Class AnnotationDocumentIterator
- java.lang.Object
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- it.unimi.di.big.mg4j.search.AbstractDocumentIterator
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- it.unimi.di.big.mg4j.search.AbstractIntervalDocumentIterator
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- it.unimi.di.big.mg4j.search.AnnotationDocumentIterator
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- All Implemented Interfaces:
DocumentIterator
public class AnnotationDocumentIterator extends AbstractIntervalDocumentIterator
A (temporary) document iterator that interpret an index iterator as an annotation and unpacks the position list into an interval list.- Since:
- 5.1.0
- Author:
- Sebastiano Vigna
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Nested Class Summary
Nested Classes Modifier and Type Class Description protected class
AnnotationDocumentIterator.AnnotationIntervalIterator
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Field Summary
Fields Modifier and Type Field Description protected IndexIterator
indexIterator
The underlying iterator.-
Fields inherited from class it.unimi.di.big.mg4j.search.AbstractIntervalDocumentIterator
currentIterators, indices, intervalIterators, soleIndex, soleIntervalIterator, unmodifiableCurrentIterators
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Fields inherited from class it.unimi.di.big.mg4j.search.AbstractDocumentIterator
curr, weight
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Fields inherited from interface it.unimi.di.big.mg4j.search.DocumentIterator
END_OF_LIST
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Constructor Summary
Constructors Modifier Constructor Description protected
AnnotationDocumentIterator(IndexIterator indexIterator)
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Method Summary
Modifier and Type Method Description <T> T
accept(DocumentIteratorVisitor<T> visitor)
Accepts a visitor.<T> T
acceptOnTruePaths(DocumentIteratorVisitor<T> visitor)
Accepts a visitor after a call toDocumentIterator.nextDocument()
, limiting recursion to true paths.void
dispose()
Disposes this document iterator, releasing all resources.static AnnotationDocumentIterator
getInstance(IndexIterator it)
protected IntervalIterator
getIntervalIterator(Index index, int n, boolean allIndexIterators, Object arg)
Creates an interval iterator suitable for thisAbstractIntervalDocumentIterator
.IntervalIterator
intervalIterator()
Returns the interval iterator of this document iterator for single-index queries.IntervalIterator
intervalIterator(Index index)
Returns the interval iterator of this document iterator for the given index.Reference2ReferenceMap<Index,IntervalIterator>
intervalIterators()
Returns an unmodifiable map from indices to interval iterators.boolean
mayHaveNext()
Returns whether there may be a next document, possibly with false positives.long
nextDocument()
Returns the next document provided by this document iterator, orDocumentIterator.END_OF_LIST
if no more documents are available.long
skipTo(long n)
Skips all documents smaller thann
.String
toString()
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Methods inherited from class it.unimi.di.big.mg4j.search.AbstractIntervalDocumentIterator
allIndexIterators, indices, indices
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Methods inherited from class it.unimi.di.big.mg4j.search.AbstractDocumentIterator
document, ensureOnADocument, weight, weight
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Field Detail
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indexIterator
protected final IndexIterator indexIterator
The underlying iterator.
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Constructor Detail
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AnnotationDocumentIterator
protected AnnotationDocumentIterator(IndexIterator indexIterator)
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Method Detail
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getInstance
public static AnnotationDocumentIterator getInstance(IndexIterator it)
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getIntervalIterator
protected IntervalIterator getIntervalIterator(Index index, int n, boolean allIndexIterators, Object arg)
Description copied from class:AbstractIntervalDocumentIterator
Creates an interval iterator suitable for thisAbstractIntervalDocumentIterator
.- Specified by:
getIntervalIterator
in classAbstractIntervalDocumentIterator
- Parameters:
index
- the reference index for the iterator, ornull
.n
- the number of underlying or component iterators.allIndexIterators
- whether all underlying or component iterators are index iterators.arg
- an optional argument.- Returns:
- an interval iterator suitable for this
AbstractIntervalDocumentIterator
.
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nextDocument
public long nextDocument() throws IOException
Description copied from interface:DocumentIterator
Returns the next document provided by this document iterator, orDocumentIterator.END_OF_LIST
if no more documents are available.- Returns:
- the next document, or
DocumentIterator.END_OF_LIST
if no more documents are available. - Throws:
IOException
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mayHaveNext
public boolean mayHaveNext()
Description copied from interface:DocumentIterator
Returns whether there may be a next document, possibly with false positives.- Specified by:
mayHaveNext
in interfaceDocumentIterator
- Overrides:
mayHaveNext
in classAbstractDocumentIterator
- Returns:
- true there may be a next document; false if certainly there is no next document.
