- •1 Scope
- •1.1 General
- •2 Conformance
- •2.1 General
- •2.2 Process Modeling Conformance
- •2.2.1 BPMN Process Types
- •2.2.2 BPMN Process Elements
- •Descriptive Conformance Sub-Class
- •Analytic Conformance Sub-Class
- •Common Executable Conformance Sub-Class
- •2.2.3 Visual Appearance
- •2.2.4 Structural Conformance
- •2.2.5 Process Semantics
- •2.2.6 Attributes and Model Associations
- •2.2.7 Extended and Optional Elements
- •2.2.8 Visual Interchange
- •2.3 Process Execution Conformance
- •2.3.1 Execution Semantics
- •2.3.2 Import of Process Diagrams
- •2.4 BPEL Process Execution Conformance
- •2.5 Choreography Modeling Conformance
- •2.5.1 BPMN Choreography Types
- •2.5.2 BPMN Choreography Elements
- •2.5.3 Visual Appearance
- •2.5.4 Choreography Semantics
- •2.5.5 Visual Interchange
- •2.6 Summary of BPMN Conformance Types
- •3 Normative References
- •3.1 General
- •3.2 Normative
- •3.3 Non-Normative
- •Activity Service
- •BPEL4People
- •Business Process Definition Metamodel
- •Business Process Modeling
- •Business Transaction Protocol
- •Dublin Core Meta Data
- •ebXML BPSS
- •Open Nested Transactions
- •SOAP 1.2
- •UDDI
- •WfMC Glossary
- •Web Services Transaction
- •Workflow Patterns
- •WSBPEL
- •WS-Coordination
- •WSDL
- •WS-HumanTask
- •XML 1.0 (Second Edition)
- •XML-Namespaces
- •XML-Schema
- •XPath
- •XPDL
- •4 Terms and Definitions
- •5 Symbols
- •6 Additional Information
- •6.1 Conventions
- •6.1.1 Typographical and Linguistic Conventions and Style
- •6.1.2 Abbreviations
- •6.2 Structure of this Document
- •6.3 Acknowledgments
- •Submitting Organizations
- •Supporting Organizations
- •Special Acknowledgments
- •7 Overview
- •7.1 General
- •7.2 BPMN Scope
- •7.2.1 Uses of BPMN
- •Private (Internal) Business Processes
- •Public Processes
- •Collaborations
- •Choreographies
- •Conversations
- •Diagram Point of View
- •Understanding the Behavior of Diagrams
- •7.3 BPMN Elements
- •7.3.1 Basic BPMN Modeling Elements
- •7.3.2 Extended BPMN Modeling Elements
- •7.4 BPMN Diagram Types
- •7.5 Use of Text, Color, Size, and Lines in a Diagram
- •7.6 Flow Object Connection Rules
- •7.6.1 Sequence Flow Connections Rules
- •7.6.2 Message Flow Connection Rules
- •7.7 BPMN Extensibility
- •7.8 BPMN Example
- •8 BPMN Core Structure
- •8.1 General
- •8.2 Infrastructure
- •8.2.1 Definitions
- •8.2.2 Import
- •8.2.3 Infrastructure Package XML Schemas
- •8.3 Foundation
- •8.3.1 Base Element
- •8.3.2 Documentation
- •8.3.3 Extensibility
- •Extension
- •ExtensionDefinition
- •ExtensionAttributeDefinition
- •ExtensionAttributeValue
- •Extensibility XML Schemas
- •XML Example
- •8.3.4 External Relationships
- •8.3.5 Root Element
- •8.3.6 Foundation Package XML Schemas
- •8.4 Common Elements
- •8.4.1 Artifacts
- •Common Artifact Definitions
- •Artifact Sequence Flow Connections
- •Artifact Message Flow Connections
- •Association
- •Group
- •Category
- •Text Annotation
- •XML Schema for Artifacts
- •8.4.2 Correlation
- •CorrelationKey
- •Key-based Correlation
- •Context-based Correlation
- •XML Schema for Correlation
- •8.4.3 Error
- •8.4.4 Escalation
- •8.4.5 Events
- •8.4.6 Expressions
- •Expression
- •Formal Expression
- •8.4.7 Flow Element
