It seems reasonable to summarise evolved
principles of service orientation
in one place. Following list comprises pairs of principle name -
definition. Each principle links to the related post discussing the
principle evolution.
Note: when 'service provider' entity
appears in the definition of
the principle, we mean that related activity may be performed either by
the service provider, or by the service own, or by the service steward.
Standardized
Definition of Service Contracts
Service contracts are in compliance with the standardised definitions
of the contract content types and represent mutual agreements between
service provider and service consumers
Service
Loose Coupling
Service contracts impose low consumer coupling requirements and are
themselves loosely decoupled with their surrounding environment via
execution contexts
Service
Abstraction
Service contract only contain essential service information that is
agreed between service provider or service owner and service consumer.
The information has to be sufficient for interacting with the service,
utilizing agreed service functionality and reaching agreed Real World
Effect
Service
Reusability
Services contain and express logic that can be reused in the execution
contexts; services can be positioned as reusable enterprise resources
Service
Relative Autonomy
Services exercise a relative level of control over their underlying
runtime execution environment; if the service does not own or control
used entities such as resources or other utilised services, the service
must posses contractual control over the use of those entities
Service
State Management
Services minimize resource consumption by deferring the management of
state information when necessary
Service
Composability
Services are effective composition participants as well as effective
composition containers, regardless of the size and complexity of the
composition
Service
Discoverability
Services are supplemented with communicative meta data by which they
can be effectively discovered and interpreted
Service
Execution Context
Services perform in surrounding business and technical runtime
environment that constitutes service execution context. The service
execution context can affect reachability, behaviour and results (Real
World Effect) of the services
The reviewed principles of Service
Orientation reflect contemporary
understanding of the Service Orientation as a methodology of
constructing Business and Technology parts of the organisations and as
the directive for designing corporate products. The latter are provided
by the organisation for its internal and external consumers in the form
of the business services.>>
You can find this
blog at:
http://www.ebizq.net/blogs/service_oriented/2009/02/principles_of_service_orientation_reviewed.php
Gervas
