org.apache.lucene.index

Class Fields

java.lang.Object

org.apache.lucene.index.Fields

All Implemented Interfaces:

Iterable<String>

Direct Known Subclasses:

FieldsProducer, FilterLeafReader.FilterFields, MultiFields

public abstract class Fields
extends Object
implements Iterable<String>

Provides a Terms index for fields that have it, and lists which fields do. This is primarily an internal/experimental API (see FieldsProducer), although it is also used to expose the set of term vectors per document.

WARNING: This API is experimental and might change in incompatible ways in the next release.

Field Summary

Fields

Modifier and Type	Field and Description
static Fields[]	EMPTY_ARRAY Zero-length Fields array.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Fields() Sole constructor.

Method Summary

Modifier and Type	Method and Description
abstract Iterator<String>	iterator() Returns an iterator that will step through all fields names.
abstract int	size() Returns the number of fields or -1 if the number of distinct field names is unknown.
abstract Terms	terms(String field) Get the Terms for this field.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Field Detail

EMPTY_ARRAY

public static final Fields[] EMPTY_ARRAY

Zero-length Fields array.

Constructor Detail

Fields

protected Fields()

Sole constructor. (For invocation by subclass constructors, typically implicit.)

Method Detail

iterator

public abstract Iterator<String> iterator()

Returns an iterator that will step through all fields names. This will not return null.

Specified by:

iterator in interface Iterable<String>

terms

public abstract Terms terms(String field)
                     throws IOException

Get the Terms for this field. This will return null if the field does not exist.

Throws:

IOException

size

public abstract int size()

Returns the number of fields or -1 if the number of distinct field names is unknown. If >= 0, iterator() will return as many field names.