History: GalaxiaConcepts

Introduction and concepts
Galaxia is an “activity based” workflow. Workflow processes are
implemented as a set of activities that must be completed to achieve some result.
In Galaxia activities are represented as PHP scripts. Galaxia provides 3 big
modules called: “Process Manager”, “Process Controlle r” and “Workflow”.

Definitions

Process: A process is defined as a set of activities that must be done to achieve
some goal. Business circuits are mapped to processes to automate them.
Process activities are connected using transitions defining what has to be done
after each activity is completed.

Activity: An activity is something that has to be done as a part of a process. In
Galaxia activities are mapped to PHP scripts so an activity can do anything that
can be done from a PHP script.

Role: Activities are asocited to roles defining who can perform activities. Roles
are defined at a per-process level.

Instance: An instance is a process being executed. An instance is created when a
process is started and the instance passes through the process activities until the
process is terminated.

Workitem: When an activity is completed a workitem is added to the instance.
Workitems thus represent completed activities.

Activity types
Galaxia defines seven basic activity types that can be used to design a
process:

Galaxia activity types:

• Start
• End
• Activity
• Switch
• Split
• Join
• Standalone

Start activities are represented using a circle. Every process must
have at least one start activity. Start is the only activity type that
can be executed without the presence of an inta nce in the activity
because instances are created when a start activity is executed.
Processes with many start activities are very strange but possible
in Galaxia. No transitions can lead to a start activity and only one outgoing
transition is allowed per each start activity.

The end activity represents the end of a process. When an
instance reaches the end activity the process is considered
completed. Process must have exactly one end activity. This
doesn’t mean that processes can’t end in different ways since the
end activity represents only that the process ends, how the process
ends depends on the activities visited before the end activity. The end activity is
represented in Galaxia using a double circle. The end activity can have many
inbound transitions. Outbound transitions are not allowed.

Normal activities don’t have any special meaning so they are used
to represent things that should be done as a part of a process. A
rectangle is used to represent these activities. Normal activities can
receive many inbound transitions but can only have one outbound
transition.

A switch activity represents a point of decision in a process.
Instances reaching a switch activity are evluated and depending
on some conditions the instance can be routed to different
activities. Then switch activities can have many inbound
transitions and many outbound transitions. Switch activities are
represented using a diamond.

Sometimes two or more activities in a process can be done independantely in paralell. A split activity is used to split the an instance routing the same instance to many activities. Then it is true that an instance can be in many activities at the same time.
Split activities represent subflows in a workflow. A split activity can receive many inbound transitions and can have many outbound transitions. Split activities are presented by a triangle.

A join activity is used to re-group instances splitted from a split activity. When an instance reaches a join activity the engine verifies if the instance is present also in some other activity if so the instance must wait in the join activity until all the copies of the instance reach the join activity. Once all the instance copies reach the join activity the instance can be directed to the next activity. Join activities can have many inbound transitions (more than one is expected) and can only have one outbound activities. Jion activities are represented using an inverted triangle.

Standalone activities are represented by hexagons. A standalone activity is not part of the normal flow of the process so they are not related to process instances. A standalone activity can be executed any time a user with the right permissions want. This activities are ideal for data management related to the process, listings, adding items, removing items, etc. It’s true that many processes can be designed as a set of standalone activities if there’s no order relationship between the different activities in the process. Other processes consist of a main process flow and a set of auxiliar standalone activities. Standalone activities can’t have inbound or outbound transitions.