Class FuzzyTermsEnum
- java.lang.Object
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- org.apache.lucene.index.TermsEnum
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- org.apache.lucene.search.FuzzyTermsEnum
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- All Implemented Interfaces:
BytesRefIterator
public final class FuzzyTermsEnum extends TermsEnum
Subclass of TermsEnum for enumerating all terms that are similar to the specified filter term.Term enumerations are always ordered by
BytesRef.compareTo(org.apache.lucene.util.BytesRef)
. Each term in the enumeration is greater than all that precede it.
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Nested Class Summary
Nested Classes Modifier and Type Class Description static interface
FuzzyTermsEnum.LevenshteinAutomataAttribute
reuses compiled automata across different segments, because they are independent of the indexstatic class
FuzzyTermsEnum.LevenshteinAutomataAttributeImpl
Stores compiled automata as a list (indexed by edit distance)-
Nested classes/interfaces inherited from class org.apache.lucene.index.TermsEnum
TermsEnum.SeekStatus
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Constructor Summary
Constructors Constructor Description FuzzyTermsEnum(Terms terms, AttributeSource atts, Term term, int maxEdits, int prefixLength, boolean transpositions)
Constructor for enumeration of all terms from specifiedreader
which share a prefix of lengthprefixLength
withterm
and which have at mostmaxEdits
edits.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description int
docFreq()
Returns the number of documents containing the current term.BytesRef
next()
Increments the iteration to the nextBytesRef
in the iterator.long
ord()
Returns ordinal position for current term.PostingsEnum
postings(PostingsEnum reuse, int flags)
GetPostingsEnum
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 byTermsEnum.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 byTermState
previously obtained fromTermsEnum.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
attributes, postings
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Constructor Detail
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FuzzyTermsEnum
public FuzzyTermsEnum(Terms terms, AttributeSource atts, Term term, int maxEdits, int prefixLength, boolean transpositions) throws IOException
Constructor for enumeration of all terms from specifiedreader
which share a prefix of lengthprefixLength
withterm
and which have at mostmaxEdits
edits.After calling the constructor the enumeration is already pointing to the first valid term if such a term exists.
- Parameters:
terms
- Delivers terms.atts
-AttributeSource
created by the rewrite method ofMultiTermQuery
thats contains information about competitive boosts during rewrite. It is also used to cache DFAs between segment transitions.term
- Pattern term.maxEdits
- Maximum edit distance.prefixLength
- Length of required common prefix. Default value is 0.- Throws:
IOException
- if there is a low-level IO error
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Method Detail
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next
public BytesRef next() throws IOException
Description copied from interface:BytesRefIterator
Increments the iteration to the nextBytesRef
in the iterator. Returns the resultingBytesRef
ornull
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 ornull
if the end of the iterator is reached. - Throws:
IOException
- If there is a low-level I/O error.
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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 classTermsEnum
- Throws:
IOException
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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 classTermsEnum
- Throws:
IOException
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postings
public PostingsEnum postings(PostingsEnum reuse, int flags) throws IOException
Description copied from class:TermsEnum
GetPostingsEnum
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 classTermsEnum
- Parameters:
reuse
- pass a prior PostingsEnum for possible reuseflags
- specifies which optional per-document values you require; seePostingsEnum.FREQS
- Throws:
IOException
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seekExact
public void seekExact(BytesRef term, TermState state) throws IOException
Description copied from class:TermsEnum
Expert: Seeks a specific position byTermState
previously obtained fromTermsEnum.termState()
. Callers should maintain theTermState
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 sameTermsEnum
instance.NOTE: Using this method with an incompatible
TermState
might leave thisTermsEnum
in undefined state. On a segment levelTermState
instances are compatible only iff the source and the targetTermsEnum
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 theAttributeSource
's state.AttributeSource
states must be maintained separately if this method is used.- Overrides:
seekExact
in classTermsEnum
- Parameters:
term
- the term the TermState corresponds tostate
- theTermState
- Throws:
IOException
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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 theAttributeSource
's state. Callers must maintain theAttributeSource
states separately- Overrides:
termState
in classTermsEnum
- Throws:
IOException
- See Also:
TermState
,TermsEnum.seekExact(BytesRef, TermState)
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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 throwUnsupportedOperationException
). Do not call this when the enum is unpositioned.- Specified by:
ord
in classTermsEnum
- Throws:
IOException
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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 thanTermsEnum.seekCeil(org.apache.lucene.util.BytesRef)
.- Overrides:
seekExact
in classTermsEnum
- Throws:
IOException
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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 classTermsEnum
- Throws:
IOException
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seekExact
public void seekExact(long ord) throws IOException
Description copied from class:TermsEnum
Seeks to the specified term by ordinal (position) as previously returned byTermsEnum.ord()
. The target ord may be before or after the current ord, and must be within bounds.- Specified by:
seekExact
in classTermsEnum
- Throws:
IOException
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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 classTermsEnum
- Throws:
IOException
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