/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.lucene.spatial.prefix;
import java.io.IOException;
import java.util.Arrays;
import java.util.Iterator;
import java.util.Map;
import java.util.SortedMap;
import java.util.TreeMap;
import org.locationtech.spatial4j.shape.Point;
import org.locationtech.spatial4j.shape.Shape;
import org.apache.lucene.index.IndexReaderContext;
import org.apache.lucene.queries.function.ValueSource;
import org.apache.lucene.spatial.prefix.tree.Cell;
import org.apache.lucene.spatial.prefix.tree.NumberRangePrefixTree;
import org.apache.lucene.util.Bits;
import static org.apache.lucene.spatial.prefix.tree.NumberRangePrefixTree.UnitNRShape;
/** A PrefixTree based on Number/Date ranges. This isn't very "spatial" on the surface (to the user) but
* it's implemented using spatial so that's why it's here extending a SpatialStrategy. When using this class, you will
* use various utility methods on the prefix tree implementation to convert objects/strings to/from shapes.
*
* To use with dates, pass in {@link org.apache.lucene.spatial.prefix.tree.DateRangePrefixTree}.
*
* @lucene.experimental
*/
public class NumberRangePrefixTreeStrategy extends RecursivePrefixTreeStrategy {
public NumberRangePrefixTreeStrategy(NumberRangePrefixTree prefixTree, String fieldName) {
super(prefixTree, fieldName);
setPruneLeafyBranches(false);
setPrefixGridScanLevel(prefixTree.getMaxLevels()-2);//user might want to change, however
setPointsOnly(false);
setDistErrPct(0);
}
@Override
public NumberRangePrefixTree getGrid() {
return (NumberRangePrefixTree) super.getGrid();
}
@Override
protected Iterator<Cell> createCellIteratorToIndex(Shape shape, int detailLevel, Iterator<Cell> reuse) {
//levels doesn't actually matter; NumberRange based Shapes have their own "level".
return super.createCellIteratorToIndex(shape, grid.getMaxLevels(), reuse);
}
/** Unsupported. */
@Override
public ValueSource makeDistanceValueSource(Point queryPoint, double multiplier) {
throw new UnsupportedOperationException();
}
/** Calculates facets between {@code start} and {@code end} to a detail level one greater than that provided by the
* arguments. For example providing March to October of 2014 would return facets to the day level of those months.
* This is just a convenience method.
* @see #calcFacets(IndexReaderContext, Bits, Shape, int)
*/
public Facets calcFacets(IndexReaderContext context, Bits topAcceptDocs, UnitNRShape start, UnitNRShape end)
throws IOException {
Shape facetRange = getGrid().toRangeShape(start, end);
int detailLevel = Math.max(start.getLevel(), end.getLevel()) + 1;
return calcFacets(context, topAcceptDocs, facetRange, detailLevel);
}
/**
* Calculates facets (aggregated counts) given a range shape (start-end span) and a level, which specifies the detail.
* To get the level of an existing shape, say a Calendar, call
* {@link org.apache.lucene.spatial.prefix.tree.NumberRangePrefixTree#toUnitShape(Object)} then call
* {@link org.apache.lucene.spatial.prefix.tree.NumberRangePrefixTree.UnitNRShape#getLevel()}.
* Facet computation is implemented by navigating the underlying indexed terms efficiently.
