1、 . i EIMS-116 Interim Standard i . j .-: :. .: . .;.: “.“ ;. . . , : :;*:y.% :;:i:,;. . .:s. . . F L_) Figure 3 Conventions for Representing Meta-relationships Full details of the CDIF Graphical Notation used in the Meta-model and the Meta-meta-model can be found in EIAIIS-IO7 CDIF - Framework for M
2、odeling and Extensibility. To aid in the understanding of some of the concepts modeled in this subject area, instance diagrams have been used. These diagrams differ from those described above in that an instance diagram depicts one or more occurrences or instances of meta-entities and meta-relations
3、hips depicted in the diagrams previously described. Where one of the diagrams previously described Structure of Subject Area Definition Copyright Government Electronics all names indented below a given name are subtypes of that meta-object. For example, if Car and Truck are both subtypes of Vehicle,
4、 this would be shown as follows: Vehicle CU Truck A meta-entity or meta-relationship and all its subtypes can be duplicated in the hierarchy due to multiple inheritance. Where this occurrs, the duplicate entries are shown in italics. The overall AttributableMetaObject supbrtype, Rootobject, defined
5、in EIA/IS-lll CDIF - IntegratedMeta-model - Foundation Subject Area, is shown at the top of the hierarchy. Where a page break occurs in the list, all the supertypes of the first meta-entity or meta- relationship on the new page are repeated for clarity with a shaded background. 3.2.5 MetaEntity and
6、MetaRelationship Summaries Summaries are given of all the meta-entities and meta-relationships used in the Subject Area. The meta-entity definitions are given first, in alphabetical order, followed by the meta-relationship definitions, also in alphabetical order. For each meta-entity used in the sub
7、ject area, all the meta-attributes, both inherited and local, are listed. The inherited meta-attributes are shown first, in italics, sequenced alphabetically within parent meta-entity. The local meta-attributes are then listed alphabetically in normal font. The optionality, whether mandatory or opti
8、onal, of each meta-attribute is given. For each meta-relationship all the meta-attributes are listed sequenced alphabetically. Inherited and local meta-attributes are shown in the same way as for meta-entities. The optionality of each meta-attribute is given. 3.3 Structure of Subject Area Detailed D
9、efinitions 3.3.1 Summary The Subject Area Detailed Definitions section consists of the following sub-sections: O Subject Area Definition O MetaRelationship Definitions O MetaEntity Definitions Structure of Subject Area Definition Copyright Government Electronics both meta-entity and meta- Structure
10、of Subject Area Definition Copyright Government Electronics a state at a certain level of abstraction may be refined into a number of lower-level states, transitions, attributes, events and conditions. The higher-level transitions and attributes are bound to the interface the lower level state machi
11、ne exposes. If a structured state is entered, at least one of its substates is also entered. For the case where the structured state contains sequentially executing substates, the first (or next if the sequence was interrupted) substate is entered. For the case of concurrently executing substates, a
12、ll substates are entered. For the case of alternate substates, exactly one substate is entered. When a structured state is active, it is not possible that none of its substates is active. 4.1.4 Transitions Transitions represent potential traces of state changes between states. At any instant of time
13、, a transition may or may not be taken in a state/event model. Transitions can be triggered by the occurrence of an event, such as when a condition becomes true or a set time occurs. For a transition to occur, the system, entity or object must be in a state from which the transition can be taken. As
14、 a result of a transition being taken, an action may be performed. This subject area does not support the concept of decomposing transitions. It does, however, support the concept of splitting and merging transitions. 4.1.5 Action An action is a procedure that may be performed as a result of an even
15、t occurring, such as a condition becoming true, or a transition being taken. Actions usually act on Attributes. For example, the procedure “assign 5 to Attribute X” could be an Action. Actions may be elemental (primitive) or structured. This subject area includes a number of primitive actions, such
16、as assigment actions. Structured actions contain other actions which may be performed in sequence, in parallel, or as alternates. 4.1.6 Events and Conditions At any point in time, a certain event may or may not occur. For example, at any point in time, the event “temperature is crossing the O degree
17、 mark” may happen. On the contrary, conditions represent boolean values which persist over time. For example, “temperature is higher than O degrees” would be a condition. Both concepts are supported in this subject area. Also, the concept of a buffered event is supported. A buffered event is an even
