Java tutorial
/* * 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.Map; import java.util.SortedMap; import java.util.TreeMap; import org.apache.lucene.index.IndexReaderContext; import org.apache.lucene.search.DoubleValuesSource; import org.apache.lucene.spatial.prefix.tree.Cell; import org.apache.lucene.spatial.prefix.tree.NumberRangePrefixTree; import org.apache.lucene.util.Bits; import org.locationtech.spatial4j.shape.Point; import org.locationtech.spatial4j.shape.Shape; 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 boolean isPointShape(Shape shape) { if (shape instanceof NumberRangePrefixTree.UnitNRShape) { return ((NumberRangePrefixTree.UnitNRShape) shape).getLevel() == grid.getMaxLevels(); } else { return false; } } @Override protected boolean isGridAlignedShape(Shape shape) { // any UnitNRShape other than the world is a single cell/term if (shape instanceof NumberRangePrefixTree.UnitNRShape) { return ((NumberRangePrefixTree.UnitNRShape) shape).getLevel() > 0; } else { return false; } } /** Unsupported. */ @Override public DoubleValuesSource 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=").append(detailLevel).append(" topLeaves=").append(topLeaves) .append(" parentCount=").append(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()).append(" leafCount=").append(pVal.parentLeaves); if (pVal.childCounts != null) { buf.append(' ').append(Arrays.toString(pVal.childCounts)); } } return buf.toString(); } } }