- •8.4.8 Flow Elements Container
- •8.4.9 Gateways
- •8.4.10 Item Definition
- •8.4.11 Message
- •8.4.12 Resources
- •8.4.13 Sequence Flow
- •Flow Node
- •8.4.14 Common Package XML Schemas
- •8.5 Services
- •8.5.1 Interface
- •8.5.2 EndPoint
- •8.5.3 Operation
- •8.5.4 Service Package XML Schemas
- •9 Collaboration
- •9.1 General
- •9.2 Basic Collaboration Concepts
- •9.2.1 Use of BPMN Common Elements
- •9.3 Pool and Participant
- •9.3.1 Participants
- •PartnerEntity
- •PartnerRole
- •Participant Multiplicity
- •ParticipantAssociation
- •9.3.2 Lanes
- •9.4 Message Flow
- •9.4.1 Interaction Node
- •9.4.2 Message Flow Associations
- •9.5 Conversations
- •9.5.1 Conversation Node
- •9.5.2 Conversation
- •9.5.3 Sub-Conversation
- •9.5.4 Call Conversation
- •9.5.5 Global Conversation
- •9.5.6 Conversation Link
- •9.5.7 Conversation Association
- •9.5.8 Correlations
- •9.6 Process within Collaboration
- •9.7 Choreography within Collaboration
- •9.8 Collaboration Package XML Schemas
- •10 Process
- •10.1 General
- •10.2 Basic Process Concepts
- •10.2.1 Types of BPMN Processes
- •10.2.2 Use of BPMN Common Elements
- •10.3 Activities
- •Sequence Flow Connections
- •Message Flow Connections
- •10.3.1 Resource Assignment
- •Resource Role
- •Expression Assignment
- •Parameterized Resource Assignment
- •10.3.2 Performer
- •10.3.3 Tasks
- •Service Task
- •Send Task
- •Receive Task
- •User Task
- •Manual Task
- •Business Rule
- •Script Task
- •10.3.4 Human Interactions
- •Notation
- •Manual Task
- •User Task
- •Rendering of User Tasks
- •Human Performers
- •Potential Owners
- •XML Schema for Human Interactions
- •Examples
- •10.3.5 Sub-Processes
- •Embedded Sub-Process (Sub-Process)
- •Reusable Sub-Process (Call Activity)
- •Event Sub-Process
- •Transaction
- •Ad-Hoc Sub-Process
- •10.3.6 Call Activity
- •Callable Element
- •10.3.7 Global Task
- •Types of Global Task
- •10.3.8 Loop Characteristics
- •Standard Loop Characteristics
- •Multi-Instance Characteristics
- •Complex Behavior Definition
- •10.3.9 XML Schema for Activities
- •10.4 Items and Data
- •10.4.1 Data Modeling
- •Item-Aware Elements
- •Data Objects
- •DataObject
- •States
- •Data Objects representing a Collection of Data
- •Visual representations of Data Objects
- •Lifecycle and Accessibility
- •Data Stores
- •Properties
- •Lifecycle and Accessibility
- •Data Inputs and Outputs
- •Data Input
- •States
- •Data Output
- •States
- •Service Task Mapping
- •Send Task Mapping
- •Receive Task Mapping
- •User Task Mapping
- •Call Activity Mapping
- •Script Task Mapping
- •Events
- •InputSet
- •OutputSet
- •Data Associations
- •DataAssociation
- •Assignment
- •DataInputAssociation
- •DataOutputAssociation
- •Data Objects associated with a Sequence Flow
- •10.4.2 Execution Semantics for Data
- •Execution Semantics for DataAssociation
- •10.4.3 Usage of Data in XPath Expressions
- •Access to BPMN Data Objects
- •Access to BPMN Data Input and Data Output
- •Access to BPMN Properties
- •For BPMN Instance Attributes
- •10.4.4 XML Schema for Data
- •10.5 Events
- •10.5.1 Concepts
- •Data Modeling and Events
- •Common Event attributes
- •Common Catch Event attributes
- •Common Throw Event Attributes
- •Implicit Throw Event
- •10.5.2 Start Event
