Package org.elasticsearch.common.lucene.index

Class FilterableTermsEnum

java.lang.Object

org.apache.lucene.index.TermsEnum

org.elasticsearch.common.lucene.index.FilterableTermsEnum

All Implemented Interfaces:

BytesRefIterator

Direct Known Subclasses:

FreqTermsEnum

public class FilterableTermsEnum
extends TermsEnum

A frequency TermsEnum that returns frequencies derived from a collection of cached leaf termEnums. It also allows to provide a filter to explicitly compute frequencies only for docs that match the filter (heavier!).

Nested Class Summary

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

TermsEnum.SeekStatus

Field Summary

Fields

Modifier and Type	Field	Description
protected BytesRef	current
protected int	currentDocFreq
protected long	currentTotalTermFreq
protected int	docsEnumFlag
protected static int	NOT_FOUND

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

EMPTY

Constructor Summary

Constructors

Constructor	Description
FilterableTermsEnum(IndexReader reader, String field, int docsEnumFlag, Query filter)

Method Summary

Modifier and Type	Method	Description
AttributeSource	attributes()	Returns the related attributes.
int	docFreq()	Returns the number of documents containing the current term.
ImpactsEnum	impacts(int flags)	Return a ImpactsEnum.
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.SeekStatus	seekCeil(BytesRef text)	Seeks to the specified term, if it exists, or to the next (ceiling) term.
void	seekExact(long ord)	Seeks to the specified term by ordinal (position) as previously returned by TermsEnum.ord().
boolean	seekExact(BytesRef text)	Attempts to seek to the exact term, returning true if the term is found.
void	seekExact(BytesRef term, TermState state)	Expert: Seeks a specific position by TermState previously obtained from TermsEnum.termState().
BytesRef	term()	Returns current term.
TermState	termState()	Expert: Returns the TermsEnums internal state to position the TermsEnum without re-seeking the term dictionary.
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

postings

Methods inherited from class java.lang.Object

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

Field Detail

NOT_FOUND

protected static final int NOT_FOUND

See Also:

Constant Field Values

currentDocFreq

protected int currentDocFreq

currentTotalTermFreq

protected long currentTotalTermFreq

current

protected BytesRef current

docsEnumFlag

protected final int docsEnumFlag

Constructor Detail

FilterableTermsEnum

public FilterableTermsEnum(IndexReader reader,
                           String field,
                           int docsEnumFlag,
                           @Nullable
                           Query filter)
                    throws IOException

Throws:

IOException

Method Detail

term

public BytesRef term()
              throws IOException

Description copied from class: TermsEnum

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

Specified by:

term in class TermsEnum

Throws:

IOException

attributes

public AttributeSource attributes()

Description copied from class: TermsEnum

Returns the related attributes.

Specified by:

attributes in class TermsEnum

seekExact

public boolean seekExact(BytesRef text)
                  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).

Specified by:

seekExact in class TermsEnum

Returns:

true if the term is found; return false if the enum is unpositioned.

Throws:

IOException

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). Note that, like other term measures, this measure does not take deleted documents into account.

Specified by:

totalTermFreq in class TermsEnum

Throws:

IOException

seekExact

public void seekExact(long ord)
               throws IOException

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

Throws:

IOException

seekExact

public void seekExact(BytesRef term,
                      TermState state)
               throws IOException

Description copied from class: TermsEnum

Expert: Seeks a specific position by TermState previously obtained from TermsEnum.termState(). Callers should maintain the TermState to use this method. Low-level implementations may position the TermsEnum without re-seeking the term dictionary.

Seeking by TermState should only be used iff the state was obtained from the same TermsEnum instance.

NOTE: Using this method with an incompatible TermState might leave this TermsEnum in undefined state. On a segment level TermState instances are compatible only iff the source and the target TermsEnum operate on the same field. If operating on segment level, TermState instances must not be used across segments.

NOTE: A seek by TermState might not restore the AttributeSource's state. AttributeSource states must be maintained separately if this method is used.

Specified by:

seekExact in class TermsEnum

Parameters:

term - the term the TermState corresponds to

state - the TermState

Throws:

IOException

termState

public TermState termState()
                    throws IOException

Description copied from class: TermsEnum

Expert: Returns the TermsEnums internal state to position the TermsEnum without re-seeking the term dictionary.

NOTE: A seek by TermState might not capture the AttributeSource's state. Callers must maintain the AttributeSource states separately

Specified by:

termState in class TermsEnum

Throws:

IOException

See Also:

TermState, TermsEnum.seekExact(BytesRef, TermState)

seekCeil

public TermsEnum.SeekStatus seekCeil(BytesRef text)
                              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

ord

public long ord()
         throws IOException

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

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 will not return null.

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

impacts

public ImpactsEnum impacts(int flags)
                    throws IOException

Description copied from class: TermsEnum

Return a ImpactsEnum.

Specified by:

impacts in class TermsEnum

Throws:

IOException

See Also:

TermsEnum.postings(PostingsEnum, int)

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.