1. Chapter 4: Enterprise Architectures Service-Oriented Computing: Semantics, Processes, Agents – Munindar P. Singh and Michael N. Huhns, Wiley, 2005

2. Chapter 42Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and Michael Huhns Highlights of this Chapter Enterprise Integration JEE.NET Model Driven Architecture Legacy Systems

3. Chapter 43Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and Michael Huhns JEE Technology

4. Chapter 44Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and Michael Huhns.NET Technology

5. Chapter 45Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and Michael Huhns.NET Web Services COBOL Web service for multiplication (Mike’s joke) CLASS-ID. MULTIPLICATIONSERVICE. FACTORY. PROCEDURE DIVISION. METHOD-ID. MULTIPLY. DATA DIVISION. LINKAGE SECTION. 01 VAL-1 PIC S9(9) COMP-5. 02 VAL-2 PIC S9(9) COMP-5. 01 PRODUCT PIC S9(9) COMP-5. PROCEDURE DIVISION USING BY VALUE VAL-1 VAL-2 RETURNING PRODUCT. COMPUTE PRODUCT = VAL-1 * VAL-2. END METHOD MULTIPLY. END FACTORY. END CLASS MULTIPLICATIONSERVICE.

6. Chapter 46Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and Michael Huhns Legacy Systems A pejorative term for computing systems that Run on obsolete hardware and nonstandard networks Run poorly documented, unmaintainable software Consist of poorly modeled databases Support rigid user interfaces Notice that “legacy systems” is not synonymous with “mainframe” Mainframes have had a resurgence in the last decade: no longer obsolete hardware; often support modern OSs (Linux); not necessarily poorly modeled or rigid (some elements are obsolete or arcane) Most problems are with software whether on mainframes or other machines

7. Chapter 47Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and Michael Huhns How Legacy Systems Arise Proprietary software: not supporting industry standards (vendors who hope to lock in the market through incompatibility) Meaning embedded procedurally in the code Ad hoc changes to software in response to changing requirements, because of changes in laws, regulations, competition, or other business needs bugs

8. Chapter 48Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and Michael Huhns Legacy Systems: Pros and Cons Fulfill crucial business functions Run the world’s airline reservation systems Run most air traffic control programs Have dedicated users Represent huge investments in time and money Complicate reuse and sharing of data and programs cause redundancy, wasted effort, and integrity violations

9. Chapter 49Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and Michael Huhns Migration Updating technology is Essential A continual process All at once? Expensive Risky Brittle Frustrating for users Gradual change: dismantle legacy and build desired system hand-in-hand Install and test piecemeal

10. Chapter 410Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and Michael Huhns Applying Services Services Refactored from Legacy Backend Legacy Backend New Service Application Legacy Interface Error: services at too coarse a granularity

11. Chapter 411Service-Oriented Computing: Semantics, Processes, Agents - Munindar Singh and Michael Huhns Chapter 4 Summary Services must fit into existing architectures J2EE and.NET are architecturally quite similar Legacy systems provide the basis for many modern services They host key data and processes Interoperating with them is nontrivial Challenge: refactoring legacy capabilities to derive best value from resulting services