- •Start Event Triggers
- •Start Events for Top-level Processes
- •Start Events for Sub-Processes
- •Start Events for Event Sub-Processes
- •Attributes for Start Events
- •Sequence Flow Connections
- •Message Flow Connections
- •10.5.3 End Event
- •End Event Results
- •Sequence Flow Connections
- •Message Flow Connections
- •10.5.4 Intermediate Event
- •Intermediate Event Triggers
- •Intermediate Events in Normal Flow
- •Intermediate Events Attached to an Activity Boundary
- •Attributes for Boundary Events
- •Activity Boundary Connections
- •Sequence Flow Connections
- •Message Flow Connections
- •10.5.5 Event Definitions
- •Event Definition Metamodel
- •Cancel Event
- •Compensation Event
- •Conditional Event
- •Error Event
- •Escalation Event Definition
- •Link Event Definition
- •Message Event Definition
- •Multiple Event
- •None Event
- •Parallel Multiple Event
- •Signal Event
- •Terminate Event
- •Timer Event
- •10.5.6 Handling Events
- •Handling Start Events
- •Handling Events within normal Sequence Flow (Intermediate Events)
- •Handling Events attached to an Activity (Intermediate boundary Events and Event Sub-Processes)
- •Interrupting Event Handlers (Error, Escalation, Message, Signal, Timer, Conditional, Multiple, and Parallel Multiple)
- •Non-interrupting Event Handlers (Escalation, Message, Signal, Timer, Conditional, Multiple, and Parallel Multiple)
- •Handling End Events
- •10.5.7 Scopes
- •10.5.8 Events Package XML Schemas
- •10.6 Gateways
- •10.6.1 Sequence Flow Considerations
- •10.6.2 Exclusive Gateway
- •10.6.3 Inclusive Gateway
- •10.6.4 Parallel Gateway
- •10.6.5 Complex Gateway
- •10.6.6 Event-Based Gateway
- •10.6.7 Gateway Package XML Schemas
- •10.7 Compensation
- •10.7.1 Compensation Handler
- •10.7.2 Compensation Triggering
- •10.7.3 Relationship between Error Handling and Compensation
- •10.8 Lanes
- •10.9 Process Instances, Unmodeled Activities, and Public Processes
- •10.10 Auditing
- •10.11 Monitoring
- •10.12 Process Package XML Schemas
- •11 Choreography
- •11.1 General
- •11.2 Basic Choreography Concepts
- •11.3 Data
- •11.4 Use of BPMN Common Elements
- •11.4.1 Sequence Flow
- •11.4.2 Artifacts
- •11.5 Choreography Activities
- •11.5.1 Choreography Task
- •11.5.2 Sub-Choreography
- •The Parent Sub-Choreography (Expanded)
- •11.5.3 Call Choreography
- •11.5.4 Global Choreography Task
- •11.5.5 Looping Activities
- •11.5.6 The Sequencing of Activities
- •11.6 Events
- •11.6.1 Start Events
- •11.6.2 Intermediate Events
- •11.6.3 End Events
- •11.7 Gateways
- •11.7.1 Exclusive Gateway
- •11.7.2 Event-Based Gateway
- •11.7.3 Inclusive Gateway
- •11.7.4 Parallel Gateway
- •11.7.5 Complex Gateway
- •11.7.6 Chaining Gateways
- •11.8 Choreography within Collaboration
- •11.8.1 Participants
- •11.8.2 Swimlanes
- •Choreography Task in Combined View
- •Sub-Choreography in Combined View
- •11.9 XML Schema for Choreography
- •12 BPMN Notation and Diagrams
- •12.1 BPMN Diagram Interchange (BPMN DI)
- •12.1.1 Scope
- •12.1.2 Diagram Definition and Interchange
- •12.1.3 How to Read this Clause
- •12.2 BPMN Diagram Interchange (DI) Meta-model
- •12.2.1 Overview
- •12.2.2 Abstract Syntax
- •12.2.3 Classifier Descriptions
