DATACASS-529 - Allow slice queries using reactive repositories. #128
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hleb-albau
changed the title
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Thanks a lot, we'll take a look as soon as we have time. |
| * @param rowMapper must not be {@literal null}. | ||
| * @return the resulting {@link Slice}. | ||
| */ | ||
| static <T> Mono<Slice<T>> readSlice(ReactiveResultSet resultSet, Integer fetchSize, Function<Row, T> rowMapper) { |
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We can't introduce dependencies to reactive types here as we want the module to run without reactive dependencies as well.
We also need to be careful about fetching/reading progress. If the fetch size differs from the actual number of rows returned for a page, we might request the next page without intending to do so. I think we need another method on ReactiveResultSet that gives us a Flux without transparent next page fetching.
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| * @param statement the CQL statement, must not be {@literal null}. | ||
| * @param entityClass The entity type must not be {@literal null}. | ||
| * @return the result object returned by the action or {@link Mono#empty()} |
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In this case, we're mixing paradigms. We should return an empty Slice (see Page.empty()) as the query terminates without rows and the query result is the container for rows, not the rows themselves.
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Hi @mp911de, |
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Cool, thanks for your timely update. We'll take care of this one. |
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@mp911de do you have any plans when you could handle this? |
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This pull request needs some polishing before we can merge it. We intend to ship the change with the next release candidate. |
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So |
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@mp911de |
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@lukasz-gosiewski Please file a new ticket in Spring Data Cassandra. We'll see what we can do for you. |
We now support Slice queries using reactive Cassandra repositories. Repository query methods can declare Mono<Slice<T>> as their return type to query for slices without applying transparent paging. The resulting Mono always completes with a value. An empty query result returns a Mono emitting an empty Slice.
interface UserRepository extends CrudRepository<User, String> {
Mono<Slice<User>> findByLastname(String firstname, Pageable pageable);
}
Mono<Slice<User>> result =repository.findByLastname("White", CassandraPageRequest.first(1));
Original pull request: #128.
Introduce ReactiveResultSet.availableRows() to fetch rows without transparent paging. Refactor QueryUtils to extract a Slice from an Iterable. Add slice(Query, Class) to ReactiveCassandraOperations to expose a consistent API. Convert space indentation to tab indentation. Add tests. Add since tags. Add documentation. Reformat code. Original pull request: #128.
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That's merged and polished now. Thanks a lot! |
4 participants
Reactive repositories now support methods returning
Mono<Slice<T>>.Related ticket: DATACASS-529.