org.apache.lucene.spatial.prefix
Class AbstractVisitingPrefixTreeFilter.VisitorTemplate

java.lang.Object
  org.apache.lucene.spatial.prefix.AbstractPrefixTreeFilter.BaseTermsEnumTraverser
      org.apache.lucene.spatial.prefix.AbstractVisitingPrefixTreeFilter.VisitorTemplate

Enclosing class:

AbstractVisitingPrefixTreeFilter

public abstract class AbstractVisitingPrefixTreeFilter.VisitorTemplate
extends AbstractPrefixTreeFilter.BaseTermsEnumTraverser

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 Filter.getDocIdSet(org.apache.lucene.index.AtomicReaderContext, org.apache.lucene.util.Bits). 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 OpenBitSet. Then it starts the traversal process, calling findSubCellsToVisit(org.apache.lucene.spatial.prefix.tree.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(org.apache.lucene.spatial.prefix.tree.Cell) is called. At some depths, of the tree, the algorithm switches to a scanning mode that finds calls visitScanned(org.apache.lucene.spatial.prefix.tree.Cell) for each leaf cell found.

NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.

Field Summary

protected boolean

hasIndexedLeaves

Fields inherited from class org.apache.lucene.spatial.prefix.AbstractPrefixTreeFilter.BaseTermsEnumTraverser

acceptDocs, context, docsEnum, maxDoc, termsEnum

Constructor Summary

AbstractVisitingPrefixTreeFilter.VisitorTemplate(AtomicReaderContext context, Bits acceptDocs, boolean hasIndexedLeaves)

Method Summary

protected Iterator<Cell>	findSubCellsToVisit(Cell cell) Called when doing a divide & conquer to find the next intersecting cells of the query shape that are beneath cell.
protected abstract DocIdSet	finish() Called last to return the result.
DocIdSet	getDocIdSet()
protected void	postSiblings(AbstractVisitingPrefixTreeFilter.VNode vNode)
protected void	preSiblings(AbstractVisitingPrefixTreeFilter.VNode vNode)
protected void	scan(int scanDetailLevel) Scans (termsEnum.next()) terms until a term is found that does not start with curVNode's cell.
protected abstract void	start() Called first to setup things.
protected abstract boolean	visit(Cell cell) Visit an indexed cell returned from findSubCellsToVisit(org.apache.lucene.spatial.prefix.tree.Cell).
protected abstract void	visitLeaf(Cell cell) Called after visit() returns true and an indexed leaf cell is found.
protected abstract void	visitScanned(Cell cell) The cell is either indexed as a leaf or is the last level of detail.

Methods inherited from class org.apache.lucene.spatial.prefix.AbstractPrefixTreeFilter.BaseTermsEnumTraverser

collectDocs

Methods inherited from class java.lang.Object

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

Field Detail

hasIndexedLeaves

protected final boolean hasIndexedLeaves

Constructor Detail

AbstractVisitingPrefixTreeFilter.VisitorTemplate

public AbstractVisitingPrefixTreeFilter.VisitorTemplate(AtomicReaderContext context,
                                                        Bits acceptDocs,
                                                        boolean hasIndexedLeaves)
                                                 throws IOException

Throws:

IOException

Method Detail

getDocIdSet

public DocIdSet getDocIdSet()
                     throws IOException

Throws:

IOException

findSubCellsToVisit

protected Iterator<Cell> findSubCellsToVisit(Cell 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.

scan

protected void scan(int scanDetailLevel)
             throws IOException

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(org.apache.lucene.spatial.prefix.tree.Cell).

Throws:

IOException

start

protected abstract void start()
                       throws IOException

Called first to setup things.

Throws:

IOException

finish

protected abstract DocIdSet finish()
                            throws IOException

Called last to return the result.

Throws:

IOException

visit

protected abstract boolean visit(Cell cell)
                          throws IOException

Visit an indexed cell returned from findSubCellsToVisit(org.apache.lucene.spatial.prefix.tree.Cell).

Parameters:

cell - An intersecting cell.

Returns:

true to descend to more levels. It is an error to return true if cell.level == detailLevel

Throws:

IOException

visitLeaf

protected abstract void visitLeaf(Cell cell)
                           throws IOException

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.

Throws:

IOException

visitScanned

protected abstract void visitScanned(Cell cell)
                              throws IOException

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.

Throws:

IOException

preSiblings

protected void preSiblings(AbstractVisitingPrefixTreeFilter.VNode vNode)
                    throws IOException

Throws:

IOException

postSiblings

protected void postSiblings(AbstractVisitingPrefixTreeFilter.VNode vNode)
                     throws IOException

Throws:

IOException