- •12.2.4 Complete BPMN DI XML Schema
- •12.3 Notational Depiction Library and Abstract Element Resolutions
- •12.3.1 Labels
- •12.3.2 BPMNShape
- •Markers for Activities
- •Tasks [BPMNShape]
- •Collapsed Sub-Processes [BPMNShape]
- •Expanded Sub-Processes [BPMNShape]
- •Collapsed Ad Hoc Sub-Processes [BPMNShape]
- •Expanded Ad Hoc Sub-Processes [BPMNShape]
- •Collapsed Transactions [BPMNShape]
- •Expanded Transactions [BPMNShape]
- •Collapsed Event Sub-Processes [BPMNShape]
- •Expanded Event Sub-Processes [BPMNShape]
- •Call Activities (Calling a Global Task) [BPMNShape]
- •Collapsed Call Activities (Calling a Process) [BPMNShape]
- •Expanded Call Activities (Calling a Process) [BPMNShape]
- •Data [BPMNShape]
- •Events [BPMNShape]
- •Gateways [BPMNShape]
- •Artifacts [BPMNShape]
- •Lanes [BPMNShape]
- •Pools [BPMNShape]
- •Choreography Tasks [BPMNShape]
- •Collapsed Sub-Choreographies [BPMNShape]
- •Expanded Sub-Choreographies [BPMNShape]
- •Call Choreographies (Calling a Global Choreography Task) [BPMNShape]
- •Collapsed Call Choreographies (Calling a Choreography) [BPMNShape]
- •Expanded Call Choreographies (Calling a Choreography) [BPMNShape]
- •Choreography Participant Bands [BPMNShape]
- •Conversations [BPMNShape]
- •12.3.3 BPMNEdge
- •Connecting Objects [BPMNEdge]
- •12.4 Example(s)
- •12.4.1 Depicting Content in a Sub-Process
- •Expanded Sub-Process
- •Expanded Sub-Process with Start and End Events on Border
- •Collapsed Sub-Process
- •12.4.2 Multiple Lanes and Nested Lanes
- •12.4.3 Vertical Collaboration
- •12.4.4 Conversation
- •12.4.5 Choreography
- •13 BPMN Execution Semantics
- •13.1 General
- •13.2 Process Instantiation and Termination
- •13.3 Activities
- •13.3.1 Sequence Flow Considerations
- •13.3.2 Activity
- •13.3.3 Task
- •13.3.4 Sub-Process/Call Activity
- •13.3.5 Ad-Hoc Sub-Process
- •Operational semantics
- •13.3.6 Loop Activity
- •13.3.7 Multiple Instances Activity
- •13.4 Gateways
- •13.4.1 Parallel Gateway (Fork and Join)
- •13.4.2 Exclusive Gateway (Exclusive Decision (data-based) and Exclusive Merge)
- •13.4.3 Inclusive Gateway (Inclusive Decision and Inclusive Merge)
- •13.4.4 Event-based Gateway (Exclusive Decision (event-based))
- •13.4.5 Complex Gateway (related to Complex Condition and Complex Merge)
- •13.5 Events
- •13.5.1 Start Events
- •13.5.2 Intermediate Events
- •13.5.3 Intermediate Boundary Events
- •13.5.4 Event Sub-Processes
- •Operational semantics
- •13.5.5 Compensation
- •Compensation Handler
- •Compensation Triggering
- •Relationship between Error Handling and Compensation
- •Operational Semantics
- •13.5.6 End Events
- •Process level end events
- •Sub-process level end events
- •14 Mapping BPMN Models to WS-BPEL
- •14.1 General
- •14.2 Basic BPMN-BPEL Mapping
- •14.2.1 Process
- •14.2.2 Activities
- •Common Activity Mappings
- •Task Mappings
- •Service Task
- •Receive Task
- •Send Task
- •Abstract Task
- •Service Package
- •Message
- •Interface and Operation
- •Conversations and Correlation
- •Sub-Process Mappings
- •Mapping of Event Sub-Processes
- •Activity Loop Mapping
- •Standard Loops
- •Dealing with LoopMaximum
- •Multi-Instance Activities
- •14.2.3 Events
- •Start Event Mappings
- •Message Start Events
