Shadow variable listener

[Patrick Ondreovici]

Hi, I'm curious if it is possible to use the same listener for 2 shadow variables, so that the listener will be called one time for both variables.

[Jiří Locker]

Hi Patrick,

If I understand your question correctly, the answer is no. The variable listener is called for each source variable independently. So even when there is a move that changes both source variables of the listener, it will result in two separate invocations of before/afterVariableChanged() on the variable listener.

Does that cause any issues in your use case?

Jiri

[holger brandl]

Hi there,

isn't this precisely the use-case for a PiggyBackShadowVariable (see https://docs.optaplanner.org/latest/optaplanner-docs/html_single/index.html#_piggyback_shadow_variable)? From my understanding it should allow updating two shadow variables more efficiently with one listener.

Best Holger

[Patrick Ondreovici]

Thanks for the answer

[Jiří Locker]

I think Holger is right and my previous answer is not relevant because I missed the word "shadow".