How to mimic Optaplanner 7's MoveIteratorFactoryToMoveSelectorBridge in Optaplanner 8 - kotlin

Question

We have implemented a custom construction heuristic with Optaplanner 7. We didn't use a simple CustomPhaseCommand; Instead, we extend MoveSelectorConfig and override buildBaseMoveSelector to return our own MoveFactory wrapped in a MoveIteratorFactoryToMoveSelectorBridge. We decided to do so, because it gives us the following advantages:
global termination config is supported out of the box
type safe configuration from code (no raw Strings)
With Optaplanner 8 the method buildBaseMoveSelector is gone from the MoveSelectorConfig API and building a custom config class seems to be prevented in the new implementation of MoveSelectorFactory.
Is it still possible to inject a proper custom construction heuristic into the Optaplanner 8 configuration and if yes, how? Or should we be using a CustomPhaseCommand with a custom self-implemented termination?
EDIT:
For clarity, in Optaplanner 7 we had the following snippet in our Optaplanner-config (defined in kotlin code):
ConstructionHeuristicPhaseConfig().apply {
foragerConfig = ConstructionHeuristicForagerConfig().apply {
pickEarlyType = FIRST_FEASIBLE_SCORE
}
entityPlacerConfig = QueuedEntityPlacerConfig().apply {
moveSelectorConfigList = listOf(
CustomMoveSelectorConfig().apply {
someProperty = 1
otherProperty = 0
}
)
}
},
CustomMoveSelectorConfig extends MoveSelectorConfig and overrides buildBaseMoveSelector:
class CustomMoveSelectorConfig(
var someProperty: Int = 0,
var otherProperty: Int = 0,
) : MoveSelectorConfig<CustomMoveSelectorConfig>() {
override fun buildBaseMoveSelector(
configPolicy: HeuristicConfigPolicy?,
minimumCacheType: SelectionCacheType?,
randomSelection: Boolean,
): MoveSelector {
return MoveIteratorFactoryToMoveSelectorBridge(
CustomMoveFactory(someProperty, otherProperty),
randomSelection
)
}
To summarize: We really need to plug our own MoveSelector with the custom factory. I think this is not possible with Optaplanner 8 at the moment.

Answer 1

Interesting extension.
Motivation for the changes in 8:
the buildBaseMoveSelector was not public API (the config package was not in the api package, we only guaranteed XML backwards compatibility for package config in 7). Now, we also guarantee API backwards compatibility for package config, so including programmatic configuration, because we moved all build* methods out of it.
In 8.2 or later we want to internalize the configuration in the SolverFactory, so we can build thousands of Solver instances faster. For example, loading classes wouldn't to be done only at SolverFactory build, once, no longer at every Solver build.
Anyway, let's first see if you can use the default way to override the moves of the CH, by explicitly configuring the queuedEntityPlacer and it's MoveIteratorFactory? https://docs.optaplanner.org/latestFinal/optaplanner-docs/html_single/#allocateEntityFromQueueConfiguration
I guess not, because you'd need mimic support... for the selected entity you need to generate n moves, but always the same entity during 1 placement (hence the need for mimicing).
Clearly, the changes in 8 prevent users from plugging in their own MoveSelectors (= which is an internal API, but anyway). We might be able to add an internal API to allow that again.