- •Error Start Events
- •Compensation Start Events
- •Intermediate Event Mappings (Non-boundary)
- •Message Intermediate Events (Non-boundary)
- •Timer Intermediate Events (Non-boundary)
- •Compensation Intermediate Events (Non-boundary)
- •End Event Mappings
- •None End Events
- •Message End Events
- •Error End Events
- •Compensation End Events
- •Terminate End Events
- •Boundary Intermediate Events
- •Message Boundary Events
- •Error Boundary Events
- •Compensation Boundary Events
- •Multiple Boundary Events, and Boundary Events with Loops
- •14.2.4 Gateways and Sequence Flows
- •Exclusive (Data-based) Decision Pattern
- •Exclusive (Event-based) Decision Pattern
- •Inclusive Decision Pattern
- •Parallel Pattern
- •Sequence Pattern
- •Structured Loop Patterns
- •Handling Loops in Sequence Flows
- •14.2.5 Handling Data
- •Data Objects
- •Properties
- •Input and Output Sets
- •Data Associations
- •Expressions
- •Assignments
- •14.3 Extended BPMN-BPEL Mapping
- •14.3.1 End Events
- •14.3.2 Loop/Switch Combinations From a Gateway
- •14.3.3 Interleaved Loops
- •14.3.4 Infinite Loops
- •14.3.5 BPMN Elements that Span Multiple WSBPEL Sub-Elements
- •15 Exchange Formats
- •15.1 Interchanging Incomplete Models
- •15.2 Machine Readable Files
- •15.3.1 Document Structure
- •15.3.2 References within the BPMN XSD
- •15.5 XSLT Transformation between XSD and XMI
- •B.1 Scope
- •B.2 Architecture
- •B.3 Diagram Common
- •B.3.1 Overview
- •B.3.2 Abstract Syntax
- •B.3.3 Classifier Descriptions
- •B.4 Diagram Interchange
- •B.4.1 Overview
- •B.4.2 Abstract Syntax
- •B.4.3 Classifier Descriptions
13.4 Gateways
This sub clause describes the behavior of Gateways.
13.4.1 Parallel Gateway (Fork and Join)
X1 |
Y1 |
X m |
Yn |
Figure 13.3 – Merging and Branching Sequence Flows for a Parallel Gateway
On the one hand, the Parallel Gateway is used to synchronize multiple concurrent branches (merging behavior). On the other hand, it is used to spawn new concurrent threads on parallel branches (branching behavior).
Table 13.1 – Parallel Gateway Execution Semantic
Operational Semantics |
The Parallel Gateway is activated if there is at least one token on each |
|
incoming Sequence Flow. |
|
The Parallel Gateway consumes exactly one token from each incoming |
|
Sequence Flow and produces exactly one token at each outgoing Sequence |
|
Flow. |
|
If there are excess tokens at an incoming Sequence Flow, these tokens remain at |
|
this Sequence Flow after execution of the Gateway. |
|
|
Exception Issues |
The Parallel Gateway cannot throw any exception. |
|
|
Workflow Patterns Support |
Parallel Split (WCP-2) |
|
Synchronization (WCP-3) |
|
|
13.4.2 Exclusive Gateway (Exclusive Decision (data-based) and Exclusive Merge)
X 1 |
C o n d 1 |
Y 1 |
|
C o n d 2
Y 2
X m |
D e fa u lt |
Y 3 |
|
|
Figure 13.4 – Merging and Branching Sequence Flows for an Exclusive Gateway
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Business Process Model and Notation (BPMN), v2.0.2 |
The Exclusive Gateway has pass-through semantics for a set of incoming branches (merging behavior). Further on, each activation leads to the activation of exactly one out of the set of outgoing branches (branching behavior).
