Task: Document Service State-Management Decisions

This task defines and specifies the services and structure of a service-oriented solution in terms of collaborations of contained design elements and external subsystems/interfaces.

Purpose

To define the services and structure of a service-oriented solution in terms of collaborations of contained design elements and external subsystems/interfaces.
To analyze the service for commonality and variability (see Guideline: Variability Analysis).
To document the specification of services.
To determine the dependencies and the communication between services.

Relationships

Roles	Main: Designer	Additional: Software Architect	Assisting:
Inputs	Mandatory: Design Model Service Model Software Architecture Document Supplementary Specifications	Optional: Project-Specific Guidelines	External: None
Outputs	Design Model Service Model

Main Description

This task refines the set of Artifact: Service Specifications identified and qualified during Activity: Existing Asset Analysis and provides additional structure and detail. This design-level detail includes the interface, message and composition of services and the allocation of services to providers.

Steps

Document State-Management Requirements

Although individual services are considered stateless, compositions often have requirements to maintain state information across the invocation of the composed services. The choreographer of the services is often responsible for the management of state. Alternatively, a component that implements and realizes multiple related services or operations on services may need to maintain state between invocations for performance reasons.

State Management in SOA environment can be considered to fall into three main categories:

Transaction State - where a service has an open transaction during a conversation with a client.
Security State - where a security context is held open during a conversation with a client.
Functional State - where the conversation with a client involves a number of related operations.

For more information see the Guideline: State Management for Services.

Properties

Multiple Occurrences
Event Driven
Ongoing
Optional
Planned
Repeatable

More Information

Concepts	Service Composition and Choreography Service-Oriented Architecture Solution Partitioning
Guidelines	Service Realization - BPEL services in a SOA application
Tool Mentors	Creating a Service Model using RSA-W