YAWL FAQ

This page has some Frequently Asked Questions and Answers for the YAWL system used in the BPMS assignment.

Installation

Download an install Yawl from here. We tested version 3.0.1 from 12 Aug 2015.


How can I use the YAWL editor?

Use the YAWL User manual which can be found in your YAWL installation directory or via the Windows Start menu → YAWL → User Manual; there's a nice Getting Started with YAWL chapter.


How do I execute tasks in YAWL?

To start executing tasks you have to define roles and create at least one user as in the images below:

Role Creation User Creation


Can I get examples on using data perspective in YAWL?

See this file for examples on data perspective. Please note that the interface of the Editor has changed, but not this syntax.


Update Parameter Mappings in the yawl editor takes too much time or hangs

Scenario: This is mostly observed when you have the “Verify on Export” enabled and when you have a decently large model. If you are updating the parameter mappings of the tasks in this model to just a few of the tasks and try to save the specification, then you get an impression as if the YAWL editor is hung. This is because of the fact that you have enabled the “Verify on Export” feature. Since not all task's parameter mappings have been done and due to dependencies between tasks, it takes a lot of time to do the verification.

Solution: Do the parameter mappings for all the tasks before you click Ctrl-S or disable the “Verify on Export” feature when saving the specification.

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I have a problem with port 8080 when running yawl engine. The port 8080 is being used by other services. How do I change my port for YAWL engine?

In order to change the port of YAWL engine, go to the following directory of YAWL installation on your computer: <YAWL_HOME>/engine/apache-tomcat-*/conf where <YAWL_HOME> is the parent directory of your YAWL installation. Edit server.xml file in the conf directory and change the port number in <Connector port=“8080” protocol=“HTTP/1.1/”….>; to a port that is unused on your computer (for e.g., 8089). Save the changes and then invoke your YAWL engine. You can access the YAWL engine by typing in http://localhost:<NEWPORT>/resourceService.

As an alternative, you can find out which process is currently using port 8080 and terminate it. If you are using Windows, click on Start → All Programs → Accessories→ Command Prompt. Run the command netstat -aon | find /i “listening” and search in the second column for a row of type <ip address>:8080. The last row is the pid of the process. If everything goes well, you should see something like this (the 7th process is using the port 8080 and has the pid 5656):

NetStat screen

Next open Task Manager, select the menu view and in the dialog box check the pid(process identifier) field. Afterwards, search for the the process with the pid you found earlier and select terminate.


YAWL makes all my tasks and places very large?

This is due to the language settings in the .YAWL file. Open the file in a text editor (e.g., notepad++), and change “<locale language=“nl” country=“NL” />” to “<locale language=“en” country=“GB” />” in case “.” are used for decimal separator.


YAWL installation fails, what can I do?

This means that you have installed another application using tomcat - for example you installed VMWare Server before YAWL. Uninstall the other application and then try to install YAWL again. Or try to find a solution in the YAWL documentation,


YAWL does not start

If the control panel of YAWL shows, but after clicking 'Start' nothing happens, try one of the following:


How do I use the YAWL engine in a distributed manner?

First make sure that you have started the YAWL engine on your computer. Find your computer name right click My Computer, click Properties and then Computer Name tab. Copy the value from Full computer name field Now in order to access the YAWL engine from any other computer you have to use the link: http://pcwin___.campus.tue.nl:8080/resourceService


My TimeOut fires but then no tasks are enabled and the case is running

In the YAWL editor open the task decomposition of the timeout task and check “Automated” in the external interaction part. For the demonstration, we suggest to use a dummy task to simulate timeout.


I have an OR construction and the YAWL analysis reports it is unsound.

Check if in between the OR-split and OR-join you have an XOR-split in a task and a XOR-join via a place, or vice-versa. E.g. try to use an XOR-join if you do a XOR-split and a place-merge if you do a deferred choice split.


I've created a subprocess in the YAWL-Editor and now I'm getting a general error.

There seems to be a problem that in some cases when creating a subprocess task, the new subprocess is not added properly to the model. The following procedure avoids errors.

  1. Create the subprocess task.
  2. Go to the new page of the subprocess but don't change anything on that page.
  3. Save the model and close it.
  4. Open the model again. Now you can go to the page of the subprocess and edit it.

Other Resources

If you need help, you might also try the following resources:

  • The YAWL User manual which can be found in your YAWL installation directory or via the Windows Start menu → YAWL → User Manual.
  • You can also try the Yawl issues list. Make sure that you view “All Issues”. By default, only “Open Issues” are displayed.
  • The Oase forum.