Model 4b - Transporting Process Variables via Messages

Goals of this lesson

Learn how to transport data (e. g. variables) between pools by using message flows

How-to

The BPMN allows transportation of explicit data by messages. We will now transfer a variable called var1 from the upper pool to the lower pool by using the message flow between the activities "Send Data" and "Receive Data".

Figure 1. Model 4b - Transporting Process Variables via Messages / IYOPRO-Link

Approach

Select the activity "Initialise Data" and define a variable called var1 with the value 1 in the expression property.
Now click the message flow.
- You will notice that it also contains an Expression property.
- Click the Edit button
- Enter the variable’s name var1 to make the message flow transport this specific variable
Since the lower pool now also possesses the variable var1, we will use it for the decision making at the branching exclusive gateway:
- Upper edge condition:
  var1==1
- Lower edge condition:
  var1==2

After simulating the model, you will notice that the activity "Evaluate to 2" has never been executed.

Report

See below for the run configuration, which we set up to receive the report statistics from below.

Please refer to the section Experiment Results for more information on the report specific data.

Run configuration

Stochastic Seed: 12345
Simulation start date: 1/1/2014 12:00:00 a.m.
Simulation stop time: 240
Simulation stop time unit: Hours

Report statistics

This report shows you that we really transported the variable var1 to the bottom pool
The activity details from Figure 2 show that there are no statistics for activity "Evaluate to 2"
- The table’s line says insufficient data for activity "Evaluate to 2"
- This happens, when the element (activity) is never reached by any process instance

Figure 2. The report’s activity details