org.apache.lucene.index

Class DocValues

java.lang.Object

org.apache.lucene.index.DocValues

public final class DocValues
extends Object

This class contains utility methods and constants for DocValues

Method Summary

Modifier and Type	Method and Description
static BinaryDocValues	emptyBinary() An empty BinaryDocValues which returns no documents
static NumericDocValues	emptyNumeric() An empty NumericDocValues which returns no documents
static SortedDocValues	emptySorted() An empty SortedDocValues which returns BytesRef.EMPTY_BYTES for every document
static SortedNumericDocValues	emptySortedNumeric(int maxDoc) An empty SortedNumericDocValues which returns zero values for every document
static SortedSetDocValues	emptySortedSet() An empty SortedDocValues which returns BytesRef.EMPTY_BYTES for every document
static BinaryDocValues	getBinary(LeafReader reader, String field) Returns BinaryDocValues for the field, or emptyBinary() if it has none.
static NumericDocValues	getNumeric(LeafReader reader, String field) Returns NumericDocValues for the field, or emptyNumeric() if it has none.
static SortedDocValues	getSorted(LeafReader reader, String field) Returns SortedDocValues for the field, or emptySorted() if it has none.
static SortedNumericDocValues	getSortedNumeric(LeafReader reader, String field) Returns SortedNumericDocValues for the field, or emptySortedNumeric(int) if it has none.
static SortedSetDocValues	getSortedSet(LeafReader reader, String field) Returns SortedSetDocValues for the field, or emptySortedSet() if it has none.
static boolean	isCacheable(LeafReaderContext ctx, String... fields) Returns true if the specified docvalues fields have not been updated
static SortedNumericDocValues	singleton(NumericDocValues dv) Returns a multi-valued view over the provided NumericDocValues
static SortedSetDocValues	singleton(SortedDocValues dv) Returns a multi-valued view over the provided SortedDocValues
static NumericDocValues	unwrapSingleton(SortedNumericDocValues dv) Returns a single-valued view of the SortedNumericDocValues, if it was previously wrapped with singleton(NumericDocValues), or null.
static SortedDocValues	unwrapSingleton(SortedSetDocValues dv) Returns a single-valued view of the SortedSetDocValues, if it was previously wrapped with singleton(SortedDocValues), or null.

Methods inherited from class java.lang.Object

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

Method Detail

emptyBinary

public static final BinaryDocValues emptyBinary()

An empty BinaryDocValues which returns no documents

emptyNumeric

public static final NumericDocValues emptyNumeric()

An empty NumericDocValues which returns no documents

emptySorted

public static final SortedDocValues emptySorted()

An empty SortedDocValues which returns BytesRef.EMPTY_BYTES for every document

emptySortedNumeric

public static final SortedNumericDocValues emptySortedNumeric(int maxDoc)

An empty SortedNumericDocValues which returns zero values for every document

emptySortedSet

public static final SortedSetDocValues emptySortedSet()

An empty SortedDocValues which returns BytesRef.EMPTY_BYTES for every document

singleton

public static SortedSetDocValues singleton(SortedDocValues dv)

Returns a multi-valued view over the provided SortedDocValues

unwrapSingleton

public static SortedDocValues unwrapSingleton(SortedSetDocValues dv)

Returns a single-valued view of the SortedSetDocValues, if it was previously wrapped with singleton(SortedDocValues), or null.

unwrapSingleton

public static NumericDocValues unwrapSingleton(SortedNumericDocValues dv)

Returns a single-valued view of the SortedNumericDocValues, if it was previously wrapped with singleton(NumericDocValues), or null.

singleton

public static SortedNumericDocValues singleton(NumericDocValues dv)

Returns a multi-valued view over the provided NumericDocValues

getNumeric

public static NumericDocValues getNumeric(LeafReader reader,
                                          String field)
                                   throws IOException

Returns NumericDocValues for the field, or emptyNumeric() if it has none.

Returns:

docvalues instance, or an empty instance if field does not exist in this reader.

Throws:

IllegalStateException - if field exists, but was not indexed with docvalues.

IllegalStateException - if field has docvalues, but the type is not DocValuesType.NUMERIC.

IOException - if an I/O error occurs.

getBinary

public static BinaryDocValues getBinary(LeafReader reader,
                                        String field)
                                 throws IOException

Returns BinaryDocValues for the field, or emptyBinary() if it has none.

Returns:

docvalues instance, or an empty instance if field does not exist in this reader.

Throws:

IllegalStateException - if field exists, but was not indexed with docvalues.

IllegalStateException - if field has docvalues, but the type is not DocValuesType.BINARY or DocValuesType.SORTED.

IOException - if an I/O error occurs.

getSorted

public static SortedDocValues getSorted(LeafReader reader,
                                        String field)
                                 throws IOException

Returns SortedDocValues for the field, or emptySorted() if it has none.

Returns:

docvalues instance, or an empty instance if field does not exist in this reader.

Throws:

IllegalStateException - if field exists, but was not indexed with docvalues.

IllegalStateException - if field has docvalues, but the type is not DocValuesType.SORTED.

IOException - if an I/O error occurs.

getSortedNumeric

public static SortedNumericDocValues getSortedNumeric(LeafReader reader,
                                                      String field)
                                               throws IOException

Returns SortedNumericDocValues for the field, or emptySortedNumeric(int) if it has none.

Returns:

docvalues instance, or an empty instance if field does not exist in this reader.

Throws:

IllegalStateException - if field exists, but was not indexed with docvalues.

IllegalStateException - if field has docvalues, but the type is not DocValuesType.SORTED_NUMERIC or DocValuesType.NUMERIC.

IOException - if an I/O error occurs.

getSortedSet

public static SortedSetDocValues getSortedSet(LeafReader reader,
                                              String field)
                                       throws IOException

Returns SortedSetDocValues for the field, or emptySortedSet() if it has none.

Returns:

docvalues instance, or an empty instance if field does not exist in this reader.

Throws:

IllegalStateException - if field exists, but was not indexed with docvalues.

IllegalStateException - if field has docvalues, but the type is not DocValuesType.SORTED_SET or DocValuesType.SORTED.

IOException - if an I/O error occurs.

isCacheable

public static boolean isCacheable(LeafReaderContext ctx,
                                  String... fields)

Returns true if the specified docvalues fields have not been updated