Package org.apache.lucene.index

Class Fields

java.lang.Object

org.apache.lucene.index.Fields

All Implemented Interfaces:

Iterable<String>

Direct Known Subclasses:

FieldsProducer, FilterAtomicReader.FilterFields, MultiFields

public abstract class Fields
extends Object
implements Iterable<String>

Flex API for access to fields and terms

Field Summary

Fields

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

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	Fields()	Sole constructor.

Method Summary

Modifier and Type	Method	Description
long	getUniqueTermCount()	Deprecated. iterate fields and add their size() instead.
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 Details

EMPTY_ARRAY

public static final Fields[] EMPTY_ARRAY

Zero-length Fields array.

Constructor Details

Fields

protected Fields()

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

Method Details

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.

getUniqueTermCount

@Deprecated
public long getUniqueTermCount()
                        throws IOException

Deprecated.

iterate fields and add their size() instead. this method is only provided as a transition mechanism to access this statistic for 3.x indexes, which do not have this statistic per-field.

Returns the number of terms for all fields, or -1 if this measure isn't stored by the codec. Note that, just like other term measures, this measure does not take deleted documents into account.

Throws:

IOException

See Also:

• Terms.size()