OCEB2F 05 Business Process Modeling Concepts

Module 5. Business Process Modeling Concepts⌘

Business Process Model and Notation (BPMN)⌘

• The primary goal of BPMN is to provide a notation that is readily understandable by all business users, from the business analysts to the technical developers, and finally to the business people.
• BPMN is a standardized business process modelling bridge for the gap between the business process design and process implementation.
• A vision of BPMN is that it can visually model business activities that become machine executable
• BPMN 2.0 specification - http://www.omg.org/spec/BPMN/2.0/

Business Process⌘

BPMN 2.0 Spec:

A Process describes a sequence or flow of Activities 
in an organization with the objective of carrying out work.

Process Logic⌘

by Bruce Silver

• Process Logic (Process Model) is a complete map of all the paths from the triggering event to any defined end state.
• Process Model is more than documentation of one instance of the process.
• Process logic is usually hidden.

BPMN 2.0 XML⌘

• BPMN 2.0 file is an executable XML representation of a business process

<?xml version="1.0" encoding="UTF-8"?> 
<definitions id="Definition" ... >

  <process processType="Private" isExecutable="true" id="com.sample.bpmn.hello" 
     name="Hello World" >

    <!-- nodes -->
    <scriptTask id="_2" name="Hello" >
      <script>System.out.println("Hello World");</script>
    </scriptTask>
    <startEvent id="_1" />
    <endEvent id="_3" >
        <terminateEventDefinition/>
    </endEvent>

    <!-- connections -->
    <sequenceFlow id="_1-_2" sourceRef="_1" targetRef="_2" />
    <sequenceFlow id="_2-_3" sourceRef="_2" targetRef="_3" />

  </process>

BPMN 2.0 XML⌘

  <bpmndi:BPMNDiagram>
    <bpmndi:BPMNPlane bpmnElement="com.sample.bpmn.hello" >
      <bpmndi:BPMNShape bpmnElement="_2" >
        <dc:Bounds x="96" y="16" width="80" height="48" />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape bpmnElement="_1" >
        <dc:Bounds x="30" y="22" width="36" height="36" />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape bpmnElement="_3" >
        <dc:Bounds x="210" y="22" width="36" height="36" />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNEdge bpmnElement="_1-_2" >
        <di:waypoint x="66" y="40" />
        <di:waypoint x="96" y="40" />
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge bpmnElement="_2-_3" >
        <di:waypoint x="176" y="40" />
        <di:waypoint x="210" y="40" />
      </bpmndi:BPMNEdge>
    </bpmndi:BPMNPlane>
  </bpmndi:BPMNDiagram>

</definitions>

BPMN Basics⌘

BPMN Activity Basics⌘

• Activity denotes work that is performed within a business process
• Activity can be:
  • Task - the finest level of the process step. Cannot be broken down to a finer level.
  • Subprocess - compound activity (flow of other activities)
    • Collapsed
    • Expanded

Sub-process Rules⌘

• Pools or Lanes can't be used inside a sub-process
• A Sub-process can have only None Start Events

• A sequence flow can't cross a sub-process boundary

Sequence Flow⌘

A Sequence Flow is used to show the order that Activities will be performed in a Process.

Token ⌘

• Token traverses the Sequence Flows and passes through the elements in the Process
• A token is a theoretical concept that is used as an aid to define the behavior of a Process that is being performed
• The behavior of Process elements can be defined by describing how they interact with a token as it “traverses” the structure of the Process.
• A token does NOT traverse a Message Flow

Sequence Flow Splitting⌘

• Conditional flow - sequence flow with a condition that is evaluated to determine whether or not the sequence flow will be used
• Default flow - (with slash marker) used only if all the other outgoing conditional flows are not true

Gateways⌘

Gateways are used to control splitting and merging of sequence flows. do not represent ‘work’ being done are considered to have zero effect on the operational measures of the process (cost, time, etc.). two types of gateways: converge and diverge are optional

Exclusive⌘

        

XOR Gateway

• A diverging Exclusive Gateway (Decision) is used to create alternative paths within a Process flow
• Only one of the paths can be taken, this means the gateway is exclusive
• A Decision can be thought of as a question that is asked at a particular point in the Process
• The question has a defined set of alternative answers
• Each answer is associated with a condition Expression that is associated with a Gateway’s outgoing Sequence Flows

Exclusive Gateway Example⌘

Merging (exclusive)⌘

Parallel Gateway ⌘

AND Gateway

• A Parallel Gateway is used to create or synchronize (combine) parallel flows
• A Parallel Gateway creates parallel paths without checking any conditions; each outgoing Sequence Flow receives a token upon execution of this Gateway
• For incoming flows, the Parallel Gateway will wait for all incoming flows before triggering the flow through its outgoing Sequence Flows

Parallel Gateway Example 1⌘

Parallel Gateway Example 2⌘

Quiz, what will happen?⌘

Inclusive Gateway ⌘

OR Gateway

• A diverging Inclusive Gateway (Inclusive Decision) can be used to create alternative but also parallel paths within a Process flow
• Unlike the Exclusive Gateway, all condition Expressions are evaluated
• The true evaluation of one condition Expression does not exclude the evaluation of other condition Expressions
• All Sequence Flows with a true evaluation will be traversed by a token
• Since each path is considered to be independent, all combinations of the paths MAY be taken, from zero to all
• However, it should be designed so that at least one path is taken.

