Most common issues and how to troubleshoot them

These are some of the most common issues captured by users when seting up or running ALPypeOpt:

  • You missed implementing ALPypeOptClientController required methods.

  • You get a ClassCastException when running the example models.

If you face an issue that doesn’t appear in this list and are unable to solve it, feel free to raise it here as others might benefit from it.

You missed the implementation of ALPypeOptClientController

You can fail to implement ALPypeOptClientController in two ways:

  • You didn’t add ALPypeOptClientController to the list of interfaces of your root (Main) model. When that happens, the python side or alpypeopt won’t be able to control your simulation model in the way that is required. You will be getting the following class casting exception:

java.lang.ClassCastException: class gasprocessingplant.Main cannot be cast to class com.alpypeopt.ALPypeOptClientController (gasprocessingplant.Main and com.alpypeopt.ALPypeOptClientController are in unnamed module of loader 'app')
at com.alpypeopt.ALPypeOptConnector.getClientController(ALPypeOptConnector.java:226)
at com.alpypeopt.RLJavaControllerImpl.setupAndRun(RLJavaControllerImpl.java:118)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at py4j.reflection.MethodInvoker.invoke(MethodInvoker.java:244)
at py4j.reflection.ReflectionEngine.invoke(ReflectionEngine.java:357)
at py4j.Gateway.invoke(Gateway.java:282)
at py4j.commands.AbstractCommand.invokeMethod(AbstractCommand.java:132)
at py4j.commands.CallCommand.execute(CallCommand.java:79)
at py4j.ClientServerConnection.waitForCommands(ClientServerConnection.java:182)
at py4j.ClientServerConnection.run(ClientServerConnection.java:106)
at java.base/java.lang.Thread.run(Thread.java:834)

From the python side you will be able to read:

It seems you haven't implemented 'ALPypeOptClientController'. Go to your 'root' agent (where you should have dropped 'ALPypeOptConnector') and search for 'Advanced Java / Implements (comma-separated list of interfaces)'. Then add 'ALPypeOptClientController' to your list and implement the required functions

  • You forgot to implement ALPypeOptClientController functions. This is a more visual error, as it will be highlighted during your AnyLogic model compilation. In a way that is good, because it indicates clearly that you are missing something. You’ll see something like:

For both case, you might want to review how it is done here.

You get a ClassCastException when running the example models

Some people has reported a CastClassExeption error when running the example models without any modification made on their side. This is due to a dependency on the AnyLogic version that exported the ALPypeLibrary and the uploader. To avoid this problem, ALPypeLibrary has been exported for different AnyLogic versions. Please ensure to use the right one.

In case you continue facing an exception of this sort, do not hesitate to reach out to marcescandellmari@gmail.com to seek for help.

Here’s a screenshot of the error:

AnyLogic Cast Exception error