## Uses of Interface
org.apache.lucene.util.Unwrappable

- Packages that use Unwrappable
  Package | Description
  --- | ---
  org.apache.lucene.analysis | Text analysis.
  org.apache.lucene.index | Code to maintain and access indices.
  org.apache.lucene.search | Code to search indices.

- - ### Uses of Unwrappable in org.apache.lucene.analysis

    Classes in org.apache.lucene.analysis that implement Unwrappable
    Modifier and Type | Class | Description
    --- | --- | ---
    `class` | `CachingTokenFilter` | This class can be used if the token attributes of a TokenStream are intended to be consumed more than once.
    `class` | `FilteringTokenFilter` | Abstract base class for TokenFilters that may remove tokens.
    `class` | `GraphTokenFilter` | An abstract TokenFilter that exposes its input stream as a graph
    `class` | `LowerCaseFilter` | Normalizes token text to lower case.
    `class` | `StopFilter` | Removes stop words from a token stream.
    `class` | `TokenFilter` | A TokenFilter is a TokenStream whose input is another TokenStream.

  - ### Uses of Unwrappable in org.apache.lucene.index

    Classes in org.apache.lucene.index that implement Unwrappable
    Modifier and Type | Class | Description
    --- | --- | ---
    `static class` | `FilterLeafReader.FilterPostingsEnum` | Base class for filtering `PostingsEnum` implementations.
    `class` | `FilterMergePolicy` | A wrapper for `MergePolicy` instances.
    `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` | `UpgradeIndexMergePolicy` | This `MergePolicy` is used for upgrading all existing segments of an index when calling `IndexWriter.forceMerge(int)`.

  - ### Uses of Unwrappable in org.apache.lucene.search

    Classes in org.apache.lucene.search that implement Unwrappable
    Modifier and Type | Class | Description
    --- | --- | ---
    `class` | `FilterScorer` | A `FilterScorer` contains another `Scorer`, which it uses as its basic source of data, possibly transforming the data along the way or providing additional functionality.