBA

• XML Structure
• CORBA Infrastructure
• XML Metadata Interchange
• XML Interfaces Components accepting/emitting
  XML documents
• E.g. Exchange of UML Models Between Design Tools.

11
Conclusion

• XML
• Structured Documents
• On-the-fly Documents
• Light-weight Applications
• Stateless Transactions
• Archiving
• CORBA better suited for complex enterprise
  applications.