Execution Engine

Execution Plan

For a client of the ExecutionEngine to be able to formally describe the plan that he wants to execute, the constructs offered by the Execution Plan are used. These constructs have the following main pillars.

• Configuration

  Every plan is potentially one execution unit for the execution engine. Each plan while executing can request different parametrization.

• Variables

  Tha variables defined in a plan are the common data placeholders through which the elements of the plan exchange data.

  • Data Types

    Each variable is typed and this type describes the different characteristics of the data exchanged.

  • Parameters

    Each variable is accessed through defined parameters. Parameters are distinguished by their direction and processing.

    • Filters

      Each parameter can provide either direct access to its underlying data or perform a number of elaborate filtering tasks before retrieving or storing data to its underlying Parameter and Data Type

• Execution Tree

  The plan hierarchy is composed of a number of elements that control the flow and the actions of the plan

Execution Events

Every plan created and executed, follows a life cycle which in every point is updated and reported to the client through the use of events. These events follow the Observer / Observable pattern and the defined events that are emitted during the execution life cycle are:

• Execution Started

  Event emitted when the execution is initiated

• Execution Completed

  Event emitted when the execution is completed either successfully or not

• Execution Paused

  Event emitted when the execution is paused by the client

• Execution Resumed

  Event emitted when the execution is resumed after being paused by the client

• Execution Canceled

  Event emitted when the execution is canceled by the client

• Progress Report

  Event emitted from internal Plan Elements reporting on the progress of their execution

• External Progress Report

  Event emitted from external invokable which has been invoked by one of Java Object and Web Service reporting on the progress of their execution. This is only feasible if the invoked Java object or Web Service is declared and implemented to use an Execution Context.

• Performance Report

  Event emitted from internal Plan Elements reporting timing andf performance statistics on their operation