Thanks for the prompt reply, Jacques. I’ll explore your suggestions and let you know what I find.
> On Dec 2, 2021, at 1:33 PM, Jacques Nadeau <jacq...@apache.org> wrote: > > Hey Julian, > > To me, there are currently three avenues I envisioned for extension project > use: > 1. Use the Immutable project or similar alternatives (e.g. [1]) > 2. Write a concrete class that implements the declared interface. > 3. Use a record metaphor appropriate to the environment you're in that > implements the interface (Record in java 14+, Data class in Kotlin, etc) > > There is a fourth option, which is extending Immutable generated > code. Because Immutables was new in 1.28, I wanted to avoid introducing new > surface area directly related to the Immutables compiler/compiled class and > thus made all the implementations package private [1]. I felt this was > safer than introducing these directly but if we feel like that is something > we should expose, it would be a relatively straightforward change. Note > that the current pattern is only producing code for concrete subclasses of > RelRule.Config for specific rules, not the generic RelRule.Config which is > only an abstract interface. > > Given your constraints, I would explore #2 or #3 (and would love to hear > feedback on #4). > > One other question that comes to mind is that is this a pain more in > specifically the concept of new direct subclasses of RelRule.Config or > subclasses of other concrete rule config subclasses. > > [1] https://github.com/Randgalt/record-builder > [2] > https://github.com/apache/calcite/blob/master/core/src/main/java/org/apache/calcite/CalciteImmutable.java#L30 > > On Thu, Dec 2, 2021 at 12:20 PM Julian Hyde <jhyde.apa...@gmail.com> wrote: > >> I’m trying to write a planner rule in a dependent project. (What what it’s >> worth, the project is not open source, and is implemented in Kotlin.) I >> don’t want to make the dependent project depend on the Immutables library, >> because that introduces an annotation processor and might destabilize our >> build. >> >> I need to implement RelRule.Config in order to override the toRule method >> to create an instance of my rule. But as RelRule.Config uses Immutables, it >> does not have an implementation that I can subclass. >> >> Has anyone else run into this problem? >> >> Julian >> >>