Inclusive Gateway Example 1⌘

Inclusive Gateway Example 2⌘

Event Basics⌘

An Event is something that “happens” during the course of a Process.

• Events affect the flow of the Process and usually have a cause or an impact. The term “event” is general enough to cover many things in a Process.
• The start of an Activity, the end of an Activity, the change of state of a document, a Message that arrives, etc., all could be considered Events

Types of events⌘

• Start Events - indicate where a particular Process will start (generates a token)
• Intermediate Events - indicate where something happens (an Event) somewhere between the start and end of a Process
  • Boundary Intermediate Events - attached to the boundary of an Activity
• End Events - indicate where a Process will end (consumes a token - marks the end of a path)

Start and End⌘

• A Start Event is OPTIONAL
• a Process level — a top-level Process or an expanded Sub-Process — MAY have a Start Event:
  • If a Process is complex or the starting conditions are not obvious, then it is RECOMMENDED that a Start Event be used
• If there is an End Event, then there MUST be at least one Start Event.
• If there is a Start Event, then there MUST be at least one End Event.
• End events cannot (by definition) accept outgoing sequence flow.

Processes without start or end event⌘

• If the Start Event is used, then there MUST NOT be other flow elements that do not have incoming Sequence Flow — all other Flow Objects MUST be a target of at least one Sequence Flow
• If the Start Event is not used, then all Flow Objects that do not have an incoming Sequence Flow (i.e., are not a target of a Sequence Flow) SHALL be instantiated when the Process is instantiated.
• If there is no End Event: every flow object without any outgoing flow means the end of the path

None Events⌘

• None Event does not have a defined trigger or result.
• The Event MUST be displayed without a marker
• None Start Event starts the process and generates new token
• None End Event ends a particular flow and consumes the token

Events Example 1⌘

Events Example 2⌘

No Events Example⌘

Messages⌘

• There are three types of message events
  • Start
  • Intermediate
  • End
• Intermediate event can send or wait for a message (receive a message)

Messages example⌘

Messages and Sequences⌘

• Sequence Flow
  • Solid line with an arrow on one end
  • depict when one activity has started and another has ended.
  • defines the order in which actives are performed for any given process participant
  • Never occurs between participants
• Message flow
  • Defines the flow of information and messages between participants within a process
  • Messages NEVER occur within the same participant
  • A token does NOT traverse a Message Flow

Sequence and Message flow⌘

Pools and Lanes⌘

• Pool = Participant
  • The pool shape contains the elements of a process flow performed by the process participant
  • The pool shape represents a participant
  • The pool shape is optional

Pools and Lanes⌘

• Lane
  • A lane in BPMN is an optional subdivision of a pool, but can be used without a pool
  • Graphically separates areas of the process diagram for more visibility and understanding
  • Documentation only, doesn't execute
  • Text can be in any direction
  • The meaning of the Lanes is up to the modeler.
  • Lanes are often used for such things as internal roles (e.g., Manager, Associate), systems (e.g., an enterprise application), an internal department (e.g., shipping, finance),

Black/White Box Pools⌘

Pool may have no internal details - "black box pool" or may be shown as a "white box pool" with all details.

Event-Based Exclusive Gateway⌘

• The Event-Based Gateway represents a branching point in the Process where the alternative paths that follow the Gateway are based on Events that occur
• This is opposed to the evaluation of Expressions using Process data (as with an Exclusive or Inclusive Gateway which are Data Based)
• A specific Event, usually the receipt of a Message, determines the path that will be taken
• Basically, the decision is made by another Participant, based on data that is not visible to Process, thus, requiring the use of the Event-Based Gateway.

Example⌘

• A company is waiting for a response from a customer they will perform one set of Activities if the customer responds “Yes” and another set of Activities if the customer responds “No.”
• The customer’s response determines which path is taken
• The identity of the Message determines which path is taken
• That is, the “Yes” Message and the “No” Message are different Messages

Example⌘

• The receipt of the Message can be modeled with an Intermediate Event with a Message trigger or a Receive Task
• In addition to Messages, other triggers for Intermediate Events can be used, such as Timers

or

Artifacts⌘

• Artifacts
  • Text annotation
  • Groups
• Artifacts have no impact on execution they extend the documentation
• Text objects can be connected to any object with an Association

Group⌘

• Provides a visual mechanism to group elements of a diagram informally.
• Group can be used for documentation or analysis purposes.
• Groups do not affect the flow of the Process.

Text Annotation ⌘

• Is a mechanism for a modeler to provide additional information for the reader of a BPMN Diagram
• The Text Annotation object can be connected to a specific object on the Diagram with an Association
• Does not affect the flow of the Process

Association⌘

• Association lines are dotted connections to objects
  • Association appears as a dotted line and optional arrow
  • A directional Association is often used with Data Objects to show that a Data Object is either an input to or an output from an activity

Data Objects⌘

• The primary construct for modeling data within the Process flow.
• Represented by the rectangle and the folded corner
• Typically attached to activities and flows, but they can be associated with: tasks, gateways, events, sequence lines or message lines
• Data Associations are used to move data between Data Objects.
• Tokens do not flow along a Data Association.

Module 5. Questions⌘

• What types of events are there in BPMN?
• What types of gateways are there in BPMN?
• What is an artifact?
• What is the difference between Pool and Participant?
• What is the difference between Pool and Lane?