A.5 General Architecture

A.5.7.1 Common data attributes

The attribute forms included, altreps, and superdcn, provide common data attributes that an application can use to interpret the data of the entity. These attributes can be used individually in attribute list definitions; each is a separate facility.

To be recognized as General Architecture data attributes, client notations that use the common data attributes must be derived, directly or indirectly, from the General Architecture GABrid notation form.

The attribute included entities (included) identifies entities that are included by reference from within data in a notation other than SGML (and therefore not recognized by the SGML parser). This information can be useful when moving or packing the data, as it allows the included entities to be found without knowing the notation of the data.

NOTE 485 A typical use of included entities referenced from notation data is a re-used object, such as symbols included by reference in a CGM level 4 graphic. Several entities could share these symbol definitions without duplicating them.

Another example is to support object-oriented programming by identifying methods that an application can invoke to access encapsulated data in the entity.

The attribute alternative representations (altreps) identifies equivalent representations of the entity, possibly using different data content notations.

NOTE 486 Alternative representations are not necessarily identical equivalents. They are typically used in fallback situations, when the preferred representation cannot be accessed or processed for some reason. However, the representations are presumed to be semantically equivalent from an information content standpoint, e.g., all the alternate representations of a graphic are more or less the same picture.

The attribute notation derivation source (superdcn) identifies a data content notation from which the current notation is derived.

NOTE 487 The superdcn attribute defines a derivation hierarchy within a single client document or architecture. Notations can also be derived from architectural notation forms. These two derivation hierarchies are independent of each other.

            <!-- Entities included from notation data -->
<![ %included; [
<!attlist #NOTATION
-- included --    -- Entities included from notation data --
                  -- Clause: A.5.7.1 --
   #ALL

   included       -- Entities included from notation data --
      CDATA       -- Lextype: ENTITIES --
      #IMPLIED    -- Default: no included entities --
>
]]><!-- included -->

                  <!-- Alternate Representations -->
<![ %altreps; [
<!attlist #NOTATION
-- altreps --     -- Alternate representations --
                  -- Clause: A.5.7.1 --
   #ALL

   altreps        -- Alternate representations --
                  -- Alternative representations of this entity --
      CDATA       -- Lextype: ENTITIES --
      #IMPLIED    -- Default: none --
>
]]><!-- altreps -->

                 <!-- Notation Derivation Source -->
<![ %superdcn; [
<!attlist #NOTATION
-- superdcn --    -- Notation derivation source --
                  -- Clause: A.5.7.1 --
   #ALL

   superdcn       -- Notation derivation source --
                  -- Notation on which this one is based --
      NAME        -- Lextype: NOTATION --
      #IMPLIED    -- Default: none --
>
]]><!-- superdcn -->