Service Modeling Based on SOA: Concepts, Technology, Design by Thomas Erl MIS 181.9: Service Oriented Architecture 2 nd Semester,

Service-Oriented Development ► Development of a service-oriented solution ► General Steps ► Analysis ► Design ► Implementation (Development, Testing, Deployment) ► Maintenance

Service-Oriented Analysis ► Define Business Requirements ► Data Gathering ► Can be focused on Tasks or Entities ► Identify Automation Systems ► Scope Definition ► Model Candidate Services ► Service Modeling

Defining Business Services Task-Centric vs Entity-Centric

Service-Oriented Analysis ► Goal: Figure out what has to be considered in the Design Process ► Identify Services ► Start by identifying CANDIDATE SERVICES ► Service Candidates are the outputs of Service Modeling

Service Modeling 1. Decompose business processes 2. Identify operation candidates 3. Define orchestration logic 4. Create service candidates 5. Refine and apply service orientation 6. Identify service compositions

Service Modeling 7. Revise operation grouping 8. Analyze processing requirements 9. Identify application service operations 10. Create application service candidates 11. Revise service compositions 12. Revise operation grouping

Decompose Business Processes ► Breakdown process into smaller steps ► Create Process models ► DFDs ► BPM models

Example: Invoice Submission Process 1. Create electronic invoice. 2. Issue electronic invoice. 3. Export electronic invoice to network folder. 4. Poll network folder. 5. Retrieve electronic invoice. 6. Transform electronic invoice to XML document. 7. Check validity of invoice document. If invalid, end process. 8. Check if it is time to verify TLS metadata. 9. If required, perform metadata check. If fails, end process.

Identify Operation Candidates ► Remove those that can not be part of the automated solution ► Filter list of business processes

Filter Original List of Processes 1. Create electronic invoice. (Manual step done by accounting clerk) 2. Issue electronic invoice. (Manual step done by accounting clerk) 3. Export electronic invoice to network folder. (Currently a custom developed extension of the legacy system. Could be made part of a generic service candidate.) 4. Poll network folder. (Currently a custom developed component. Could be made part of a service candidate.) 5. Retrieve electronic invoice. (Same as previous.)

Filter Original List of Processes 6. Transform electronic invoice to XML document. (Same as previous.) 7. Check validity of invoice document. If invalid, end process. (Is currently being performed as part of the Invoice Submission Service's parsing routine. No foreseeable need to change this.) 8. Check if it is time to verify TLS metadata. (Is currently being performed as part of the Invoice Submission Service's parsing routine. Looks like a potentially reusable operation candidate. Could be moved to a separate service candidate.) 9. If required, perform metadata check. If fails, end process. (Same as previous.)

Abstract Orchestration Logic ► Business Rules ► Conditional Logic ► Exception Logic ► Sequence Logic

Abstract Orchestration Logic 1. If the invoice document is valid, proceed with the metadata check step. 2. If the invoice document is invalid, end process. 3. If the interval period for performing a metadata check has completed, proceed to the perform metadata check step. 4. If the interval period has not completed, skip the perform metadata check step. 5. If the PO document is valid, proceed with the transform PO document step. 6. If the PO document is invalid, end process.

Create Business Service Candidates ► Review remaining processes ► Determine logical grouping ► Each grouping = service candidate

Create Business Service Candidates ► Legacy System Service 1. Export electronic invoice to network folder. 2. Import electronic PO into accounting system. 3. Send PO to accounting clerk's work queue. ► Invoice Processing Service 1. Poll network folder for invoice. 2. Retrieve electronic invoice. 3. Transform electronic invoice to XML document. 4. Check validity of invoice document. If invalid, end process.

Create Business Service Candidates ► Metadata Checking Service 1. Check if it is time to verify TLS metadata. 2. If required, perform metadata check; if metadata check fails, end process. ► PO Processing Service 1. Receive PO document 2. Validate PO document 3. If PO document is invalid, send rejection notification and end process. 4. Transform PO XML document into native electronic PO format.

Create Business Service Candidates Legacy System Service Invoice Process- ing Service Metadat a Check- ing Service PO Process- ing Service

Refine and Apply Service-Orientation Principles ► Important properties in the modeling stage ► Reusability ► Autonomy ► Identify potentially reusable and autonomous services

Refine and Apply Service-Orientation Principles Legacy System Service Invoice Process- ing Service Metadat a Check- ing Service PO Process- ing Service Polling Notifica- tion Service Transform Accounting Documents Service

Refine and Apply Service-Orientation Principles ► Polling Notification Service 1. Poll folder for new documents. 2. If documents arrive for which there are subscribers, issue notifications. ► Transform Accounting Documents Service ► Transform XML documents into native format ► Transform native documents to XML

Refine and Apply Service-Orientation Principles ► Metadata Checking Service 1. Check if it is time to verify TLS metadata. If it is time, perform metadata check. 2. If required, perform metadata check; if metadata check fails, end process. Issue notification. ► PO Processing Service 1. Receive PO document 2. Validate PO document 3. If PO document is invalid, send rejection notification and end process. 4. Transform PO XML doc. into native electronic PO format.

Refine and Apply Service-Orientation Principles ► Legacy System Service 1. Export electronic invoice to network folder. 2. Import electronic PO into accounting system. 3. Send PO to accounting clerk's work queue. ► Invoice Processing Service 1. Poll network folder for invoice. 2. Retrieve electronic invoice. 3. Transform electronic invoice to XML document. 4. Check validity of invoice document. If invalid, end process.

Identify Service Compositions Apply Service Layer Principle

Service Layers ► Application Service Layer ► Express technology-specific functionality ► Provide reusable functions related to processing data ► Business Service Layer ► Implementation of the business service model ► Represents business logic ► Orchestration Service Layer ► Defines business rules and service execution sequence logic ► Adds complexity to SOA implementation

Service Composition Defined