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AutoValue: Allow using a Comparator for fluent building #1910
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Hi, I found an internal thread (bug 209951563, about 3.5 years ago) in which @eamonnmcmanus discussed this with another user. There, he suggested your first option, which he illustrated as follows:
@AutoValue.Builder public abstract static class Builder { private final ImmutableSortedSet.Builder<SomeProto> someSetBuilder = someSetBuilder(COMPARATOR); abstract ImmutableSortedSet.Builder<SomeProto> someSetBuilder( Comparator<SomeProto> comparator); public final Builder addSome(SomeProto value) { someSetBuilder.add(value); return this; } public abstract MyClass build(); }
He'll probably have better judgment than I would as to whether it's time to document this. In the meantime, it is at least good that we have this external issue about it, so thanks for filing.
I think the right solution here is to allow extra calls to
someSetBuilder(comparator)provided that thecomparatoris the same in each case. As @cpovirk notes, that is already tracked in internal bug 209951563. (Comparatorinstances will typically only ever be equal if they are identical, but I think we can useequalsanyway.)This looks like a good regression-test candidate around
AutoValue: Allow using a Comparator for fluent building. A focused test that reproduces the failing path and asserts the expected output/error would make future triage much easier than relying on the broader job failure alone.
Hello!
I am using AutoValue
1.11.0(and Java 21) and I'm trying to use anImmutableSortedSetin anAutoValue, and that has anAutoValue.Builder. I'd like to pass in aComparatorso that I can decide how the set gets ordered.I'm also really fond of the fluent builder style, and I've been using what is described here in the builders how-to.
However, that breaks when I'm trying to use a
Comparator. The generated code (rightly) does not let me callImmutableSortedSet.Builder<Element> elementsBuilder(Comparator comparator)more than once. The pattern given in the how-to, however, would have me do that. I've tried having it also generate aImmutableSortedSet.Builder<Element> elementsBuilder(), but if both are present, it only generates the no-arg method.I can see some workarounds, and I'm probably going to try them in the meantime.
elementsBuilderin the abstract classElementclass in this case, so I could implementComparable<Element>(could get messy with inheritances though)Consumer<ImmutableSortedSet.Builder<Element>>argument?I can see trying to generate both the one-arg and the no-arg methods getting messy because it wouldn't be possible to really enforce which gets called first/which to initialize the sub-builder with. I'm not sure about other possible generated solutions.
Is there an official recommendation for how to do this, or documentation that I missed reading? I've read through 984 and friends, but I haven't found anything mixing the one-arg constructor and the fluent builder.
Thank you for your help!