Class AbstractVisitingPrefixTreeFilter.VisitorTemplate

An abstract class designed to make it easy to implement predicates or other operations on a SpatialPrefixTree indexed field. An instance of this class is not designed to be re-used across AtomicReaderContext instances so simply create a new one for each call to, say a GetDocIdSet(AtomicReaderContext, IBits). The GetDocIdSet() method here starts the work. It first checks that there are indexed terms; if not it quickly returns null. Then it calls Start() so a subclass can set up a return value, like an FixedBitSet. Then it starts the traversal process, calling FindSubCellsToVisit(Cell) which by default finds the top cells that intersect queryShape. If there isn't an indexed cell for a corresponding cell returned for this method then it's short-circuited until it finds one, at which point Visit(Cell) is called. At some depths, of the tree, the algorithm switches to a scanning mode that calls VisitScanned(Cell) for each leaf cell found.

This is a Lucene.NET INTERNAL API, use at your own risk
Inheritance
System.Object
AbstractPrefixTreeFilter.BaseTermsEnumTraverser
AbstractVisitingPrefixTreeFilter.VisitorTemplate
Inherited Members
Namespace: Lucene.Net.Spatial.Prefix
Assembly: Lucene.Net.Spatial.dll
Syntax
public abstract class VisitorTemplate : AbstractPrefixTreeFilter.BaseTermsEnumTraverser

Constructors

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VisitorTemplate(AbstractVisitingPrefixTreeFilter, AtomicReaderContext, IBits, Boolean)

Declaration
public VisitorTemplate(AbstractVisitingPrefixTreeFilter outerInstance, AtomicReaderContext context, IBits acceptDocs, bool hasIndexedLeaves)
Parameters
Type Name Description
AbstractVisitingPrefixTreeFilter outerInstance
AtomicReaderContext context
IBits acceptDocs
System.Boolean hasIndexedLeaves

Fields

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m_hasIndexedLeaves

Declaration
protected readonly bool m_hasIndexedLeaves
Field Value
Type Description
System.Boolean

Methods

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FindSubCellsToVisit(Cell)

Called when doing a divide & conquer to find the next intersecting cells of the query shape that are beneath cell. cell is guaranteed to have an intersection and thus this must return some number of nodes.

Declaration
protected virtual IEnumerator<Cell> FindSubCellsToVisit(Cell cell)
Parameters
Type Name Description
Cell cell
Returns
Type Description
IEnumerator<Cell>
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Finish()

Called last to return the result.

Declaration
protected abstract DocIdSet Finish()
Returns
Type Description
DocIdSet
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GetDocIdSet()

Declaration
public virtual DocIdSet GetDocIdSet()
Returns
Type Description
DocIdSet
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PostSiblings(AbstractVisitingPrefixTreeFilter.VNode)

Declaration
protected virtual void PostSiblings(AbstractVisitingPrefixTreeFilter.VNode vNode)
Parameters
Type Name Description
AbstractVisitingPrefixTreeFilter.VNode vNode
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PreSiblings(AbstractVisitingPrefixTreeFilter.VNode)

Declaration
protected virtual void PreSiblings(AbstractVisitingPrefixTreeFilter.VNode vNode)
Parameters
Type Name Description
AbstractVisitingPrefixTreeFilter.VNode vNode
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Scan(Int32)

Scans (termsEnum.Next()) terms until a term is found that does not start with curVNode's cell. If it finds a leaf cell or a cell at level scanDetailLevel then it calls VisitScanned(Cell).

Declaration
protected virtual void Scan(int scanDetailLevel)
Parameters
Type Name Description
System.Int32 scanDetailLevel
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Start()

Called first to setup things.

Declaration
protected abstract void Start()
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Visit(Cell)

Visit an indexed cell returned from FindSubCellsToVisit(Cell).

Declaration
protected abstract bool Visit(Cell cell)
Parameters
Type Name Description
Cell cell

An intersecting cell.
Returns
Type Description
System.Boolean

true to descend to more levels. It is an error to return true if cell.Level == detailLevel
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VisitLeaf(Cell)

Called after visit() returns true and an indexed leaf cell is found.

Declaration
protected abstract void VisitLeaf(Cell cell)
Parameters
Type Name Description
Cell cell
Remarks

Called after Visit() returns true and an indexed leaf cell is found. An indexed leaf cell means associated documents generally won't be found at further detail levels.

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VisitScanned(Cell)

The cell is either indexed as a leaf or is the last level of detail. It might not even intersect the query shape, so be sure to check for that.

Declaration
protected abstract void VisitScanned(Cell cell)
Parameters
Type Name Description
Cell cell