org.apache.lucene.index
Class Terms

java.lang.Object
  org.apache.lucene.index.Terms

Direct Known Subclasses:

BlockTreeTermsReader.FieldReader, FilterAtomicReader.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

static Terms[]

EMPTY_ARRAY Zero-length array of Terms.

Constructor Summary

protected

Terms() Sole constructor.

Method Summary

abstract Comparator<BytesRef>	getComparator() Return the BytesRef Comparator used to sort terms provided by the iterator.
abstract int	getDocCount() Returns the number of documents that have at least one term for this field, or -1 if this measure isn't stored by the codec.
abstract long	getSumDocFreq() Returns the sum of TermsEnum.docFreq() for all terms in this field, or -1 if this measure isn't stored by the codec.
abstract long	getSumTotalTermFreq() Returns the sum of TermsEnum.totalTermFreq() for all terms in this field, or -1 if this measure isn't stored by the codec (or if this fields omits term freq and positions).
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 that are accepted by the provided CompiledAutomaton.
abstract TermsEnum	iterator(TermsEnum reuse) 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(TermsEnum reuse)
                            throws IOException

Returns an iterator that will step through all terms. This method will not return null. If you have a previous TermsEnum, for example from a different field, you can pass it for possible reuse if the implementation can do so.

Throws:

IOException

intersect

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

Returns a TermsEnum that iterates over all terms that are accepted by the provided CompiledAutomaton. If the startTerm is provided then the returned enum will only accept 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.

NOTE: the returned TermsEnum cannot seek

.

Throws:

IOException

getComparator

public abstract Comparator<BytesRef> getComparator()

Return the BytesRef Comparator used to sort terms provided by the iterator. This method may return null if there are no terms. This method may be invoked many times; it's best to cache a single instance & reuse it.

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, or -1 if this measure isn't stored by the codec (or if this fields omits term freq and positions). 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, 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

getDocCount

public abstract int getDocCount()
                         throws IOException

Returns the number of documents that have at least one term 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

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.