*/
public Facets calcFacets(IndexReaderContext context, Bits topAcceptDocs, Shape facetRange, final int level)
throws IOException {
final Facets facets = new Facets(level);
PrefixTreeFacetCounter.compute(this, context, topAcceptDocs, facetRange, level,
new PrefixTreeFacetCounter.FacetVisitor() {
Facets.FacetParentVal parentFacet;
UnitNRShape parentShape;
@Override
public void visit(Cell cell, int count) {
if (cell.getLevel() < level - 1) {//some ancestor of parent facet level, direct or distant
parentFacet = null;//reset
parentShape = null;//reset
facets.topLeaves += count;
} else if (cell.getLevel() == level - 1) {//parent
//set up FacetParentVal
setupParent((UnitNRShape) cell.getShape());
parentFacet.parentLeaves += count;
} else {//at facet level
UnitNRShape unitShape = (UnitNRShape) cell.getShape();
UnitNRShape unitShapeParent = unitShape.getShapeAtLevel(unitShape.getLevel() - 1);
if (parentFacet == null || !parentShape.equals(unitShapeParent)) {
setupParent(unitShapeParent);
}
//lazy init childCounts
if (parentFacet.childCounts == null) {
parentFacet.childCounts = new int[parentFacet.childCountsLen];
}
parentFacet.childCounts[unitShape.getValAtLevel(cell.getLevel())] += count;
}
}
private void setupParent(UnitNRShape unitShape) {
parentShape = unitShape.clone();
//Look for existing parentFacet (from previous segment), or create anew if needed
parentFacet = facets.parents.get(parentShape);
if (parentFacet == null) {//didn't find one; make a new one
parentFacet = new Facets.FacetParentVal();
parentFacet.childCountsLen = getGrid().getNumSubCells(parentShape);
facets.parents.put(parentShape, parentFacet);
}
}
});
return facets;
}
/** Facet response information */
public static class Facets {
//TODO consider a variable-level structure -- more general purpose.
public Facets(int detailLevel) {
this.detailLevel = detailLevel;
}
/** The bottom-most detail-level counted, as requested. */
public final int detailLevel;
/**
* The count of documents with ranges that completely spanned the parents of the detail level. In more technical
* terms, this is the count of leaf cells 2 up and higher from the bottom. Usually you only care about counts at
* detailLevel, and so you will add this number to all other counts below, including to omitted/implied children
* counts of 0. If there are no indexed ranges (just instances, i.e. fully specified dates) then this value will
* always be 0.
*/
public int topLeaves;
/** Holds all the {@link FacetParentVal} instances in order of the key. This is sparse; there won't be an
* instance if it's count and children are all 0. The keys are {@link org.apache.lucene.spatial.prefix.tree.NumberRangePrefixTree.UnitNRShape} shapes, which can be
* converted back to the original Object (i.e. a Calendar) via
* {@link NumberRangePrefixTree#toObject(org.apache.lucene.spatial.prefix.tree.NumberRangePrefixTree.UnitNRShape)}. */
public final SortedMap<UnitNRShape,FacetParentVal> parents = new TreeMap<>();
/** Holds a block of detailLevel counts aggregated to their parent level. */
public static class FacetParentVal {
/** The count of ranges that span all of the childCounts. In more technical terms, this is the number of leaf
* cells found at this parent. Treat this like {@link Facets#topLeaves}. */
public int parentLeaves;
/** The length of {@link #childCounts}. If childCounts is not null then this is childCounts.length, otherwise it
* says how long it would have been if it weren't null. */
public int childCountsLen;
/** The detail level counts. It will be null if there are none, and thus they are assumed 0. Most apps, when
* presenting the information, will add {@link #topLeaves} and {@link #parentLeaves} to each count. */
public int[] childCounts;
//assert childCountsLen == childCounts.length
}
@Override
public String toString() {
StringBuilder buf = new StringBuilder(2048);
buf.append("Facets: level=" + detailLevel + " topLeaves=" + topLeaves + " parentCount=" + parents.size());
for (Map.Entry<UnitNRShape, FacetParentVal> entry : parents.entrySet()) {
buf.append('\n');
if (buf.length() > 1000) {
buf.append("...");
break;
}
final FacetParentVal pVal = entry.getValue();
buf.append(' ').append(entry.getKey()+" leafCount=" + pVal.parentLeaves);
if (pVal.childCounts != null) {
buf.append(' ').append(Arrays.toString(pVal.childCounts));
}
}
return buf.toString();
}
}
}