## Uses of Class
org.apache.lucene.index.MergePolicy

Packages that use MergePolicy
org.apache.lucene.index: Code to maintain and access indices.

### Uses of MergePolicy in org.apache.lucene.index

Subclasses of MergePolicy in org.apache.lucene.index
`class` `FilterMergePolicy` A wrapper for `MergePolicy` instances.
`class` `LogByteSizeMergePolicy` This is a `LogMergePolicy` that measures size of a segment as the total byte size of the segment's files.
`class` `LogDocMergePolicy` This is a `LogMergePolicy` that measures size of a segment as the number of documents (not taking deletions into account).
`class` `LogMergePolicy` This class implements a `MergePolicy` that tries to merge segments into levels of exponentially increasing size, where each level has fewer segments than the value of the merge factor.
`class` `NoMergePolicy` A `MergePolicy` which never returns merges to execute.
`class` `OneMergeWrappingMergePolicy` A wrapping merge policy that wraps the `MergePolicy.OneMerge` objects returned by the wrapped merge policy.
`class` `SoftDeletesRetentionMergePolicy` This `MergePolicy` allows to carry over soft deleted documents across merges.
`class` `TieredMergePolicy` Merges segments of approximately equal size, subject to an allowed number of segments per tier.
`class` `UpgradeIndexMergePolicy` This `MergePolicy` is used for upgrading all existing segments of an index when calling `IndexWriter.forceMerge(int)`.

Fields in org.apache.lucene.index declared as MergePolicy
`protected MergePolicy` FilterMergePolicy.`in` The wrapped `MergePolicy`.
`static MergePolicy` NoMergePolicy.`INSTANCE` Singleton instance.
`protected MergePolicy` LiveIndexWriterConfig.`mergePolicy` `MergePolicy` for selecting merges.

Methods in org.apache.lucene.index that return MergePolicy
`MergePolicy` LiveIndexWriterConfig.`getMergePolicy()` Returns the current MergePolicy in use by this writer.
`MergePolicy` IndexWriterConfig.`getMergePolicy()`

Methods in org.apache.lucene.index with parameters of type MergePolicy
`LiveIndexWriterConfig` LiveIndexWriterConfig.`setMergePolicy(MergePolicy mergePolicy)` Expert: `MergePolicy` is invoked whenever there are changes to the segments in the index.
`IndexWriterConfig` IndexWriterConfig.`setMergePolicy(MergePolicy mergePolicy)`

Constructors in org.apache.lucene.index with parameters of type MergePolicy
Constructor and Description
`FilterMergePolicy(MergePolicy in)` Creates a new filter merge policy instance wrapping another.
`OneMergeWrappingMergePolicy(MergePolicy in, UnaryOperator<MergePolicy.OneMerge> wrapOneMerge)` Constructor
`SoftDeletesRetentionMergePolicy(String field, Supplier<Query> retentionQuerySupplier, MergePolicy in)` Creates a new `SoftDeletesRetentionMergePolicy`
`UpgradeIndexMergePolicy(MergePolicy in)` Wrap the given `MergePolicy` and intercept forceMerge requests to only upgrade segments written with previous Lucene versions.