## Issue
<!-- Update with the real issue number once the issue above is filed -->
Closes#5506
## Change
`CassandraEmbeddingStore` builds its backing `MetadataVectorTable` with
the configured `CassandraSimilarityMetric` (COSINE, DOT_PRODUCT, or
EUCLIDEAN), exposed via `Builder.metric(...)` and
`BuilderAstra.metric(...)`.
But both `findRelevant(...)` overloads (reached by `search(...)`)
hardcoded `.metric(CassandraSimilarityMetric.COSINE)` on the `AnnQuery`.
A store configured with EUCLIDEAN or DOT_PRODUCT was therefore queried
with the COSINE CQL similarity function, returning wrong top-K results
on a normal call path with valid input.
This PR replaces the hardcoded COSINE with
`.metric(embeddingTable.getSimilarityMetric())` in both overloads, so
search honors the configured metric. The COSINE default path is
unchanged (backward compatible).
Scope: this PR fixes only the metric passed to the query. The
EUCLIDEAN/DOT_PRODUCT relevance-score mapping
(`RelevanceScore.fromCosineSimilarity`) is a separate design question,
left to a follow-up.
Tests: added `CassandraEmbeddingStoreTest` (Mockito `ArgumentCaptor`, no
Docker/API key). It captures the `AnnQuery` passed to `similaritySearch`
and asserts the metric matches the configured one for both overloads,
plus a COSINE-default case. Verified fail-then-pass: the EUCLIDEAN
assertions fail against the pre-fix code and pass after the fix.
Note: `CassandraEmbeddingStore.java` predates the palantir-java-format
ratchet, so `spotless:apply` reformatted the whole touched file (import
ordering, line wrapping) as CI requires. Functional change is the two
`.metric(...)` lines.
## General checklist
- [X] There are no breaking changes (API, behaviour)
- [X] I have added unit and/or integration tests for my change
- [X] The tests cover both positive and negative cases
- [X] I have manually run all the unit and integration tests in the
module I have added/changed, and they are all green
- [ ] I have manually run all the unit and integration tests in the core
and main modules <!-- change is isolated to langchain4j-cassandra -->
- [ ] I have added/updated the documentation <!-- bug fix; docs added
after approval per guidelines -->
- [ ] I have added an example in the examples repo <!-- not a big
feature -->
- [ ] I have added/updated Spring Boot starter(s) <!-- not applicable
-->
<!-- Checklist for adding new maven module: not applicable -->
<!-- Checklist for adding/changing embedding store integration: no
schema/persistence change; behavior fix only -->
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