Fountainedge Workflow Engine v1.0.8

View Source Fountainedge.Node (Fountainedge Workflow Engine v1.0.8)

A graph node (also known as a vertex.)

Graphviz is used for presentation and ranking of graph nodes. See Graphvix.Graph.add_vertex/3.

forking-and-synchronisation

 Forking and Synchronisation

To create a parallel process, create a node of type :fork.

The fork node must be associated with a node of type :join.

The forking node will create tokens for each out edge. The join node will synchronise the parallel processes by preventing the workflow from proceeding beyond until all of these tokens are collected.

Here is an example where a fork creates three tokens for each separate branch.

Nodes:

[
  ...
  %Node{id: 5, type: :fork, join: 9},
  %Node{id: 6, label: "Parallel 1"},
  %Node{id: 7, label: "Parallel 2"},
  %Node{id: 8, label: "Parallel 3"},
  %Node{id: 9, type: :join},
  ...
]

Edges:

[
  ...
  %Edge{id: 5, next: 6},
  %Edge{id: 5, next: 7},
  %Edge{id: 5, next: 8},
  %Edge{id: 6, next: 9},
  %Edge{id: 7, next: 9},
  %Edge{id: 8, next: 9},
  ...
]

Link to this section Summary

Types

t()

Node structure.

Functions

find(nodes, id)

Find a matching node in a list (used internally.)

Link to this section Types

Link to this type

t()

View Source 
@type t() :: %Fountainedge.Node{
  attributes: list(),
  id: integer(),
  join: integer() | nil,
  label: String.t() | nil,
  rank: integer() | nil,
  type: :normal | :initial | :final | :fork | :join
}

Node structure.

  • :id - Identifier of the node.
  • :type - Node type, one of:
  • :normal - Normal node (default.)
    • :initial - Start node.
    • :final - End node.
    • :fork - Fork into a parallel process. The joining node must be specified.
    • :join - Synchronise (join) a parallel process. The workflow will stop here until all tokens (Fountainedge.Token) generated by the fork are collected.
  • :join - Used when forking with type :fork. Specifies the node identifier of the associated joining node where the parallel workflow will eventually synchronise. The joining node must be of type :join.
  • :label - Optional label.
  • :rank - Hierarchical rank of the node. The rank is used for determining backward and forward directions from the initial to final node when navigating through the workflow. The rankings are defined by calling Fountainedge.Graph.rank/2 on the schema.
  • :attributes Optional list of node attributes passed to Graphvix.Graph.add_vertex/3.

Link to this section Functions

Link to this function

find(nodes, id)

View Source 
@spec find([t()], integer()) :: t() | nil

Find a matching node in a list (used internally.)