18、t whose occurrence is stored until it can be processed. For example, in a telecommunication system, the event “customer pressed the 1 key” may be stored. Subject Area Overview Copyright Government Electronics & Information Technology Association Reproduced by IHS under license with GEIA Not for Resa
19、leNo reproduction or networking permitted without license from IHS-,-,-CDIF - Integrated Meta-model - StateRvent Model Subject Area CDIF-DFtAF-STEV-VO7, June 1996 Page 17 4.1.7 The General Structuring Mechanism 4.1.7.1 Introduction Support for the decomposition and structuring of objects into other
20、objects, and the reuse of definitions, is provided by a general structuring mechanism. This mechanism is also used in other CDIF subject areas. In this subject area the following concepts may be structured: States, Actions, Attributes, Events and Conditions. Structuring of those concepts is performe
21、d using the general structuring mechanism because their definitions may be used by several objects in different contexts. 4.1.7.2 Meta-entities and Meta-relationships The general structuring mechanism makes use of the following meta-entities: o ComponentObject O DeJinitionObject o ReferencedElement
22、o Equivalencese t and the following meta-relationships: o DefinitionObject. Contains. ConqonentObject O ComponentObject. References. DeJinitionObject O ReferencedElement. DejnesPath. ComponentObject O Equivalencese t. HaMember. ComponentObject. Figure 6 shows the meta-model for the general structuri
23、ng mechanism. Subject Area Detailed Definitions Copyright Government Electronics & Information Technology Association Reproduced by IHS under license with GEIA Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-CDIF - Integrated Meta-modei - StateEvent Model Subject A
24、rea CDIF-DRAFT-STEV-VO7, June 1996 Page 18 ontains 0:I Definition DefinesPa Object . O:N I 1 HasMember O:N Figure 6 General Structuring Mechanism Referenced Element 4.1.7.3 Definitionobject and ComponentObject Equivalence Set Definitionobject serves as an abstract supertype for all decomposition and
25、 structure definitions that may be reused. A Definitionobject represents the definition of a ComponentObject, using meta-relationshi p ComponentObject.References.Definition0bject. A DefinitionObject may contain ComponentObjects, using the Definitionobject. Contains.ComponentObject meta- relationship
26、. The ComponentObjects contained in a DefznitionObject represent the components of the definition. Both ComponentObject and DefznitionObject represent abstract concepts and thus shall not be instantiated. Instead, appropriate subtypes, provided by this or other subject areas, are used. A subtype of
27、DefznitionObject may be referenced by any number of ComponentObjects indicating that all those ComponentObjects share the same definition. Instances of the subtypes of ComponentObject are used to describe the structure of a DefinitionObject. There may be any number of ComponentObjects per Definition
28、object. Subject Area Overview Copyright Government Electronics & Information Technology Association Reproduced by IHS under license with GEIA Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-CDIF - Integrated Meta-model - StateEvent Model Subject Area CDiF-DRAFT-STE
29、V-V07, June 1996 Page 19 State a - State Definition References State Figure 7 States sharing the same structured definition For example, if a structure is built containing two components that share the same definition, the structured DejnitionObject will contain two distinct ComponentObjects which r
30、efer to the same shared DejnitionObject. i In this subject area, DejnitionObjects may contain one or more instances of one or more ComponentObjects. The allowed components, in addition to ReferencedEZement and EquivaZenceSet, for a given DeJinitionObject are shown in Table 5. For example, a State ma
31、y reference a StateDejnition that contains States and Transitions. This represents the fact that the State is refined into lower-level states and transitions through its definition. The StateDefnition may be shared by another State which also refers to this StateDeJinition using ComponentObject, Ref
32、erences. DejnitionObject. Contains b Table 5 Allowable DeJinitionObject components Contains ActionDefinition ConditionDataType EventDataTwe State X A ComponentObject Action Attribute Condition Event State Transition TransitionPort Action Attribute Condition Event Condition Event State Y Subject Area
33、 Detailed Definitions Copyright Government Electronics & Information Technology Association Reproduced by IHS under license with GEIA Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-CDIF - Integrated Meta-model - Statemvent Model Subject Area CDIF-DMF-STEV-VO7, Jun
34、e 1996 Page 20 I I U I State De?i%on contiains, o Q&f The general structuring mechanism ensures that, for example, the instances of the components of one State are different from those of another State even if both States share the same StateDejnition. This applies equally for all DejnitionObjects.
