Package it.unimi.di.big.mg4j.search

Class OrDocumentIterator

java.lang.Object

it.unimi.di.big.mg4j.search.AbstractDocumentIterator

it.unimi.di.big.mg4j.search.AbstractIntervalDocumentIterator

it.unimi.di.big.mg4j.search.AbstractCompositeDocumentIterator

it.unimi.di.big.mg4j.search.AbstractUnionDocumentIterator

it.unimi.di.big.mg4j.search.OrDocumentIterator

All Implemented Interfaces:

DocumentIterator

public class OrDocumentIterator
extends AbstractUnionDocumentIterator
implements DocumentIterator

An iterator on documents that returns the OR of a number of document iterators.

This class adds to AbstractUnionDocumentIterator an interval iterator generating the OR of the intervals returned for each of the documents involved.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected class	OrDocumentIterator.OrIndexIntervalIterator
protected class	OrDocumentIterator.OrIntervalIterator

Nested classes/interfaces inherited from class it.unimi.di.big.mg4j.search.AbstractUnionDocumentIterator

AbstractUnionDocumentIterator.IntHeapSemiIndirectPriorityQueue, AbstractUnionDocumentIterator.LongHeapSemiIndirectPriorityQueue

Nested classes/interfaces inherited from class it.unimi.di.big.mg4j.search.AbstractCompositeDocumentIterator

AbstractCompositeDocumentIterator.AbstractCompositeIndexIntervalIterator, AbstractCompositeDocumentIterator.AbstractCompositeIntervalIterator

Field Summary

Fields inherited from class it.unimi.di.big.mg4j.search.AbstractUnionDocumentIterator

front, frontSize, queue, refArray

Fields inherited from class it.unimi.di.big.mg4j.search.AbstractCompositeDocumentIterator

documentIterator, indexIterator, indexIteratorsWithoutPositions, n

Fields inherited from class it.unimi.di.big.mg4j.search.AbstractIntervalDocumentIterator

currentIterators, indices, intervalIterators, soleIndex, soleIntervalIterator, unmodifiableCurrentIterators

Fields inherited from class it.unimi.di.big.mg4j.search.AbstractDocumentIterator

curr, weight

Fields inherited from interface it.unimi.di.big.mg4j.search.DocumentIterator

END_OF_LIST

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	OrDocumentIterator(DocumentIterator... documentIterator)

Method Summary

Modifier and Type	Method	Description
void	dispose()	Disposes this document iterator, releasing all resources.
static DocumentIterator	getInstance(Index index, DocumentIterator... documentIterator)	Returns a document iterator that computes the OR of the given array of iterators.
static DocumentIterator	getInstance(DocumentIterator... documentIterator)	Returns a document iterator that computes the OR of the given nonzero-length array of iterators.
protected IntervalIterator	getIntervalIterator(Index index, int n, boolean allIndexIterators, Object unused)	Creates an interval iterator suitable for this AbstractIntervalDocumentIterator.
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.

Methods inherited from class it.unimi.di.big.mg4j.search.AbstractUnionDocumentIterator

acceptOnTruePaths, computeFront, intervalIterators, nextDocument, skipTo

Methods inherited from class it.unimi.di.big.mg4j.search.AbstractCompositeDocumentIterator

accept, toString

Methods inherited from class it.unimi.di.big.mg4j.search.AbstractIntervalDocumentIterator

allIndexIterators, indices, indices

Methods inherited from class it.unimi.di.big.mg4j.search.AbstractDocumentIterator

document, ensureOnADocument, mayHaveNext, weight, weight

Methods inherited from class java.lang.Object

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

Methods inherited from interface it.unimi.di.big.mg4j.search.DocumentIterator

accept, acceptOnTruePaths, document, indices, intervalIterators, mayHaveNext, nextDocument, skipTo, weight, weight

Constructor Detail

OrDocumentIterator

protected OrDocumentIterator(DocumentIterator... documentIterator)

Method Detail

getInstance

public static DocumentIterator getInstance(Index index,
                                           DocumentIterator... documentIterator)

Returns a document iterator that computes the OR of the given array of iterators.

Note that the special case of the empty and of the singleton arrays are handled efficiently.

Parameters:

index - the default index; relevant only if documentIterator has zero length.

documentIterator - the iterators to be joined.

Returns:

a document iterator that computes the OR of documentIterator.

getInstance

public static DocumentIterator getInstance(DocumentIterator... documentIterator)

Returns a document iterator that computes the OR of the given nonzero-length array of iterators.

Note that the special case of the singleton array is handled efficiently.

Parameters:

documentIterator - the iterators to be joined.

Returns:

a document iterator that computes the OR of documentIterator.

getIntervalIterator

protected IntervalIterator getIntervalIterator(Index index,
                                               int n,
                                               boolean allIndexIterators,
                                               Object unused)

Description copied from class: AbstractIntervalDocumentIterator

Creates an interval iterator suitable for this AbstractIntervalDocumentIterator.

Specified by:

getIntervalIterator in class AbstractIntervalDocumentIterator

Parameters:

index - the reference index for the iterator, or null.

n - the number of underlying or component iterators.

allIndexIterators - whether all underlying or component iterators are index iterators.

unused - an optional argument.

Returns:

an interval iterator suitable for this AbstractIntervalDocumentIterator.

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.

Specified by:

intervalIterator in interface DocumentIterator

Returns:

an interval iterator.

Throws:

IOException

See Also:

DocumentIterator.intervalIterator(Index)

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 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.

Specified by:

intervalIterator in interface DocumentIterator

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

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.

Specified by:

dispose in interface DocumentIterator

Overrides:

dispose in class AbstractCompositeDocumentIterator

Throws:

IOException