Class FilteredTermsEnum
- java.lang.Object
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- org.apache.lucene.index.TermsEnum
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- org.apache.lucene.index.FilteredTermsEnum
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- All Implemented Interfaces:
BytesRefIterator
- Direct Known Subclasses:
AutomatonTermsEnum,SingleTermsEnum
public abstract class FilteredTermsEnum extends TermsEnum
Abstract class for enumerating a subset of all terms.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.Please note: Consumers of this enum cannot call
seek(), it is forward only; it throwsUnsupportedOperationExceptionwhen a seeking method is called.
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Nested Class Summary
Nested Classes Modifier and Type Class Description protected static classFilteredTermsEnum.AcceptStatusReturn value, if term should be accepted or the iteration shouldEND.-
Nested classes/interfaces inherited from class org.apache.lucene.index.TermsEnum
TermsEnum.SeekStatus
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Constructor Summary
Constructors Modifier Constructor Description protectedFilteredTermsEnum(TermsEnum tenum)Creates a filteredTermsEnumon a terms enum.protectedFilteredTermsEnum(TermsEnum tenum, boolean startWithSeek)Creates a filteredTermsEnumon a terms enum.
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description protected abstract FilteredTermsEnum.AcceptStatusaccept(BytesRef term)Return if term is accepted, not accepted or the iteration should ended (and possibly seek).AttributeSourceattributes()Returns the related attributes, the returnedAttributeSourceis shared with the delegateTermsEnum.intdocFreq()Returns the number of documents containing the current term.ImpactsEnumimpacts(int flags)Return aImpactsEnum.BytesRefnext()Increments the iteration to the nextBytesRefin the iterator.protected BytesRefnextSeekTerm(BytesRef currentTerm)On the first call tonext()or ifaccept(org.apache.lucene.util.BytesRef)returnsFilteredTermsEnum.AcceptStatus.YES_AND_SEEKorFilteredTermsEnum.AcceptStatus.NO_AND_SEEK, this method will be called to eventually seek the underlying TermsEnum to a new position.longord()Returns ordinal position for current term.PostingsEnumpostings(PostingsEnum reuse, int flags)GetPostingsEnumfor the current term, with control over whether freqs, positions, offsets or payloads are required.TermsEnum.SeekStatusseekCeil(BytesRef term)This enum does not support seeking!voidseekExact(long ord)This enum does not support seeking!booleanseekExact(BytesRef term)This enum does not support seeking!voidseekExact(BytesRef term, TermState state)This enum does not support seeking!protected voidsetInitialSeekTerm(BytesRef term)Use this method to set the initialBytesRefto seek before iterating.BytesRefterm()Returns current term.TermStatetermState()Returns the filtered enums term statelongtotalTermFreq()Returns the total number of occurrences of this term across all documents (the sum of the freq() for each doc that has this term).
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Method Detail
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accept
protected abstract FilteredTermsEnum.AcceptStatus accept(BytesRef term) throws IOException
Return if term is accepted, not accepted or the iteration should ended (and possibly seek).- Throws:
IOException
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setInitialSeekTerm
protected final void setInitialSeekTerm(BytesRef term)
Use this method to set the initialBytesRefto seek before iterating. This is a convenience method for subclasses that do not overridenextSeekTerm(org.apache.lucene.util.BytesRef). If the initial seek term isnull(default), the enum is empty.You can only use this method, if you keep the default implementation of
nextSeekTerm(org.apache.lucene.util.BytesRef).
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nextSeekTerm
protected BytesRef nextSeekTerm(BytesRef currentTerm) throws IOException
On the first call tonext()or ifaccept(org.apache.lucene.util.BytesRef)returnsFilteredTermsEnum.AcceptStatus.YES_AND_SEEKorFilteredTermsEnum.AcceptStatus.NO_AND_SEEK, this method will be called to eventually seek the underlying TermsEnum to a new position. On the first call,currentTermwill benull, later calls will provide the term the underlying enum is positioned at. This method returns per default only one time the initial seek term and thennull, so no repositioning is ever done.Override this method, if you want a more sophisticated TermsEnum, that repositions the iterator during enumeration. If this method always returns
nullthe enum is empty.Please note: This method should always provide a greater term than the last enumerated term, else the behaviour of this enum violates the contract for TermsEnums.
- Throws:
IOException
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attributes
public AttributeSource attributes()
Returns the related attributes, the returnedAttributeSourceis shared with the delegateTermsEnum.- Specified by:
attributesin classTermsEnum
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term
public BytesRef term() throws IOException
Description copied from class:TermsEnumReturns current term. Do not call this when the enum is unpositioned.- Specified by:
termin classTermsEnum- Throws:
IOException
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docFreq
public int docFreq() throws IOExceptionDescription copied from class:TermsEnumReturns the number of documents containing the current term. Do not call this when the enum is unpositioned.TermsEnum.SeekStatus.END.- Specified by:
docFreqin classTermsEnum- Throws:
IOException
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totalTermFreq
public long totalTermFreq() throws IOExceptionDescription copied from class:TermsEnumReturns 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:
totalTermFreqin classTermsEnum- Throws:
IOException
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seekExact
public boolean seekExact(BytesRef term) throws IOException
This enum does not support seeking!- Specified by:
seekExactin classTermsEnum- Returns:
- true if the term is found; return false if the enum is unpositioned.
- Throws:
UnsupportedOperationException- In general, subclasses do not support seeking.IOException
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seekCeil
public TermsEnum.SeekStatus seekCeil(BytesRef term) throws IOException
This enum does not support seeking!- Specified by:
seekCeilin classTermsEnum- Throws:
UnsupportedOperationException- In general, subclasses do not support seeking.IOException
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seekExact
public void seekExact(long ord) throws IOExceptionThis enum does not support seeking!- Specified by:
seekExactin classTermsEnum- Throws:
UnsupportedOperationException- In general, subclasses do not support seeking.IOException
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ord
public long ord() throws IOExceptionDescription copied from class:TermsEnumReturns 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:
ordin classTermsEnum- Throws:
IOException
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postings
public PostingsEnum postings(PostingsEnum reuse, int flags) throws IOException
Description copied from class:TermsEnumGetPostingsEnumfor 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:
postingsin 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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impacts
public ImpactsEnum impacts(int flags) throws IOException
Description copied from class:TermsEnumReturn aImpactsEnum.- Specified by:
impactsin classTermsEnum- Throws:
IOException- See Also:
TermsEnum.postings(PostingsEnum, int)
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seekExact
public void seekExact(BytesRef term, TermState state) throws IOException
This enum does not support seeking!- Specified by:
seekExactin classTermsEnum- Parameters:
term- the term the TermState corresponds tostate- theTermState- Throws:
UnsupportedOperationException- In general, subclasses do not support seeking.IOException
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termState
public TermState termState() throws IOException
Returns the filtered enums term state- Specified by:
termStatein classTermsEnum- Throws:
IOException- See Also:
TermState,TermsEnum.seekExact(BytesRef, TermState)
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next
public BytesRef next() throws IOException
Description copied from interface:BytesRefIteratorIncrements the iteration to the nextBytesRefin the iterator. Returns the resultingBytesRefornullif 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
BytesRefin the iterator ornullif the end of the iterator is reached. - Throws:
IOException- If there is a low-level I/O error.
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