Scope
Contrary to symbolic objects, physical ones exist and can be used on their own, even if their appearance and modus operandi may hold some symbolic dimensions.
Objects and their Capabilities
Physical objects have a concrete appearance independent of their symbolic representation which only take into account that subset of features targeted by business concerns. Since the same objects can pertain to different concerns, they may be associated with an unlimited number of facets: whatever its simplicity, no physical object can be reduced to its representation and the possibility of additional aspects should always be assumed.
Whereas inanimate physical objects can be associated with documental identities, live ones always keep an identity of their own, independently of the documental ones they may receive.
On the other side, physical objects are not necessarily identified by a business concern and they can also occur as unidentified individuals or even as lumps; in that case their management will require the introduction of symbolic containers.
Agents are active physical objects, i.e they have the capacity to generate events and initiate interactions on their own. If organizational concerns are to be taken into account, it may be helpful to define as agents active objects enabled with organizational responsibilities (e.g users) as opposed to devices or systems. It must be noted that, as far as systems are concerned, humans may be lumped with devices if they are deprived of social or organizational responsibilities.
Depending on business requirements, physical objects can therefore be easily classified with few straightforward questions:
- Is the object natural or man-made ? and in case of artifact, is it associated with a symbolic content ?
- Is the object the source of some relevant behavior ?
- If it’s a natural object with behavior, is it granted some organization responsibility ?
Objects and Systems Architectures
The proper identification, qualification and traceability of physical objects are central to architecture driven system modelling:
- Every physical business object may have different facets represented by documentary objects, and those facets are meant to change over time.
- The physicality of business objects will set the basis of architectural constraints regarding location and synchronization.
- The distinction between active and passive ones is arguably a primary factor for system technical architecture, and changes must be supported independently of what happens to functional architecture.
- The distinction between organizational agents and mechanical ones is obviously a primary factor for functional architecture, and changes must be supported independently of what happens to technical architecture.
- Distributed systems and services oriented architectures entail the collaboration of agents whose implementation may change without impacting the services they provide.