Business Process Model and Notation

What is BPMN?

BPMN is flow-chart based notation for defining Business Processes BPMN is an agreement between multiple modelling tools vendors, who had their own notations, to use a single notation for the benefit of end-user understand and training.

What is Process Modelling?

The capturing of an ordered sequence of business activities and supporting information.Business processes describe how a business pursues its objectives.There are different levels of process modelling:
Process Maps – simple flow charts of the activities
Process Descriptions – flow charts extended with additional information, but not enough to fully define actual performance.
Process Models – flow charts extended with enough information so that the process can be analyzed, simulated, and/or executed

BPMN Process Types

The BPMN core elements, which include those defined in the Infrastructure, Foundation, Common, and Service packages
Process diagrams, which include the elements defined in the Process, Activities, Data, and Human Interaction packages.
Collaboration diagrams, which include Pools and Message Flow
Conversation diagrams, which include Pools, Conversations, and Conversation Links.

Private (Internal) Business Processes:

Private Business Processes are those internal to a specific organization.If a swim lanes-like notation is used (e.g., a Collaboration, see below) then a private Business Process will be contained within a single Pool. The Process flow is therefore contained within the Pool and cannot cross the boundaries of the Pool. The flow of Messages can cross the Pool boundary to show the interactions that exist between separate private Business Processes.

Public Processes

A public Process represents the interactions between a private Business Process and another Process or Participant Only those Activities that are used to communicate to the other Participant(s) are included in the public Process. All other “internal” Activities of the private Business Process are not shown in the public Process. Public Processes can be modelled separately or within a Collaboration to show the flow of Messages between the public Process Activities and other Participants.

Collaborations

Collaboration depicts the interactions between two or more business entities. Collaboration usually contains two or more Pools, representing the Participants in the Collaboration. The Message exchange between the Participants is shown by a Message Flow that connects two Pools (or the objects within the Pools). The Messages associated with the Message Flows can also be shown.All combinations of Pools, Processes, and Choreography are allowed in Collaboration.

Choreographies

A self-contained Choreography (no Pools or Orchestration) is a definition of the expected behaviour, basically a procedural contract, between interacting Participants. While a normal Process exists within a Pool, Choreography exists between Pools (or Participants).
The Choreography looks similar to a private Business Process since it consists of a network of Activities, Events, and Gateways. However, Choreography is different in that the Activities are interactions that represent a set of Message exchanges, which involves two (2) or more Participants.

Conversations

The Conversation diagram is a particular usage of and an informal description of a Collaboration diagram. However, the Pools of a Conversation usually do not contain a Process and Choreography is usually not placed in between the Pools of a Conversation diagram.
A Conversation is the logical relation of Message exchanges. The logical relation, in practice, often concerns a business object(s) of interest, e.g., “Order,” “Shipment and Delivery,” or “Invoice.”

Diagram Point of View

Since a BPMN Diagram MAY depict the Processes of different Participants, each Participant could view the Diagram differently.

Understanding the Behaviour of Diagrams:

Sequence Flows are used within a Process.A Start Event generates a token that MUST eventually be consumed at an End Event (which MAY be implicit if not graphically displayed). The path of tokens should be traceable through the network of Sequence Flows, Gateways, and Activities within a Process.

Note – A token does not traverse a Message Flow since it is a Message that is passed down a Message Flow. Message Flow is used to communicate between the pools.

BPMN Elements

The five basic categories of elements are:
• Flow Objects
• Data
• Connecting Objects
• Swim lanes
• Artifacts

Flow Objects:

Main graphical elements to define the behaviour of a Business Process. There are three Flow Objects:
• Events
• Activities
• Gateways

Data is represented with the four elements:

• Data Objects
• Data Inputs
• Data Outputs
• Data Stores

Connecting Objects

There are four ways of connecting the Flow Objects to each other or other information:
• Sequence Flows
• Message Flows
• Associations
• Data Associations

Swim lanes

There are two ways of grouping the primary modelling elements through “Swim lanes:”
• Pools
• Lanes

Artifacts:

Artifacts are used to provide additional information about the Process. There are two standardized Artifacts, but modellers or modelling tools are free to add as many Artifacts as necessary. There could be additional BPMN efforts to standardize a larger set of Artifacts for general use or for vertical markets.
• Group
• Text Annotation

Sample BPMN Diagram

Development Methodology