/*
 * 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.util;

import org.locationtech.spatial4j.shape.Shape;
import org.apache.lucene.index.*;
import org.apache.lucene.search.DocIdSetIterator;
import org.apache.lucene.util.BytesRef;

import java.io.IOException;
import java.util.WeakHashMap;
import java.util.logging.Logger;

Provides access to a ShapeFieldCache for a given LeafReader. If a Cache does not exist for the Reader, then it is built by iterating over the all terms for a given field, reconstructing the Shape from them, and adding them to the Cache.
@lucene.internal
/** * Provides access to a {@link ShapeFieldCache} for a given {@link org.apache.lucene.index.LeafReader}. * * If a Cache does not exist for the Reader, then it is built by iterating over * the all terms for a given field, reconstructing the Shape from them, and adding * them to the Cache. * * @lucene.internal */
public abstract class ShapeFieldCacheProvider<T extends Shape> { private Logger log = Logger.getLogger(getClass().getName()); // it may be a List<T> or T WeakHashMap<IndexReader, ShapeFieldCache<T>> sidx = new WeakHashMap<>(); protected final int defaultSize; protected final String shapeField; public ShapeFieldCacheProvider(String shapeField, int defaultSize) { this.shapeField = shapeField; this.defaultSize = defaultSize; } protected abstract T readShape( BytesRef term ); public synchronized ShapeFieldCache<T> getCache(LeafReader reader) throws IOException { ShapeFieldCache<T> idx = sidx.get(reader); if (idx != null) { return idx; } long startTime = System.currentTimeMillis(); log.fine("Building Cache [" + reader.maxDoc() + "]"); idx = new ShapeFieldCache<>(reader.maxDoc(),defaultSize); int count = 0; PostingsEnum docs = null; Terms terms = reader.terms(shapeField); if (terms != null) { TermsEnum te = terms.iterator(); BytesRef term = te.next(); while (term != null) { T shape = readShape(term); if( shape != null ) { docs = te.postings(docs, PostingsEnum.NONE); Integer docid = docs.nextDoc(); while (docid != DocIdSetIterator.NO_MORE_DOCS) { idx.add( docid, shape ); docid = docs.nextDoc(); count++; } } term = te.next(); } } sidx.put(reader, idx); long elapsed = System.currentTimeMillis() - startTime; log.fine("Cached: [" + count + " in " + elapsed + "ms] " + idx); return idx; } }