Package org.apache.lucene.index

# Interface IndexWriterEventListener

public interface IndexWriterEventListener
A callback event listener for recording key events happened inside IndexWriter

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

## Field Summary

Fields
Modifier and Type
Field
Description
`static final IndexWriterEventListener`
`NO_OP_LISTENER`
A no-op listener that helps to save null checks

## Method Summary

Modifier and Type
Method
Description
`void`
`beginMergeOnFullFlush(MergePolicy.MergeSpecification merge)`
Invoked at the start of merge on commit
`void`
`endMergeOnFullFlush(MergePolicy.MergeSpecification merge)`
Invoked at the end of merge on commit, due to either merge completed, or merge timed out according to `IndexWriterConfig.setMaxFullFlushMergeWaitMillis(long)`

## Field Details

### NO_OP_LISTENER

static final IndexWriterEventListener NO_OP_LISTENER
A no-op listener that helps to save null checks

## Method Details

### beginMergeOnFullFlush

void beginMergeOnFullFlush(MergePolicy.MergeSpecification merge)
Invoked at the start of merge on commit

Parameters:
  `merge` - specification to be tracked

### endMergeOnFullFlush

void endMergeOnFullFlush(MergePolicy.MergeSpecification merge)
Invoked at the end of merge on commit, due to either merge completed, or merge timed out according to `IndexWriterConfig.setMaxFullFlushMergeWaitMillis(long)`

Parameters:
  `merge` - specification to be tracked