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skipTo
public long skipTo(long n) throws IOException
Description copied from interface:DocumentIterator
Skips all documents smaller thann
.Define the current document
k
associated with this document iterator as follows:- -1, if
DocumentIterator.nextDocument()
and this method have never been called; DocumentIterator.END_OF_LIST
, if a call to this method or toDocumentIterator.nextDocument()
returnedDocumentIterator.END_OF_LIST
;- the last value returned by a call to
DocumentIterator.nextDocument()
or this method, otherwise.
If
k
is larger than or equal ton
, then this method does nothing and returnsk
. Otherwise, a call to this method is equivalent towhile( ( k = nextDocument() ) < n ); return k;
Thus, when a result
k
≠DocumentIterator.END_OF_LIST
is returned, the state of this iterator will be exactly the same as after a call toDocumentIterator.nextDocument()
that returnedk
. In particular, the first document larger than or equal ton
(when returned by this method) will not be returned by the next call toDocumentIterator.nextDocument()
.- Parameters:
n
- a document pointer.- Returns:
- a document pointer larger than or equal to
n
if available,DocumentIterator.END_OF_LIST
otherwise. - Throws:
IOException
- -1, if
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intervalIterators
public Reference2ReferenceMap<Index,IntervalIterator> intervalIterators() throws IOException
Description copied from interface:DocumentIterator
Returns an unmodifiable map from indices to interval iterators.After a call to
DocumentIterator.nextDocument()
, this map can be used to retrieve the intervals in the current document. An invocation ofMap.get(java.lang.Object)
on this map with argumentindex
yields the same result asintervalIterator(index)
.- Returns:
- a map from indices to interval iterators over the current document.
- Throws:
IOException
- See Also:
DocumentIterator.intervalIterator(Index)
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intervalIterator
public IntervalIterator intervalIterator() throws IOException
Description copied from interface:DocumentIterator
Returns the interval iterator of this document iterator for single-index queries.This is a commodity method that can be used only for queries built over a single index.
- Returns:
- an interval iterator.
- Throws:
IOException
- See Also:
DocumentIterator.intervalIterator(Index)
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intervalIterator
public IntervalIterator intervalIterator(Index index) throws IOException
Description copied from interface:DocumentIterator
Returns the interval iterator of this document iterator for the given index.After a call to
DocumentIterator.nextDocument()
, this iterator can be used to retrieve the intervals in the current document (the one returned byDocumentIterator.nextDocument()
) for the indexindex
.Note that if all indices have positions, it is guaranteed that at least one index will return an interval. However, for disjunctive queries it cannot be guaranteed that all indices will return an interval.
Indices without positions always return
IntervalIterators.TRUE
. Thus, in presence of indices without positions it is possible that no intervals at all are available.- Parameters:
index
- an index (must be one over which the query was built).- Returns:
- an interval iterator over the current document in
index
. - Throws:
IOException
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dispose
public void dispose() throws IOException
Description copied from interface:DocumentIterator
Disposes this document iterator, releasing all resources.This method should propagate down to the underlying index iterators, where it should release resources such as open files and network connections. If you're doing your own resource tracking and pooling, then you do not need to call this method.
- Throws:
IOException
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accept
public <T> T accept(DocumentIteratorVisitor<T> visitor) throws IOException
Description copied from interface:DocumentIterator
Accepts a visitor.A document iterator is usually structured as composite, with operators as internal nodes and
IndexIterator
s as leaves. This method implements the visitor pattern.- Parameters:
visitor
- the visitor.- Returns:
- an object resulting from the visit, or
null
if the visit was interrupted. - Throws:
IOException
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acceptOnTruePaths
public <T> T acceptOnTruePaths(DocumentIteratorVisitor<T> visitor) throws IOException
Description copied from interface:DocumentIterator
Accepts a visitor after a call toDocumentIterator.nextDocument()
, limiting recursion to true paths.After a call to
DocumentIterator.nextDocument()
, a document iterator is positioned over a document. This call is equivalent toDocumentIterator.accept(DocumentIteratorVisitor)
, but visits only along true paths.We define a true path as a path from the root of the composite that passes only through nodes whose associated subtree is positioned on the same document of the root. Note that
OrDocumentIterator
s detach exhausted iterators from the composite tree, so true paths define the subtree that is causing the current document to satisfy the query represented by this document iterator.For more elaboration, and the main application of this method, see
CounterCollectionVisitor
.- Parameters:
visitor
- the visitor.- Returns:
- an object resulting from the visit, or
null
if the visit was interrupted. - Throws:
IOException
- See Also:
DocumentIterator.accept(DocumentIteratorVisitor)
,CounterCollectionVisitor
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