public class DocumentalMergedClusterDocumentIterator extends AbstractDocumentIterator implements DocumentIterator
| Modifier and Type | Field and Description |
|---|---|
protected int |
currentIterator
The current iterator.
|
protected DocumentIterator[] |
documentIterator
The component document iterators.
|
protected long[] |
globalDocumentPointer
The reference array for the queue (containing global document pointers).
|
protected ReferenceSet<Index> |
indices
The set of indices involved in this iterator.
|
protected int |
n
The number of component iterators.
|
protected LongHeapSemiIndirectPriorityQueue |
queue
The queue of document iterator indices (offsets into
documentIterator and usedIndex). |
protected DocumentalClusteringStrategy |
strategy
The cached strategy of the index we refer to.
|
protected int[] |
usedIndex
The indices corresponding to each underlying document iterator.
|
curr, weightEND_OF_LIST| Constructor and Description |
|---|
DocumentalMergedClusterDocumentIterator(DocumentalClusterIndexReader indexReader,
DocumentIterator[] documentIterator,
int[] usedIndex)
Creates a new document iterator for a documental cluster.
|
| Modifier and Type | Method and Description |
|---|---|
<T> T |
accept(DocumentIteratorVisitor<T> visitor)
Accepts a visitor.
|
<T> T |
acceptOnTruePaths(DocumentIteratorVisitor<T> visitor)
Accepts a visitor after a call to
DocumentIterator.nextDocument(),
limiting recursion to true paths. |
void |
dispose()
Disposes this document iterator, releasing all resources.
|
ReferenceSet<Index> |
indices()
Returns the set of indices over which this iterator is built.
|
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.
|
long |
nextDocument()
Returns the next document provided by this document iterator, or
DocumentIterator.END_OF_LIST if no more documents are available. |
long |
skipTo(long p)
Skips all documents smaller than
n. |
document, ensureOnADocument, mayHaveNext, weight, weightclone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, waitdocument, mayHaveNext, weight, weightprotected final DocumentIterator[] documentIterator
protected final int n
protected final int[] usedIndex
protected final DocumentalClusteringStrategy strategy
protected final LongHeapSemiIndirectPriorityQueue queue
documentIterator and usedIndex).protected final long[] globalDocumentPointer
protected final ReferenceSet<Index> indices
protected int currentIterator
public DocumentalMergedClusterDocumentIterator(DocumentalClusterIndexReader indexReader, DocumentIterator[] documentIterator, int[] usedIndex) throws IOException
This constructor uses an array of document iterators that it is not required to be full. This is very useful with rare terms.
indexReader - the underlying index reader.documentIterator - an array of document iterators.usedIndex - an array parallel to documentIterator containing the ordinal numbers
of the indices corresponding to the iterators.IOExceptionpublic IntervalIterator intervalIterator() throws IOException
DocumentIteratorThis is a commodity method that can be used only for queries built over a single index.
intervalIterator in interface DocumentIteratorIOExceptionDocumentIterator.intervalIterator(Index)public IntervalIterator intervalIterator(Index index) throws IOException
DocumentIteratorAfter a call to DocumentIterator.nextDocument(), this iterator
can be used to retrieve the intervals in the current document (the
one returned by DocumentIterator.nextDocument()) for
the index index.
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.
intervalIterator in interface DocumentIteratorindex - an index (must be one over which the query was built).index.IOExceptionpublic Reference2ReferenceMap<Index,IntervalIterator> intervalIterators() throws IOException
DocumentIteratorAfter a call to DocumentIterator.nextDocument(), this map
can be used to retrieve the intervals in the current document. An invocation of Map.get(java.lang.Object)
on this map with argument index yields the same result as
intervalIterator(index).
intervalIterators in interface DocumentIteratorIOExceptionDocumentIterator.intervalIterator(Index)public ReferenceSet<Index> indices()
DocumentIteratorindices in interface DocumentIteratorpublic long skipTo(long p)
throws IOException
DocumentIteratorn.
Define the current document k associated with this document iterator
as follows:
DocumentIterator.nextDocument() and this method have never been called;
DocumentIterator.END_OF_LIST, if a call to this method or to
DocumentIterator.nextDocument() returned DocumentIterator.END_OF_LIST;
DocumentIterator.nextDocument() or this method, otherwise.
If k is larger than or equal to n, then
this method does nothing and returns k. Otherwise, a
call to this method is equivalent to
while( ( 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 to DocumentIterator.nextDocument()
that returned k.
In particular, the first document larger than or equal to n (when returned
by this method) will not be returned by the next call to
DocumentIterator.nextDocument().
skipTo in interface DocumentIteratorp - a document pointer.n if available, DocumentIterator.END_OF_LIST
otherwise.IOExceptionpublic long nextDocument()
throws IOException
DocumentIteratorDocumentIterator.END_OF_LIST if no more documents are available.nextDocument in interface DocumentIteratorDocumentIterator.END_OF_LIST if no more documents are available.IOExceptionpublic <T> T accept(DocumentIteratorVisitor<T> visitor) throws IOException
DocumentIteratorA document iterator is usually structured as composite,
with operators as internal nodes and IndexIterators
as leaves. This method implements the visitor pattern.
accept in interface DocumentIteratorvisitor - the visitor.null if the visit was interrupted.IOExceptionpublic <T> T acceptOnTruePaths(DocumentIteratorVisitor<T> visitor) throws IOException
DocumentIteratorDocumentIterator.nextDocument(),
limiting recursion to true paths.
After a call to DocumentIterator.nextDocument(), a document iterator
is positioned over a document. This call is equivalent to DocumentIterator.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 OrDocumentIterators
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.
acceptOnTruePaths in interface DocumentIteratorvisitor - the visitor.null if the visit was interrupted.IOExceptionDocumentIterator.accept(DocumentIteratorVisitor),
CounterCollectionVisitorpublic void dispose()
throws IOException
DocumentIteratorThis 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.
dispose in interface DocumentIteratorIOException