Class RecursivePrefixTreeStrategy

  • Direct Known Subclasses:

    public class RecursivePrefixTreeStrategy
    extends PrefixTreeStrategy
    A PrefixTreeStrategy which uses AbstractVisitingPrefixTreeQuery. This strategy has support for searching non-point shapes (note: not tested). Even a query shape with distErrPct=0 (fully precise to the grid) should have good performance for typical data, unless there is a lot of indexed data coincident with the shape's edge.
    WARNING: This API is experimental and might change in incompatible ways in the next release.
    • Field Detail

      • prefixGridScanLevel

        protected int prefixGridScanLevel
      • pruneLeafyBranches

        protected boolean pruneLeafyBranches
      • multiOverlappingIndexedShapes

        protected boolean multiOverlappingIndexedShapes
    • Constructor Detail

    • Method Detail

      • getPrefixGridScanLevel

        public int getPrefixGridScanLevel()
      • setPrefixGridScanLevel

        public void setPrefixGridScanLevel​(int prefixGridScanLevel)
        Sets the grid level [1-maxLevels] at which indexed terms are scanned brute-force instead of by grid decomposition. By default this is maxLevels - 4. The final level, maxLevels, is always scanned.
        prefixGridScanLevel - 1 to maxLevels
      • isMultiOverlappingIndexedShapes

        public boolean isMultiOverlappingIndexedShapes()
      • isPruneLeafyBranches

        public boolean isPruneLeafyBranches()
      • setPruneLeafyBranches

        public void setPruneLeafyBranches​(boolean pruneLeafyBranches)
        An optional hint affecting non-point shapes and tree cells implementing CellCanPrune, otherwise ignored.

        It will prune away a complete set sibling leaves to their parent (recursively), resulting in ~20-50% fewer indexed cells, and consequently that much less disk and that much faster indexing. So if it's a quad tree and all 4 sub-cells are there marked as a leaf, then they will be removed (pruned) and the parent is marked as a leaf instead. This occurs recursively on up. Unfortunately, the current implementation will buffer all cells to do this, so consider disabling for high precision (low distErrPct) shapes. (default=true)

      • isGridAlignedShape

        protected boolean isGridAlignedShape​(org.locationtech.spatial4j.shape.Shape shape)
        A quick check of the shape to see if it is perfectly aligned to a grid. Points always are as they are indivisible. It's okay to return false if the shape actually is aligned; this is an optimization hint.
      • makeGridShapeIntersectsQuery

        protected Query makeGridShapeIntersectsQuery​(org.locationtech.spatial4j.shape.Shape gridShape)
        makeQuery(SpatialArgs) specialized for the query being a grid square.