package org.apache.lucene.facet;
/*
* 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.
*/
import java.io.IOException;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.Term;
import org.apache.lucene.search.BooleanClause.Occur;
import org.apache.lucene.search.BooleanClause;
import org.apache.lucene.search.BooleanQuery;
import org.apache.lucene.search.ConstantScoreQuery;
import org.apache.lucene.search.Filter;
import org.apache.lucene.search.FilteredQuery;
import org.apache.lucene.search.MatchAllDocsQuery;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.TermQuery;
/**
* A {@link Query} for drill-down over facet categories. You
* should call {@link #add(String, String...)} for every group of categories you
* want to drill-down over.
* <p>
* <b>NOTE:</b> if you choose to create your own {@link Query} by calling
* {@link #term}, it is recommended to wrap it with {@link ConstantScoreQuery}
* and set the {@link ConstantScoreQuery#setBoost(float) boost} to {@code 0.0f},
* so that it does not affect the scores of the documents.
*
* @lucene.experimental
*/
public final class DrillDownQuery extends Query {
/** Creates a drill-down term. */
public static Term term(String field, String dim, String... path) {
return new Term(field, FacetsConfig.pathToString(dim, path));
}
private final FacetsConfig config;
private final BooleanQuery query;
private final Map<String,Integer> drillDownDims = new LinkedHashMap<String,Integer>();
/** Used by clone() */
DrillDownQuery(FacetsConfig config, BooleanQuery query, Map<String,Integer> drillDownDims) {
this.query = query.clone();
this.drillDownDims.putAll(drillDownDims);
this.config = config;
}
/** Used by DrillSideways */
DrillDownQuery(FacetsConfig config, Filter filter, DrillDownQuery other) {
query = new BooleanQuery(true); // disable coord
BooleanClause[] clauses = other.query.getClauses();
if (clauses.length == other.drillDownDims.size()) {
throw new IllegalArgumentException("cannot apply filter unless baseQuery isn't null; pass ConstantScoreQuery instead");
}
assert clauses.length == 1+other.drillDownDims.size(): clauses.length + " vs " + (1+other.drillDownDims.size());
drillDownDims.putAll(other.drillDownDims);
query.add(new FilteredQuery(clauses[0].getQuery(), filter), Occur.MUST);
for(int i=1;i<clauses.length;i++) {
query.add(clauses[i].getQuery(), Occur.MUST);
}
this.config = config;
}
/** Used by DrillSideways */
DrillDownQuery(FacetsConfig config, Query baseQuery, List<Query> clauses, Map<String,Integer> drillDownDims) {
query = new BooleanQuery(true);
if (baseQuery != null) {
query.add(baseQuery, Occur.MUST);
}
for(Query clause : clauses) {
query.add(clause, Occur.MUST);
}
this.drillDownDims.putAll(drillDownDims);
this.config = config;
}
/** Creates a new {@code DrillDownQuery} without a base query,
* to perform a pure browsing query (equivalent to using
* {@link MatchAllDocsQuery} as base). */
public DrillDownQuery(FacetsConfig config) {
this(config, null);
}
/** Creates a new {@code DrillDownQuery} over the given base query. Can be
* {@code null}, in which case the result {@link Query} from
* {@link #rewrite(IndexReader)} will be a pure browsing query, filtering on
* the added categories only. */
public DrillDownQuery(FacetsConfig config, Query baseQuery) {
query = new BooleanQuery(true); // disable coord
if (baseQuery != null) {
query.add(baseQuery, Occur.MUST);
}
this.config = config;
}
/** Merges (ORs) a new path into an existing AND'd
* clause. */
private void merge(String dim, String[] path) {
int index = drillDownDims.get(dim);
if (query.getClauses().length == drillDownDims.size()+1) {
index++;
}
ConstantScoreQuery q = (ConstantScoreQuery) query.clauses().get(index).getQuery();
if ((q.getQuery() instanceof BooleanQuery) == false) {
// App called .add(dim, customQuery) and then tried to
// merge a facet label in:
throw new RuntimeException("cannot merge with custom Query");
}
String indexedField = config.getDimConfig(dim).indexFieldName;
BooleanQuery bq = (BooleanQuery) q.getQuery();
bq.add(new TermQuery(term(indexedField, dim, path)), Occur.SHOULD);
}
/** Adds one dimension of drill downs; if you pass the same
* dimension more than once it is OR'd with the previous
* cofnstraints on that dimension, and all dimensions are
* AND'd against each other and the base query. */
public void add(String dim, String... path) {
if (drillDownDims.containsKey(dim)) {
merge(dim, path);
return;
}
String indexedField = config.getDimConfig(dim).indexFieldName;
BooleanQuery bq = new BooleanQuery(true); // disable coord
bq.add(new TermQuery(term(indexedField, dim, path)), Occur.SHOULD);
add(dim, bq);
}
/** Expert: add a custom drill-down subQuery. Use this
* when you have a separate way to drill-down on the
* dimension than the indexed facet ordinals. */
public void add(String dim, Query subQuery) {
if (drillDownDims.containsKey(dim)) {
throw new IllegalArgumentException("dimension \"" + dim + "\" already has a drill-down");
}
// TODO: we should use FilteredQuery?
