BPMN21 — Inconsistencies concerning Flow Elements

i) Chapter/Section 8.3.7. Page 86. It says:
“FlowElement is the abstract super class for all elements that can appear in a Process flow, which are FlowNodes (see page 99, which consist of Activities (see page 155), Choreography Activities (see page 331) Gateways (see page 295), and Events (see page 240)), Data Objects (see page 212), Data Associations (see page 228), and Sequence Flows (see page 97).”

In other words, Flow Elements are:
a) Flow Node
a.1) Activity
a.2) Choreography Activity
a.3) Gateway
a.4) Event
b) Data Object
c) Data Association
d) Sequence Flow

ii) Chapter/Section 8.3.7. Page 87. Figure 8.22
According to classes and their associations Flow Elements are:
a) Flow Node
a.1) Activity
a.2) Choreography Activity
a.3) Gateway
a.4) Event
b) Data Object
c) DataStoreReference
d) Sequence Flow

iii) Chapter/Section 8.3.8. Page 88. It says:
“Basically, a FlowElementsContainer contains FlowElements, which are Events (see page 240), Gateways (see page 295), Sequence Flows (see page 97), Activities (see page 155), and Choreography Activities (see page 331).”

In other words, Flow Elements are:
a) Event
b) Gateway
c) Sequence Flow
d) Activity
e) Choreography Activity

iv) Chapter/Section 8.3.8. Page 89. Table 8.45. It says: “Flow elements are Events, Gateways, Sequence Flows, Activities, Data Objects, Data Associations, and Choreography Activities.”

In other words, Flow Elements are:
a) Event
b) Gateway
c) Sequence Flow
d) Activity
e) Data Object
f) Data Association
g) Choreography Activity

v) Chapter/Section 10.3.1. Page 212. Figure 10.51.
According to classes and their associations:
DataObjectReference is subclass of FlowElement
DataObject is subclass of FlowElement

vi) Chapter/Section 10.3.1. Page 216. Figure 10.55.
According to classes and their associations:
DataStoreReference is subclass of FlowElement
DataStore is subclass of RootElement

COMMENTS:

In , (ii), (iii) and (iv) the lists of Flow Elements are different.

In and (iv) DataAssociation is mentioned as a type of FlowElement, but it is not correct. See Figure 10.64 (p. 229), where it is shown that DataAssociation is direct subclass of BaseElement. Furthermore, DataAssociation in not shown as a subclass of FlowElement in (ii).

In (ii) Data Association is replaced by DataStoreReference

In (iii) Data Object, Data Association, and Data Store Reference are not mentioned.

In (iv) DataObjectReference, DataStore and DataStoreReference are not mentioned.

In (v) DataObjectReference is subclass of FlowElement, but it is not mentioned in , (ii), (iii) and (iv).

In (vi) DataStore is not a subclass of FlowElement, as DataObjectReference, DataObject and DataStoreReference. In the document it is not explained the reason for this exclusion.

SUGGESTIONS:

It seems that Flow Elements are:

a) Flow Node
a.1) Activity
a.2) Choreography Activity
a.3) Gateway
a.4) Event
b) Data Object
c) Data Object Reference
d) Data Store
e) Data Store Reference
f) Sequence Flow

If this is the case, then , (ii), (iii), (iv), and (vi) should be updated accordingly.

In remove Data Association
add Data Object Reference, Data Store and Data Store Reference.

In (ii) add Data Object Reference, and Data Store.

In (iii) add Data Object, Data Object Reference, Data Store, and Data Store Reference.

In (iv) remove Data Association
add Data Object Reference, Data Store and Data Store Reference.

In (vi) remove generalization from DataStore to RootElement, and add generalization from DataStore to FlowElement.

(v) doesn’t require modifications