feat(java): add Dataset.takeRows() for physical row ID access#6772
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Add a JNI binding for Rust's Dataset::take_rows(), which fetches rows by their stable physical row IDs (from the _rowid system column) rather than logical indices. Mirrors the existing take() API but uses row IDs that persist across compaction and deletion. The Rust side already exposes take_rows() -- this commit wires it through JNI to Java. Changes: - blocking_dataset.rs: nativeTakeRows JNI function + inner_take_rows - Dataset.java: takeRows() public method + nativeTakeRows native declaration - DatasetTest.java: testTakeRows with ordering verification and edge cases
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hamersaw
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May 14, 2026
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Summary
Adds
Dataset.takeRows(List<Long> rowIds, List<String> columns)to the Java SDK, mirroring Rust's existingDataset::take_rows()by adding a JNI bindingtake()accepts logical row indices (positions).takeRows()accepts physical row IDs from the_rowidsystem column — these are stable across compaction and deletion, which makes them suitable for applications that store row IDs externally (e.g., in a secondary index) and later need to fetch the corresponding row data.Changes
java/lance-jni/src/blocking_dataset.rs: JNI shimnativeTakeRows+inner_take_rows— mirrorsinner_takebut callsdataset.take_rows()instead ofdataset.take()java/src/main/java/org/lance/Dataset.java: publictakeRows()method + native declarationjava/src/test/java/org/lance/DatasetTest.java:testTakeRowscovering correctness, input-order preservation, and edge cases (empty/null rejection)