Table 13.2 – Exclusive Gateway Execution Semantics
Operational Semantics |
Each token arriving at any incoming Sequence Flows activates the |
|
gateway and is routed to exactly one of the outgoing Sequence Flows. |
|
In order to determine the outgoing Sequence Flows that receives the |
|
token, the conditions are evaluated in order. The first condition that |
|
evaluates to true determines the Sequence Flow the token is sent to. |
|
No more conditions are henceforth evaluated. |
|
If and only if none of the conditions evaluates to true, the token is passed |
|
on the default Sequence Flow. |
|
In case all conditions evaluate to false and a default flow has not been |
|
specified, an exception is thrown. |
|
|
Exception Issues |
The exclusive gateway throws an exception in case all conditions |
|
evaluate to false and a default flow has not been specified. |
|
|
Workflow Patterns Support |
Exclusive Choice (WCP-4) |
|
Simple Merge (WCP-5) |
|
Multi-Merge (WCP-8) |
|
|
13.4.3 Inclusive Gateway (Inclusive Decision and Inclusive Merge)
X 1 |
C o n d 1 |
Y 1 |
|
C o n d 2
Y 2
X m |
D e f a u lt |
Y 3 |
|
|
Figure 13.5 – Merging and Branching Sequence Flows for an Inclusive Gateway
The Inclusive Gateway synchronizes a certain subset of branches out of the set of concurrent incoming branches (merging behavior). Further on, each firing leads to the creation of threads on a certain subset out of the set of outgoing branches (branching behavior).
Business Process Model and Notation (BPMN), v2.0.2 |
435 |
Table 13.3 – Inclusive Gateway Execution Semantics
Operational Semantics |
The Inclusive Gateway is activated if |
|
• At least one incoming Sequence Flow has at least one token and |
|
• For every directed path formed by sequence flow that |
|
- starts with a Sequence Flow f of the diagram that has a token, |
|
- ends with an incoming Sequence Flow of the inclusive gateway |
|
that has no token, and |
|
- does not visit the Inclusive Gateway. |
|
• There is also a directed path formed by Sequence Flow that |
|
- starts with f, |
|
- ends with an incoming Sequence Flow of the inclusive gateway |
|
that has a token, and |
|
- does not visit the Inclusive Gateway. |
|
Upon execution, a token is consumed from each incoming Sequence Flow that |
|
has a token. A token will be produced on some of the outgoing Sequence |
|
Flows. |
|
In order to determine the outgoing Sequence Flows that receive a token, all |
|
conditions on the outgoing Sequence Flows are evaluated. The evaluation |
|
does not have to respect a certain order. |
|
For every condition which evaluates to true, a token MUST be passed on the |
|
respective Sequence Flow. |
|
If and only if none of the conditions evaluates to true, the token is passed on the |
|
default Sequence Flow. |
|
In case all conditions evaluate to false and a default flow has not been specified, |
|
the Inclusive Gateway throws an exception. |
|
|
Exception Issues |
The inclusive gateway throws an exception in case all conditions evaluate |
|
to false and a default flow has not been specified. |
|
|
Workflow Patterns Support |
Multi-Choice (WCP-6) |
|
Structured Synchronizing Merge (WCP-7) |
|
Acyclic Synchronizing Merge (WCP-37) |
|
General Synchronizing Merge (WCP-38) |
|
|
436 |
Business Process Model and Notation (BPMN), v2.0.2 |
13.4.4 Event-based Gateway (Exclusive Decision (event-based))
X1 |
Y1 |
Xm |
Yn |
Figure 13.6 – Merging and branching Sequence Flows for an Event-Based Gateway
The Event-Based Gateway has pass-through semantics for a set of incoming branches (merging behavior). Exactly one of the outgoing branches is activated afterwards (branching behavior), depending on which of Events of the Gateway configuration is first triggered. The choice of the branch to be taken is deferred until one of the subsequent Tasks or Events completes. The first to complete causes all other branches to be withdrawn.
