org.apache.lucene.index

Class MultiTermsEnum

java.lang.Object

org.apache.lucene.index.TermsEnum

org.apache.lucene.index.MultiTermsEnum

All Implemented Interfaces:

BytesRefIterator

public final class MultiTermsEnum
extends TermsEnum

Exposes TermsEnum API, merged from TermsEnum API of sub-segments. This does a merge sort, by term text, of the sub-readers.

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

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.lucene.index.TermsEnum

TermsEnum.SeekStatus

Field Summary

Fields inherited from class org.apache.lucene.index.TermsEnum

EMPTY

Constructor Summary

Constructors

Constructor and Description
MultiTermsEnum(ReaderSlice[] slices) Sole constructor.

Method Summary

Modifier and Type	Method and Description
int	docFreq() Returns the number of documents containing the current term.
org.apache.lucene.index.MultiTermsEnum.TermsEnumWithSlice[]	getMatchArray() Returns sub-reader slices positioned to the current term.
int	getMatchCount() Returns how many sub-reader slices contain the current term.
BytesRef	next() Increments the iteration to the next BytesRef in the iterator.
long	ord() Returns ordinal position for current term.
PostingsEnum	postings(PostingsEnum reuse, int flags) Get PostingsEnum for the current term, with control over whether freqs, positions, offsets or payloads are required.
TermsEnum	reset(org.apache.lucene.index.MultiTermsEnum.TermsEnumIndex[] termsEnumsIndex) The terms array must be newly created TermsEnum, ie BytesRefIterator.next() has not yet been called.
TermsEnum.SeekStatus	seekCeil(BytesRef term) Seeks to the specified term, if it exists, or to the next (ceiling) term.
boolean	seekExact(BytesRef term) Attempts to seek to the exact term, returning true if the term is found.
void	seekExact(long ord) Seeks to the specified term by ordinal (position) as previously returned by TermsEnum.ord().
BytesRef	term() Returns current term.
String	toString()
long	totalTermFreq() Returns the total number of occurrences of this term across all documents (the sum of the freq() for each doc that has this term).

Methods inherited from class org.apache.lucene.index.TermsEnum

attributes, postings, seekExact, termState

Methods inherited from class java.lang.Object

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

Constructor Detail

MultiTermsEnum

public MultiTermsEnum(ReaderSlice[] slices)

Sole constructor.

Parameters:

slices - Which sub-reader slices we should merge.

Method Detail

getMatchCount

public int getMatchCount()

Returns how many sub-reader slices contain the current term. @see #getMatchArray

getMatchArray

public org.apache.lucene.index.MultiTermsEnum.TermsEnumWithSlice[] getMatchArray()

Returns sub-reader slices positioned to the current term.

term

public BytesRef term()

Description copied from class: TermsEnum

Returns current term. Do not call this when the enum is unpositioned.

Specified by:

term in class TermsEnum

reset

public TermsEnum reset(org.apache.lucene.index.MultiTermsEnum.TermsEnumIndex[] termsEnumsIndex)
                throws IOException

The terms array must be newly created TermsEnum, ie BytesRefIterator.next() has not yet been called.

Throws:

IOException

seekExact

public boolean seekExact(BytesRef term)
                  throws IOException

Description copied from class: TermsEnum

Attempts to seek to the exact term, returning true if the term is found. If this returns false, the enum is unpositioned. For some codecs, seekExact may be substantially faster than TermsEnum.seekCeil(org.apache.lucene.util.BytesRef).

Overrides:

seekExact in class TermsEnum

Throws:

IOException

seekCeil

public TermsEnum.SeekStatus seekCeil(BytesRef term)
                              throws IOException

Description copied from class: TermsEnum

Seeks to the specified term, if it exists, or to the next (ceiling) term. Returns SeekStatus to indicate whether exact term was found, a different term was found, or EOF was hit. The target term may be before or after the current term. If this returns SeekStatus.END, the enum is unpositioned.

Specified by:

seekCeil in class TermsEnum

Throws:

IOException

seekExact

public void seekExact(long ord)

Description copied from class: TermsEnum

Seeks to the specified term by ordinal (position) as previously returned by TermsEnum.ord(). The target ord may be before or after the current ord, and must be within bounds.

Specified by:

seekExact in class TermsEnum

ord

public long ord()

Description copied from class: TermsEnum

Returns ordinal position for current term. This is an optional method (the codec may throw UnsupportedOperationException). Do not call this when the enum is unpositioned.

Specified by:

ord in class TermsEnum

next

public BytesRef next()
              throws IOException

Description copied from interface: BytesRefIterator

Increments the iteration to the next BytesRef in the iterator. Returns the resulting BytesRef or null if the end of the iterator is reached. The returned BytesRef may be re-used across calls to next. After this method returns null, do not call it again: the results are undefined.

Returns:

the next BytesRef in the iterator or null if the end of the iterator is reached.

Throws:

IOException - If there is a low-level I/O error.

docFreq

public int docFreq()
            throws IOException

Description copied from class: TermsEnum

Returns the number of documents containing the current term. Do not call this when the enum is unpositioned. TermsEnum.SeekStatus.END.

Specified by:

docFreq in class TermsEnum

Throws:

IOException

totalTermFreq

public long totalTermFreq()
                   throws IOException

Description copied from class: TermsEnum

Returns the total number of occurrences of this term across all documents (the sum of the freq() for each doc that has this term). This will be -1 if the codec doesn't support this measure. Note that, like other term measures, this measure does not take deleted documents into account.

Specified by:

totalTermFreq in class TermsEnum

Throws:

IOException

postings

public PostingsEnum postings(PostingsEnum reuse,
                             int flags)
                      throws IOException

Description copied from class: TermsEnum

Get PostingsEnum for the current term, with control over whether freqs, positions, offsets or payloads are required. Do not call this when the enum is unpositioned. This method may return null if the postings information required is not available from the index

NOTE: the returned iterator may return deleted documents, so deleted documents have to be checked on top of the PostingsEnum.

Specified by:

postings in class TermsEnum

Parameters:

reuse - pass a prior PostingsEnum for possible reuse

flags - specifies which optional per-document values you require; see PostingsEnum.FREQS

Throws:

IOException

toString

public String toString()

Overrides:

toString in class Object