org.apache.lucene.index

Class Sorter

java.lang.Object

org.apache.lucene.index.Sorter

final class Sorter
extends java.lang.Object

Sorts documents of a given index by returning a permutation on the document IDs.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
(package private) static class	Sorter.DocComparator A comparator of doc IDs.
(package private) static class	Sorter.DocMap A permutation of doc IDs.
private static class	Sorter.DocValueSorter
(package private) static interface	Sorter.NumericDocValuesSupplier
(package private) static interface	Sorter.SortedDocValuesSupplier

Field Summary

Fields

Modifier and Type	Field and Description
(package private) Sort	sort

Constructor Summary

Constructors

Constructor and Description
Sorter(Sort sort) Creates a new Sorter to sort the index with sort

Method Summary

Modifier and Type	Method and Description
(package private) static Sorter.DocComparator	getDocComparator(int maxDoc, SortField sortField, Sorter.SortedDocValuesSupplier sortedProvider, Sorter.NumericDocValuesSupplier numericProvider) We cannot use the FieldComparator API because that API requires that you send it docIDs in order.
(package private) static Sorter.DocComparator	getDocComparator(LeafReader reader, SortField sortField)
java.lang.String	getID() Returns the identifier of this Sorter.
(package private) static NumericDocValues	getOrWrapNumeric(LeafReader reader, SortField sortField) Wraps a SortedNumericDocValues as a single-valued view if the field is an instance of SortedNumericSortField, returns NumericDocValues for the field otherwise.
(package private) static SortedDocValues	getOrWrapSorted(LeafReader reader, SortField sortField) Wraps a SortedSetDocValues as a single-valued view if the field is an instance of SortedSetSortField, returns SortedDocValues for the field otherwise.
(package private) static SortField.Type	getSortFieldType(SortField sortField) Returns the native sort type for SortedSetSortField and SortedNumericSortField, SortField.getType() otherwise
(package private) static boolean	isConsistent(Sorter.DocMap docMap) Check consistency of a Sorter.DocMap, useful for assertions.
private static Sorter.DocMap	sort(int maxDoc, Sorter.DocComparator comparator) Computes the old-to-new permutation over the given comparator.
(package private) Sorter.DocMap	sort(int maxDoc, Sorter.DocComparator[] comparators)
(package private) Sorter.DocMap	sort(LeafReader reader) Returns a mapping from the old document ID to its new location in the sorted index.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

sort

final Sort sort

Constructor Detail

Sorter

Sorter(Sort sort)

Creates a new Sorter to sort the index with sort

Method Detail

isConsistent

static boolean isConsistent(Sorter.DocMap docMap)

Check consistency of a Sorter.DocMap, useful for assertions.

sort

private static Sorter.DocMap sort(int maxDoc,
                                  Sorter.DocComparator comparator)

Computes the old-to-new permutation over the given comparator.

getSortFieldType

static SortField.Type getSortFieldType(SortField sortField)

Returns the native sort type for SortedSetSortField and SortedNumericSortField, SortField.getType() otherwise

getOrWrapNumeric

static NumericDocValues getOrWrapNumeric(LeafReader reader,
                                         SortField sortField)
                                  throws java.io.IOException

Wraps a SortedNumericDocValues as a single-valued view if the field is an instance of SortedNumericSortField, returns NumericDocValues for the field otherwise.

Throws:

java.io.IOException

getOrWrapSorted

static SortedDocValues getOrWrapSorted(LeafReader reader,
                                       SortField sortField)
                                throws java.io.IOException

Wraps a SortedSetDocValues as a single-valued view if the field is an instance of SortedSetSortField, returns SortedDocValues for the field otherwise.

Throws:

java.io.IOException

getDocComparator

static Sorter.DocComparator getDocComparator(LeafReader reader,
                                             SortField sortField)
                                      throws java.io.IOException

Throws:

java.io.IOException

getDocComparator

static Sorter.DocComparator getDocComparator(int maxDoc,
                                             SortField sortField,
                                             Sorter.SortedDocValuesSupplier sortedProvider,
                                             Sorter.NumericDocValuesSupplier numericProvider)
                                      throws java.io.IOException

We cannot use the FieldComparator API because that API requires that you send it docIDs in order. Note that this API allocates arrays[maxDoc] to hold the native values needed for comparison, but 1) they are transient (only alive while sorting this one segment), and 2) in the typical index sorting case, they are only used to sort newly flushed segments, which will be smaller than merged segments.

Throws:

java.io.IOException

sort

Sorter.DocMap sort(LeafReader reader)
            throws java.io.IOException

Returns a mapping from the old document ID to its new location in the sorted index. Implementations can use the auxiliary sort(int, DocComparator) to compute the old-to-new permutation given a list of documents and their corresponding values.

A return value of null is allowed and means that reader is already sorted.

NOTE: deleted documents are expected to appear in the mapping as well, they will however be marked as deleted in the sorted view.

Throws:

java.io.IOException

sort

Sorter.DocMap sort(int maxDoc,
                   Sorter.DocComparator[] comparators)
            throws java.io.IOException

Throws:

java.io.IOException

getID

public java.lang.String getID()

Returns the identifier of this Sorter.

This identifier is similar to Object.hashCode() and should be chosen so that two instances of this class that sort documents likewise will have the same identifier. On the contrary, this identifier should be different on different sorts.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object