org.apache.lucene.codecs.idversion

Class IDVersionSegmentTermsEnum

java.lang.Object

org.apache.lucene.index.TermsEnum

org.apache.lucene.codecs.idversion.IDVersionSegmentTermsEnum

All Implemented Interfaces:

BytesRefIterator

public final class IDVersionSegmentTermsEnum
extends TermsEnum

Iterates through terms in this field; this class is public so users can cast it to call seekExact(BytesRef, long) for optimistic-concurreny, and also getVersion() to get the version of the currently seek'd term.

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

Method Summary

Methods

Modifier and Type	Method and Description
int	docFreq() Returns the number of documents containing the current term.
long	getVersion() Get the version of the currently seek'd term; only valid if we are positioned.
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 target) Seeks to the specified term, if it exists, or to the next (ceiling) term.
boolean	seekExact(BytesRef target) Attempts to seek to the exact term, returning true if the term is found.
boolean	seekExact(BytesRef target, long minIDVersion) Optimized version of seekExact(BytesRef) that can sometimes fail-fast if the version indexed with the requested ID is less than the specified minIDVersion.
void	seekExact(BytesRef target, TermState otherState) Expert: Seeks a specific position by TermState previously obtained from TermsEnum.termState().
void	seekExact(long ord) Seeks to the specified term by ordinal (position) as previously returned by TermsEnum.ord().
BytesRef	term() Returns current term.
TermState	termState() Expert: Returns the TermsEnums internal state to position the TermsEnum without re-seeking the term dictionary.
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, docs, docs, docsAndPositions, docsAndPositions, postings

Methods inherited from class java.lang.Object

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

Method Detail

seekExact

public boolean seekExact(BytesRef target)
                  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

getVersion

public long getVersion()

Get the version of the currently seek'd term; only valid if we are positioned.

seekExact

public boolean seekExact(BytesRef target,
                long minIDVersion)
                  throws IOException

Optimized version of seekExact(BytesRef) that can sometimes fail-fast if the version indexed with the requested ID is less than the specified minIDVersion. Applications that index a monotonically increasing global version with each document can use this for fast optimistic concurrency.

Throws:

IOException

seekCeil

public TermsEnum.SeekStatus seekCeil(BytesRef target)
                              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

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.

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

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

seekExact

public void seekExact(BytesRef target,
             TermState otherState)

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.

Overrides:

seekExact in class TermsEnum

Parameters:

target - the term the TermState corresponds to

otherState - the TermState

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

Overrides:

termState in class TermsEnum

Throws:

IOException

See Also:

TermState, TermsEnum.seekExact(BytesRef, TermState)

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

toString

public String toString()

Overrides:

toString in class Object