ReaderUtil (Lucene 8.5.1 API)

java.lang.Object
- org.apache.lucene.index.ReaderUtil

```
public final class ReaderUtil
extends Object
```
Common util methods for dealing with IndexReaders and IndexReaderContexts.

NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method	Description
`static IndexReaderContext`	`getTopLevelContext(IndexReaderContext context)`	Walks up the reader tree and return the given context's top level reader context, or in other words the reader tree's root context.
`static int`	`subIndex(int n, int[] docStarts)`	Returns index of the searcher/reader for document `n` in the array used to construct this searcher/reader.
`static int`	`subIndex(int n, List<LeafReaderContext> leaves)`	Returns index of the searcher/reader for document `n` in the array used to construct this searcher/reader.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - getTopLevelContext
```
public static IndexReaderContext getTopLevelContext(IndexReaderContext context)
```
    Walks up the reader tree and return the given context's top level reader context, or in other words the reader tree's root context.
  - subIndex
```
public static int subIndex(int n,
                           int[] docStarts)
```
    Returns index of the searcher/reader for document n in the array used to construct this searcher/reader.
  - subIndex
```
public static int subIndex(int n,
                           List<LeafReaderContext> leaves)
```
    Returns index of the searcher/reader for document n in the array used to construct this searcher/reader.