Package org.apache.lucene.index

# Class Sorter.DocMap

java.lang.Object
org.apache.lucene.index.Sorter.DocMap

Enclosing class:
  `Sorter`

public abstract static class Sorter.DocMap extends Object
A permutation of doc IDs. For every document ID between `0` and `IndexReader.maxDoc()`, `oldToNew(newToOld(docID))` must return `docID`.

## Constructor Summary

Constructors
Modifier
Constructor
Description
`protected`
`DocMap()`
Sole constructor.

## Method Summary

Modifier and Type
Method
Description
`abstract int`
`newToOld(int docID)`
Given the ordinal of a doc ID, return its doc ID in the original index.
`abstract int`
`oldToNew(int docID)`
Given a doc ID from the original index, return its ordinal in the sorted index.
`abstract int`
`size()`
Return the number of documents in this map.

### Methods inherited from class java.lang.Object

`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

## Constructor Details

### DocMap

protected DocMap()
Sole constructor.

## Method Details

### oldToNew

public abstract int oldToNew(int docID)
Given a doc ID from the original index, return its ordinal in the sorted index.

### newToOld

public abstract int newToOld(int docID)
Given the ordinal of a doc ID, return its doc ID in the original index.

### size

public abstract int size()
Return the number of documents in this map. This must be equal to the `number of documents` of the `LeafReader` which is sorted.