Dynamic Simulation with JavaScript

Analyzer Script Input

If you enter JavaScript code into the Execution Analyzer window 'Input' field, this code will be injected into the Simulation and executed before the Simulation starts. This is useful for establishing COM variables, global counters, functions and other initialization.

Transition and Control Flow Guards

This is the workhorse of the Simulation functionality. As Enterprise Architect evaluates possible paths forward at each node in a Simulation, it tests the Guards on outgoing transitions and control flows and will only move forward if there is a single true path to follow - otherwise the Simulation is considered 'blocked' and manual intervention is required. You must use the '==' operator to test for equality.

Element Behavior

Entry and Exit behavior can be defined for States. Such code will execute at the appropriate time and is useful for updating Simulation variables and making other assignments.

You can also simulate the behavior of Classes via their Object Instances, and Activities in your model.

Using COM

One very important feature of the implementation of JavaScript in Enterprise Architect's Simulator is that it supports the creation of COM objects. This provides the ability to connect the running Simulation with almost any other local or remote process and either influence the Simulation based on external data, or potentially change data or behavior in the external world based on the current Simulation state (for example, update a mechanical model or software Simulation external to Enterprise Architect). The syntax for creating COM objects is shown here:

     this.name="Odd Even";

     var logger = new COMObject("MySim.Logger");

     logger.Show();

     logger.Log("Simulation started");

Using Solvers

Anywhere in Enterprise Architect that has JavaScript code, such as in Dynamic Simulation, you can now use a JavaScript construct called 'Solver' (the Solver Class) to integrate with external tools and have direct use of the functionality within each tool to simply and intuitively perform complex math and charting functions. The calls help you to interchange variables between the built in JavaScript engine and each environment easily. Two Math Libraries that are supported are MATLAB and Octave.

To use the Solver Class, you need to have a knowledge of the functions available in your preferred Math Library and the parameters they use, as described in the product documentation.

Being part of the JavaScript engine, these Solver Classes are also immediately accessible to Add-In writers creating model based JavaScript Add-Ins.

See the Octave Solver, MATLAB Solver and Solvers Help topics for further details.

Signalled Actions

It is possible to raise a signalled event (trigger) directly using JavaScript. The BroadcastSignal() command is used to raise a named trigger that could influence the current state of a Simulation. For example, this fragment raises the signal (trigger) named "CancelPressed".

     BroadcastSignal("CancelPressed");

Note that a trigger named CancelPressed must exist within the current Simulation environment and must uniquely have that name.

You can also call the signal using its GUID. For example:

     BroadcastSignal("{996EAF52-6843-41f7-8966-BCAA0ABEC41F}");

IS_IN()

The IS_IN(state) operator returns True if the current Simulation has an active state in any thread matching the passed in name. For example, to conditionally control execution it is possible to write code such as this:

     if (IS_IN("WaitingForInput"))

     BroadcastSignal("CancelPressed")

Note that the name must be unique within all contexts.

Trace()

The Trace(statement) method allows you to print out Trace statements at any arbitrary point in your Simulation. This is an excellent means of supplementing the Simulation log with additional output information during execution.

The JavaScript Simulation will truncate strings that exceed the defined maximum length of the Trace message.