org.apache.lucene.codecs.blocktree

Class IntersectTermsEnum

java.lang.Object

org.apache.lucene.index.TermsEnum

org.apache.lucene.codecs.blocktree.IntersectTermsEnum

All Implemented Interfaces:

BytesRefIterator

final class IntersectTermsEnum
extends TermsEnum

This is used to implement efficient Terms.intersect(org.apache.lucene.util.automaton.CompiledAutomaton, org.apache.lucene.util.BytesRef) for block-tree. Note that it cannot seek, except for the initial term on init. It just "nexts" through the intersection of the automaton and the terms. It does not use the terms index at all: on init, it loads the root block, and scans its way to the initial term. Likewise, in next it scans until it finds a term that matches the current automaton transition. If the index has auto-prefix terms (only for DOCS_ONLY fields currently) it will visit these terms when possible and then skip the real terms that auto-prefix term matched.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	IntersectTermsEnum.NoMoreTermsException

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

TermsEnum.SeekStatus

Field Summary

Fields

Modifier and Type	Field and Description
private boolean	allowAutoPrefixTerms
private FST.Arc<BytesRef>[]	arcs
(package private) Automaton	automaton
(package private) BytesRef	commonSuffix
private IntersectTermsEnumFrame	currentFrame
private Transition	currentTransition
(package private) FieldReader	fr
(package private) static Outputs<BytesRef>	fstOutputs
private FST.BytesReader	fstReader
(package private) IndexInput	in
(package private) RunAutomaton	runAutomaton
private BytesRef	savedStartTerm
private Transition	scratchTransition
private int	sinkState Which state in the automaton accepts all possible suffixes.
(package private) IntersectTermsEnumFrame[]	stack
private BytesRef	term
private boolean	useAutoPrefixTerm True if we did return the current auto-prefix term

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

EMPTY

Constructor Summary

Constructors

Constructor and Description
IntersectTermsEnum(FieldReader fr, Automaton automaton, RunAutomaton runAutomaton, BytesRef commonSuffix, BytesRef startTerm, int sinkState)

Method Summary

Modifier and Type	Method and Description
private BytesRef	_next()
private boolean	acceptsSuffixRange(int state, int start, int end) Returns true if, from this state, the automaton accepts any suffix starting with a label between start and end, inclusive.
(package private) static java.lang.String	brToString(BytesRef b)
private void	copyTerm()
int	docFreq() Returns the number of documents containing the current term.
private FST.Arc<BytesRef>	getArc(int ord)
private IntersectTermsEnumFrame	getFrame(int ord)
private int	getState()
BytesRef	next() Increments the iteration to the next BytesRef in the iterator.
long	ord() Returns ordinal position for current term.
private boolean	popPushNext()
PostingsEnum	postings(PostingsEnum reuse, int flags) Get PostingsEnum for the current term, with control over whether freqs, positions, offsets or payloads are required.
private IntersectTermsEnumFrame	pushFrame(int state)
TermsEnum.SeekStatus	seekCeil(BytesRef text) Seeks to the specified term, if it exists, or to the next (ceiling) term.
boolean	seekExact(BytesRef text) 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().
private void	seekToStartTerm(BytesRef target)
private boolean	setSavedStartTerm(BytesRef startTerm)
private boolean	skipPastLastAutoPrefixTerm()
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, seekExact

Methods inherited from class java.lang.Object

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

Field Detail

in

final IndexInput in

fstOutputs

static final Outputs<BytesRef> fstOutputs

stack

IntersectTermsEnumFrame[] stack

arcs

private FST.Arc<BytesRef>[] arcs

runAutomaton

final RunAutomaton runAutomaton

automaton

final Automaton automaton

commonSuffix

final BytesRef commonSuffix

currentFrame

private IntersectTermsEnumFrame currentFrame

currentTransition

private Transition currentTransition

term

private final BytesRef term

fstReader

private final FST.BytesReader fstReader

allowAutoPrefixTerms

private final boolean allowAutoPrefixTerms

fr

final FieldReader fr

sinkState

private final int sinkState

Which state in the automaton accepts all possible suffixes.

savedStartTerm

private BytesRef savedStartTerm

useAutoPrefixTerm

private boolean useAutoPrefixTerm

True if we did return the current auto-prefix term

scratchTransition

private final Transition scratchTransition

Constructor Detail

IntersectTermsEnum

public IntersectTermsEnum(FieldReader fr,
                          Automaton automaton,
                          RunAutomaton runAutomaton,
                          BytesRef commonSuffix,
                          BytesRef startTerm,
                          int sinkState)
                   throws java.io.IOException

Throws:

java.io.IOException

Method Detail

setSavedStartTerm

private boolean setSavedStartTerm(BytesRef startTerm)

termState

public TermState termState()
                    throws java.io.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:

java.io.IOException

See Also:

TermState, TermsEnum.seekExact(BytesRef, TermState)

getFrame

private IntersectTermsEnumFrame getFrame(int ord)
                                  throws java.io.IOException

Throws:

java.io.IOException

getArc

private FST.Arc<BytesRef> getArc(int ord)

pushFrame

private IntersectTermsEnumFrame pushFrame(int state)
                                   throws java.io.IOException

Throws:

java.io.IOException

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 java.io.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:

java.io.IOException

totalTermFreq

public long totalTermFreq()
                   throws java.io.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:

java.io.IOException

postings

public PostingsEnum postings(PostingsEnum reuse,
                             int flags)
                      throws java.io.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:

java.io.IOException

getState

private int getState()

seekToStartTerm

private void seekToStartTerm(BytesRef target)
                      throws java.io.IOException

Throws:

java.io.IOException

popPushNext

private boolean popPushNext()
                     throws java.io.IOException

Throws:

java.io.IOException

skipPastLastAutoPrefixTerm

private boolean skipPastLastAutoPrefixTerm()
                                    throws java.io.IOException

Throws:

java.io.IOException

next

public BytesRef next()
              throws java.io.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:

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

_next

private BytesRef _next()
                throws java.io.IOException

Throws:

java.io.IOException

acceptsSuffixRange

private boolean acceptsSuffixRange(int state,
                                   int start,
                                   int end)

Returns true if, from this state, the automaton accepts any suffix starting with a label between start and end, inclusive. We just look for a transition, matching this range, to the sink state.

brToString

static java.lang.String brToString(BytesRef b)

copyTerm

private void copyTerm()

seekExact

public boolean seekExact(BytesRef text)

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

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

seekCeil

public TermsEnum.SeekStatus seekCeil(BytesRef text)

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