====== Views and Viewpoints ======

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Below is based on [[http://www.iso-architecture.org/ieee-1471/docs/all-about-ieee-1471.pdf|D. Emery, M. Maier, R. Hilliard, "All about IEE Std 1471" (2008)]]
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===== Definition =====
==== What it is ====

  * View: A representation of a whole system from the perspective of a related set of concerns. Views are modular allowing a view to utilize multiple notations and a model may be shared between multiple views. 
  * Viewpoints: Each view corresponds to only one viewpoint. Viewpoints define resources and rules for constructing views. 

**View** is
  * What you see
  * System/model specific

**Viewpoint** is
  * Where you look from
  * System/model generic. Therefore it is proposed that there is a //library// of viewpoints
  * 

==== What it is not ====
===== Rationale =====
The model of a system is often rich in information and addresses concerns from a wide range of stakeholders. To reduce perceived complexity, separate the concerns into different views. Views and Viewpoints provide a 'window' into the model that allows the viewer to obtain the information that they need.

Each view addresses one or more concerns of the stakeholders. If a view does not answer some stakeholder concerns then do not create view.

===== Pre-condition =====
===== Post-condition =====
===== Performance Qualities =====
===== Problem =====
===== Methodology =====
==== Method ====
Each architectural viewpoint is determined by:


  - Create a Viewpoint
    - Viewpoint name
    - Stakeholders addressed by the viewpoint
    - Architectural concerns "framed" by the viewpoint
    - Method used to construct, illustrate and analyze resulting view
    - Source (if any) of the viewpoint
    - (optional) Consistency or completeness checks associated with underlying method to be applied
    - (optional) Evaluation or analysis techniques to be applied
    - (optional) Heuristics, patters or guidelines which aid the synthesis of an associated view
  - Create a View
  - Apply a Conform edge from View to Viewpoint (edge is now replaced with a solid line with an empty arrow, similar to the Generalization edge)
  - Apply a Expose edge from View to element that the View exposes (e.g. "Requirements" package)

=== Heuristics ===
==== Process ====
===== Parts =====
  * Architectural Description (AD): Collection of products to document an architecture. AD addresses all identified stakeholders' concerns. Includes at least,
    * Identification of stakeholders and concerns
    * Selection and declaration of the viewpoints used
    * Views, each conforming to a viewpoint
    * Any known inconsistencies
    * Architectural rationale
  * Stakeholder: Individual, team or organization with interests in, or concerns relative to, a system
  * Concerns: Those stakeholders' interests which pertain to the development, operation, or other key characteristics of the system
===== Use Cases =====
==== Scenarios ====