Package org.apache.lucene.index

# Interface IndexWriter.IndexReaderWarmer

All Known Implementing Classes:
  `SimpleMergedSegmentWarmer`

Enclosing class:
  `IndexWriter`

Functional Interface:
  This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface public static interface IndexWriter.IndexReaderWarmer
If `DirectoryReader.open(IndexWriter)` has been called (ie, this writer is in near real-time mode), then after a merge completes, this class can be invoked to warm the reader on the newly merged segment, before the merge commits. This is not required for near real-time search, but will reduce search latency on opening a new near real-time reader after a merge completes.

WARNING: This API is experimental and might change in incompatible ways in the next release.

  NOTE: `warm(LeafReader)` is called before any deletes have been carried over to the merged segment.

## Method Summary

Modifier and Type
Method
Description
`void`
`warm(LeafReader reader)`
Invoked on the `LeafReader` for the newly merged segment, before that segment is made visible to near-real-time readers.

## Method Details

### warm

void warm(LeafReader reader) throws IOException
Invoked on the `LeafReader` for the newly merged segment, before that segment is made visible to near-real-time readers.

Throws:
  `IOException`