org.apache.lucene.index

Interface IndexSorter

All Known Implementing Classes:

IndexSorter.DoubleSorter, IndexSorter.FloatSorter, IndexSorter.IntSorter, IndexSorter.LongSorter, IndexSorter.StringSorter

public interface IndexSorter

Handles how documents should be sorted in an index, both within a segment and between segments. Implementers must provide the following methods: getDocComparator(LeafReader,int) - an object that determines how documents within a segment are to be sorted getComparableProviders(List) - an array of objects that return a sortable long value per document and segment getProviderName() - the SPI-registered name of a SortFieldProvider to serialize the sort The companion SortFieldProvider should be registered with SPI via META-INF/services

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	IndexSorter.ComparableProvider Used for sorting documents across segments
static interface	IndexSorter.DocComparator A comparator of doc IDs, used for sorting documents within a segment
static class	IndexSorter.DoubleSorter Sorts documents based on double values from a NumericDocValues instance
static class	IndexSorter.FloatSorter Sorts documents based on float values from a NumericDocValues instance
static class	IndexSorter.IntSorter Sorts documents based on integer values from a NumericDocValues instance
static class	IndexSorter.LongSorter Sorts documents based on long values from a NumericDocValues instance
static interface	IndexSorter.NumericDocValuesProvider Provide a NumericDocValues instance for a LeafReader
static interface	IndexSorter.SortedDocValuesProvider Provide a SortedDocValues instance for a LeafReader
static class	IndexSorter.StringSorter Sorts documents based on terms from a SortedDocValues instance

Method Summary

Modifier and Type	Method and Description
IndexSorter.ComparableProvider[]	getComparableProviders(List<? extends LeafReader> readers) Get an array of IndexSorter.ComparableProvider, one per segment, for merge sorting documents in different segments
IndexSorter.DocComparator	getDocComparator(LeafReader reader, int maxDoc) Get a comparator that determines the sort order of docs within a single Reader.
String	getProviderName() The SPI-registered name of a SortFieldProvider that will deserialize the parent SortField

Method Detail

getComparableProviders

IndexSorter.ComparableProvider[] getComparableProviders(List<? extends LeafReader> readers)
                                                 throws IOException

Get an array of IndexSorter.ComparableProvider, one per segment, for merge sorting documents in different segments

Parameters:

readers - the readers to be merged

Throws:

IOException

getDocComparator

IndexSorter.DocComparator getDocComparator(LeafReader reader,
                                           int maxDoc)
                                    throws IOException

Get a comparator that determines the sort order of docs within a single Reader. NB We cannot simply use the FieldComparator API because it requires docIDs to be sent in-order. The default implementations allocate array[maxDoc] to hold native values 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

Parameters:

reader - the Reader to sort

maxDoc - the number of documents in the Reader

Throws:

IOException

getProviderName

String getProviderName()

The SPI-registered name of a SortFieldProvider that will deserialize the parent SortField