35、It can also be used to speci, using the EquivaZenceSet meta-entity, that two components in different reuse situations are actually the same instance (see 4.1.1 1 Identical Instances in Shared Definitions). 4.1.8 State Decomposition and Definition States are represented using the meta-entity States t
36、hat is a subtype of ComponentObject. States definitions are represented using meta-entity StateDefinition, a subtype of Definitionobject. Figure 8 shows an example of a state decomposition. State P decomposes into Q, R and S. R and S share the same decomposition into T and U. The general structuring
37、 mechanism requires that each process refers to a process definition. States cannot contain States or any other ComponentObject directly, the StateDejnition contains the ComponentObjects. Sharing definitions does not imply anything about the instances. For example, the States Tin the decomposition o
38、f R shares only its structure with S, not its data or state. State I - R bermirion T 1 Figure 8 A states decomposition For the definition of leaf states (i.e., states which are not decomposed into other states) an instance of the meta-entity StateDejnition is used which does not contain any States,
39、Attributes, Actions or Transitions. Subject Area Overview Copyright Government Electronics & Information Technology Association Reproduced by IHS under license with GEIA Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-CDIF - Integrated Meta-model - StateEvent Model
40、 Subject Area CDIF-DRAFT-STEV-VO7, June 1996 Page 21 4.1.9 Action Decomposition and Definition Analogous to the structuring of states, Actions are also structured using the general structuring mechanism. An ActionDeJinition represents the potential structure of a Action. An Action may be a structure
41、d Action containing other Actions as members or completely unstructured. Figure 9 shows an example for a structured Action where Actionfl andf2 share the same structured ActionDefinition. This ActionDefinition indicates that bothfl andf2 each contain an Action x, an Action y and a Action z. Each Act
42、ion has an ActionDeBnition. Actions x and y share an ActionDeJinition called action-def2. - Action action-defl Operator: AM) f2 v Action Action Action X Y z References References r I Attribute I action-def3 , , contain$ , , contain4 , , #ontains , + Figure 9 Structured Actions The sharing of ActionD
43、efinitions does not imply anything about the data on the Actions which share the same defnitions. In this case, for example, the Attributesfi-xa (Attribute a on subaction x of actionfl),fl.y.a andf2.u are completely unrelated. If the values of the Attributesfl.xa andfl.y.a are the same, an Equivalen
44、ceset with two ReferencedElements would be used. This Equivalenceset would be contained in ActionDefinition action-defl . (See section 4.1.1 1 , Identical Instances in Shared Definitions.) Subject Area Detailed Definitions Copyright Government Electronics & Information Technology Association Reprodu
45、ced by IHS under license with GEIA Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-CDIF - Integrated Meta-model - StateEvent Model Subject Area CDIF-DRAFT-SEV-VO7, June 1996 Pam 22 4.1.10 Accessing a Specific Component in a Shared Definition If a ComponentObject in
46、 a shared Definitionobject needs to be referenced, a simple reference is not sufficient because definitions can be shared and it would be not clear whose structured objects component is meant if its definition is reused. Instead, the full path to the ComponentObject, traversing the loop Componentobj
47、ect, Component0 bject. Re ferences. Definition0 bject, Definitionobject, Definitionobject. Contains. ComponentObject, is needed to uniquely identify a specific instance. This path is formed by the associative meta-entity ReferencedEZement and the meta-relationship ReferencedElement.DefinesPath.Compo
48、nent0bject. The ReferencedElement is the Componentobject which refers to the specific Componentobject contained in a shared Definitionobject. The meta-relationship ReferencedElement.DejnesPath. Componentobject carries a meta-attribute SequenceNumber which describes the sequence in which the path is
49、traversed. An example of this is shown in Figure 10 for the case of an assigment action. Figure 1 1 shows the corresponding instance diagram. In this example, there are two instances of the x component action, one in Action a (called ax), and one in Action b (called b.x). in order to refer to the x component of a (as opposed to the x component of b) a ReferencedEZement is created which identifies the complete path consisting of a and x, using instances of the