// So scores of the drill-down query don't have an
// effect:
final ConstantScoreQuery drillDownQuery = new ConstantScoreQuery(subQuery);
drillDownQuery.setBoost(0.0f);
query.add(drillDownQuery, Occur.MUST);
drillDownDims.put(dim, drillDownDims.size());
}
/** Expert: add a custom drill-down Filter, e.g. when
* drilling down after range faceting. */
public void add(String dim, Filter subFilter) {
if (drillDownDims.containsKey(dim)) {
throw new IllegalArgumentException("dimension \"" + dim + "\" already has a drill-down");
}
// TODO: we should use FilteredQuery?
// So scores of the drill-down query don't have an
// effect:
final ConstantScoreQuery drillDownQuery = new ConstantScoreQuery(subFilter);
drillDownQuery.setBoost(0.0f);
query.add(drillDownQuery, Occur.MUST);
drillDownDims.put(dim, drillDownDims.size());
}
static Filter getFilter(Query query) {
if (query instanceof ConstantScoreQuery) {
ConstantScoreQuery csq = (ConstantScoreQuery) query;
Filter filter = csq.getFilter();
if (filter != null) {
return filter;
} else {
return getFilter(csq.getQuery());
}
} else {
return null;
}
}
@Override
public DrillDownQuery clone() {
return new DrillDownQuery(config, query, drillDownDims);
}
@Override
public int hashCode() {
final int prime = 31;
int result = super.hashCode();
return prime * result + query.hashCode();
}
@Override
public boolean equals(Object obj) {
if (!(obj instanceof DrillDownQuery)) {
return false;
}
DrillDownQuery other = (DrillDownQuery) obj;
return query.equals(other.query) && super.equals(other);
}
@Override
public Query rewrite(IndexReader r) throws IOException {
if (query.clauses().size() == 0) {
return new MatchAllDocsQuery();
}
List<Filter> filters = new ArrayList<Filter>();
List<Query> queries = new ArrayList<Query>();
List<BooleanClause> clauses = query.clauses();
Query baseQuery;
int startIndex;
if (drillDownDims.size() == query.clauses().size()) {
baseQuery = new MatchAllDocsQuery();
startIndex = 0;
} else {
baseQuery = clauses.get(0).getQuery();
startIndex = 1;
}
for(int i=startIndex;i<clauses.size();i++) {
BooleanClause clause = clauses.get(i);
Query queryClause = clause.getQuery();
Filter filter = getFilter(queryClause);
if (filter != null) {
filters.add(filter);
} else {
queries.add(queryClause);
}
}
if (filters.isEmpty()) {
return query;
} else {
// Wrap all filters using FilteredQuery
// TODO: this is hackish; we need to do it because
// BooleanQuery can't be trusted to handle the
// "expensive filter" case. Really, each Filter should
// know its cost and we should take that more
// carefully into account when picking the right
// strategy/optimization:
Query wrapped;
if (queries.isEmpty()) {
wrapped = baseQuery;
} else {
// disable coord
BooleanQuery wrappedBQ = new BooleanQuery(true);
if ((baseQuery instanceof MatchAllDocsQuery) == false) {
wrappedBQ.add(baseQuery, BooleanClause.Occur.MUST);
}
for(Query q : queries) {
wrappedBQ.add(q, BooleanClause.Occur.MUST);
}
wrapped = wrappedBQ;
}
for(Filter filter : filters) {
wrapped = new FilteredQuery(wrapped, filter, FilteredQuery.QUERY_FIRST_FILTER_STRATEGY);
}
return wrapped;
}
}
@Override
public String toString(String field) {
return query.toString(field);
}
BooleanQuery getBooleanQuery() {
return query;
}
Map<String,Integer> getDims() {
return drillDownDims;
}
}