When used at the Process start as a Parallel Event Gateway, only message-based triggers are allowed. The Message triggers that are part of the Gateway configuration MUST be part of a Conversation with the same correlation information. After the first trigger instantiates the Process, the remaining Message triggers will be a part of the Process instance that is already active (rather than creating new Process instances).
Table 13.4 – Event-Based Gateway Execution Semantics
Exception Issues |
The event-based gateway cannot throw any exception. |
|
|
Workflow Patterns Support |
Deferred Choice (WCP-16) |
|
|
13.4.5 Complex Gateway (related to Complex Condition and Complex Merge)
x1 |
C o nd 1 |
y 1 |
|
C on dn
y n
x m |
D efa ult |
|
Figure 13.7 – Merging and branching Sequence Flows for a Complex Gateway
The Complex Gateway facilitates the specification of complex synchronization behavior, in particular race situations. The diverging behavior is similar to the Inclusive Gateway. Each incoming gate of the Complex Gateway has an attribute activationCount, which can be used in an Expression as an integer-valued variable. This variable represents the number of tokens that are currently on the respective incoming Sequence Flows. The Complex Gateway has an attribute activationExpression. An activationExpression is a boolean Expression that refers to data and to the activationCount of incoming gates. For example, an activationExpression could be x1+x2+…+xm >= 3 stating that it needs 3 out of the m incoming gates to have a token in order to proceed. To
Business Process Model and Notation (BPMN), v2.0.2 |
437 |
prevent undesirable oscillation of activation of the Complex Gateway, ActivationCount variables should only be used in subexpressions of the form expr >= const where expr is an arithmetic Expression that uses only addition and const is an Expression whose evaluation remains constant during execution of the Process.
Each outgoing Sequence Flow of the Complex Gateway has a boolean condition that is evaluated to determine whether that Sequence Flow receives a token during the execution of the Gateway. Such a condition MAY refer to internal state of the Complex Gateway. There are two states: waiting for start (represented by the runtime attribute waitingForStart = true) and waiting for reset (waitingForStart=false).
Table 13.5 – Semantics of the Complex Gateway
Operational Semantics |
The Complex Gateway is in one of the two states: waiting for start or waiting |
|
for reset, initially it is in waiting for start. If it is waiting for start, then it waits for |
|
the activationExpression to become true. The activationExpres- |
|
sion is not evaluated before there is at least one token on some incoming |
|
Sequence Flow. When it becomes true, a token is consumed from each |
|
incoming Sequence Flow that has a token. To determine which outgoing |
|
Sequence Flow receive a token, all conditions on the outgoing Sequence |
|
Flows are evaluated (in any order). Those and only those that evaluate to true |
|
receive a token. If no condition evaluates to true, and only then, the default |
|
Sequence Flow receives a token. If no default flow is specified an exception |
|
is thrown. The Gateway changes its state to waiting for reset.The Gateway |
|
remembers from which of the incoming Sequence Flows it consumed tokens in the |
|
first phase. |
|
When waiting for reset, the Gateway waits for a token on each of those incoming |
|
Sequence Flows from which it has not yet received a token in the first phase unless |
|
such a token is not expected according to the join behavior of an inclusive |
|
Gateway. |
More precisely, the Gateway being waiting for reset, resets when for every directed path formed by sequence flow that
-starts with a Sequence Flow f of the diagram that has a token,
-ends with an incoming Sequence Flow of the Complex Gateway that has no token and has not consumed a token in the first phase, and that
-does not visit the Complex Gateway.
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