org.apache.lucene.index

Class Terms

java.lang.Object

org.apache.lucene.index.Terms

Direct Known Subclasses:

FieldReader, FilterLeafReader.FilterTerms, MultiTerms

public abstract class Terms
extends Object

Access to the terms in a specific field. See Fields.

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 Terms[]	EMPTY_ARRAY Zero-length array of Terms.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Terms() Sole constructor.

Method Summary

Modifier and Type	Method and Description
abstract int	getDocCount() Returns the number of documents that have at least one term for this field.
BytesRef	getMax() Returns the largest term (in lexicographic order) in the field.
BytesRef	getMin() Returns the smallest term (in lexicographic order) in the field.
Object	getStats() Expert: returns additional information about this Terms instance for debugging purposes.
abstract long	getSumDocFreq() Returns the sum of TermsEnum.docFreq() for all terms in this field.
abstract long	getSumTotalTermFreq() Returns the sum of TermsEnum.totalTermFreq() for all terms in this field.
abstract boolean	hasFreqs() Returns true if documents in this field store per-document term frequency (PostingsEnum.freq()).
abstract boolean	hasOffsets() Returns true if documents in this field store offsets.
abstract boolean	hasPayloads() Returns true if documents in this field store payloads.
abstract boolean	hasPositions() Returns true if documents in this field store positions.
TermsEnum	intersect(CompiledAutomaton compiled, BytesRef startTerm) Returns a TermsEnum that iterates over all terms and documents that are accepted by the provided CompiledAutomaton.
abstract TermsEnum	iterator() Returns an iterator that will step through all terms.
abstract long	size() Returns the number of terms for this field, or -1 if this measure isn't stored by the codec.

Methods inherited from class java.lang.Object

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

Field Detail

EMPTY_ARRAY

public static final Terms[] EMPTY_ARRAY

Zero-length array of Terms.

Constructor Detail

Terms

protected Terms()

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

Method Detail

iterator

public abstract TermsEnum iterator()
                            throws IOException

Returns an iterator that will step through all terms. This method will not return null.

Throws:

IOException

intersect

public TermsEnum intersect(CompiledAutomaton compiled,
                           BytesRef startTerm)
                    throws IOException

Returns a TermsEnum that iterates over all terms and documents that are accepted by the provided CompiledAutomaton. If the startTerm is provided then the returned enum will only return terms > startTerm, but you still must call next() first to get to the first term. Note that the provided startTerm must be accepted by the automaton.

This is an expert low-level API and will only work for NORMAL compiled automata. To handle any compiled automata you should instead use CompiledAutomaton.getTermsEnum(org.apache.lucene.index.Terms) instead.

NOTE: the returned TermsEnum cannot seek

.

Throws:

IOException

size

public abstract long size()
                   throws IOException

Returns the number of terms for this field, 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

getSumTotalTermFreq

public abstract long getSumTotalTermFreq()
                                  throws IOException

Returns the sum of TermsEnum.totalTermFreq() for all terms in this field. Note that, just like other term measures, this measure does not take deleted documents into account.

Throws:

IOException

getSumDocFreq

public abstract long getSumDocFreq()
                            throws IOException

Returns the sum of TermsEnum.docFreq() for all terms in this field. Note that, just like other term measures, this measure does not take deleted documents into account.

Throws:

IOException

getDocCount

public abstract int getDocCount()
                         throws IOException

Returns the number of documents that have at least one term for this field. Note that, just like other term measures, this measure does not take deleted documents into account.

Throws:

IOException

hasFreqs

public abstract boolean hasFreqs()

Returns true if documents in this field store per-document term frequency (PostingsEnum.freq()).

hasOffsets

public abstract boolean hasOffsets()

Returns true if documents in this field store offsets.

hasPositions

public abstract boolean hasPositions()

Returns true if documents in this field store positions.

hasPayloads

public abstract boolean hasPayloads()

Returns true if documents in this field store payloads.

getMin

public BytesRef getMin()
                throws IOException

Returns the smallest term (in lexicographic order) in the field. Note that, just like other term measures, this measure does not take deleted documents into account. This returns null when there are no terms.

Throws:

IOException

getMax

public BytesRef getMax()
                throws IOException

Returns the largest term (in lexicographic order) in the field. Note that, just like other term measures, this measure does not take deleted documents into account. This returns null when there are no terms.

Throws:

IOException

getStats

public Object getStats()
                throws IOException

Expert: returns additional information about this Terms instance for debugging purposes.

Throws:

IOException