Architecture

Components

Simulation Engine consists of following components:

• simulation-api - interfaces that will be exposed to the client or should be implemented by the client
• simulation-engine - core implementation responsible for preparing simulation and execution of simulation
• simulation-signavio-plugin - plugin to Signavio modeler to be able to launch simulation directly from the modeler
• simulation-engine-adapter-activiti - Activiti adapter to be able to utilize Activiti Engine
• simulation-engine-adapter-jbpm4 - JBPM4 adapter to be able to utilize JBPM4 Engine (process diagram format is JPDL)

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Simulation Engine

Simulation engine will run every simulation is stages:

• preparation stage
  • load process diagram
  • resolve alternative paths
  • calculate alternative path probability
  • calculate number of instances for alternative path
  • generate random start times
• simulation stage
  • create instance for every alternative path
  • invoke registered simulation features for every activity (including sequence flows or transitions if you like)
  • record every activity statistic
  • record every path statistic
• generation stage
  • generate report based on recorded statistics

Something that is rather not clear is what is Simulation Feature. Simulation Feature represents a unit of work that could be applied to simulation on one of four defined phases:

• PATH - it will be invoked on every alternative path, only once
• PATH_INSTANCE - it will be invoked for every instances of given alternative path during simulation stage
• ELEMENT - it will be invoked on every element (activity or sequence flow), only once
• ELEMENT_INSTANCE - it will be invoked for every instance of an element (activity or sequence flow) during simulation stage

An example of such Simulation Feature is - Activity execution time - that is responsible for calculating execution and wait time for an activity.