package org.apache.lucene.facet.search.cache;
import java.io.IOException;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.facet.index.params.CategoryListParams;
import org.apache.lucene.facet.index.params.FacetIndexingParams;
import org.apache.lucene.facet.search.CategoryListIterator;
import org.apache.lucene.facet.taxonomy.TaxonomyReader;
import org.apache.lucene.util.collections.IntArray;
/*
* 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.
*/
/**
* Category list data maintained in RAM.
* <p>
* Speeds up facets accumulation when more RAM is available.
* <p>
* Note that this will consume more memory: one int (4 bytes) for each category
* of each document.
* <p>
* Note: at the moment this class is insensitive to updates of the index, and,
* in particular, does not make use of Lucene's ability to refresh a single
* segment.
* <p>
* See {@link CategoryListCache#register(CategoryListParams, CategoryListData)}
* and
* {@link CategoryListCache#loadAndRegister(CategoryListParams, IndexReader, TaxonomyReader, FacetIndexingParams)}.
*
* @lucene.experimental
*/
public class CategoryListData {
// TODO (Facet): experiment with different orders - p-d-c vs. current d-p-c.
private transient volatile int[][][] docPartitionCategories;
/**
* Empty constructor for extensions with modified computation of the data.
*/
protected CategoryListData() {
}
/**
* Compute category list data for caching for faster iteration.
*/
CategoryListData(IndexReader reader, TaxonomyReader taxo,
FacetIndexingParams iparams, CategoryListParams clp) throws IOException {
final int maxDoc = reader.maxDoc();
int[][][]dpf = new int[maxDoc][][];
int numPartitions = (int)Math.ceil(taxo.getSize()/(double)iparams.getPartitionSize());
IntArray docCategories = new IntArray();
for (int part=0; part<numPartitions; part++) {
CategoryListIterator cli = clp.createCategoryListIterator(reader, part);
if (cli.init()) {
for (int doc=0; doc<maxDoc; doc++) {
if (cli.skipTo(doc)) {
docCategories.clear(false);
if (dpf[doc]==null) {
dpf[doc] = new int[numPartitions][];
}
long category;
while ((category = cli.nextCategory()) <= Integer.MAX_VALUE) {
docCategories.addToArray((int)category);
}
final int size = docCategories.size();
dpf[doc][part] = new int[size];
for (int i=0; i<size; i++) {
dpf[doc][part][i] = docCategories.get(i);
}
}
}
}
}
docPartitionCategories = dpf;
}
/**
* Iterate on the category list data for the specified partition.
*/
public CategoryListIterator iterator(int partition) throws IOException {
return new RAMCategoryListIterator(partition, docPartitionCategories);
}
/**
* Internal: category list iterator over uncompressed category info in RAM
*/
private static class RAMCategoryListIterator implements CategoryListIterator {
private final int part;
private final int[][][] dpc;
private int currDoc = -1;
private int nextCategoryIndex = -1;
RAMCategoryListIterator(int part, int[][][] docPartitionCategories) {
this.part = part;
dpc = docPartitionCategories;
}
public boolean init() throws IOException {
return dpc!=null && dpc.length>part;
}
public long nextCategory() throws IOException {
if (nextCategoryIndex >= dpc[currDoc][part].length) {
return 1L+Integer.MAX_VALUE;
}
return dpc[currDoc][part][nextCategoryIndex++];
}
public boolean skipTo(int docId) throws IOException {
final boolean res = dpc.length>docId && dpc[docId]!=null && dpc[docId][part]!=null;
if (res) {
currDoc = docId;
nextCategoryIndex = 0;
}
return res;
}
}
}