package org.apache.lucene.spatial;
/*
* 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 org.apache.lucene.index.AtomicReaderContext;
import org.apache.lucene.queries.ChainedFilter;
import org.apache.lucene.search.BitsFilteredDocIdSet;
import org.apache.lucene.search.DocIdSet;
import org.apache.lucene.search.FieldCache;
import org.apache.lucene.search.Filter;
import org.apache.lucene.spatial.query.SpatialArgs;
import org.apache.lucene.spatial.query.SpatialOperation;
import org.apache.lucene.util.Bits;
import java.io.IOException;
/**
* A Spatial Filter implementing {@link SpatialOperation#IsDisjointTo} in terms
* of a {@link SpatialStrategy}'s support for {@link SpatialOperation#Intersects}.
* A document is considered disjoint if it has spatial data that does not
* intersect with the query shape. Another way of looking at this is that it's
* a way to invert a query shape.
*
* @lucene.experimental
*/
public class DisjointSpatialFilter extends Filter {
private final String field;//maybe null
private final Filter intersectsFilter;
/**
*
* @param strategy Needed to compute intersects
* @param args Used in spatial intersection
* @param field This field is used to determine which docs have spatial data via
* {@link org.apache.lucene.search.FieldCache#getDocsWithField(org.apache.lucene.index.AtomicReader, String)}.
* Passing null will assume all docs have spatial data.
*/
public DisjointSpatialFilter(SpatialStrategy strategy, SpatialArgs args, String field) {
this.field = field;
// TODO consider making SpatialArgs cloneable
SpatialOperation origOp = args.getOperation();//copy so we can restore
args.setOperation(SpatialOperation.Intersects);//temporarily set to intersects
intersectsFilter = strategy.makeFilter(args);
args.setOperation(origOp);//restore so it looks like it was
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
DisjointSpatialFilter that = (DisjointSpatialFilter) o;
if (field != null ? !field.equals(that.field) : that.field != null)
return false;
if (!intersectsFilter.equals(that.intersectsFilter)) return false;
return true;
}
@Override
public int hashCode() {
int result = field != null ? field.hashCode() : 0;
result = 31 * result + intersectsFilter.hashCode();
return result;
}
@Override
public DocIdSet getDocIdSet(AtomicReaderContext context, final Bits acceptDocs) throws IOException {
Bits docsWithField;
if (field == null) {
docsWithField = null;//all docs
} else {
//NOTE By using the FieldCache we re-use a cache
// which is nice but loading it in this way might be slower than say using an
// intersects filter against the world bounds. So do we add a method to the
// strategy, perhaps? But the strategy can't cache it.
docsWithField = FieldCache.DEFAULT.getDocsWithField(context.reader(), field);
final int maxDoc = context.reader().maxDoc();
if (docsWithField.length() != maxDoc )
throw new IllegalStateException("Bits length should be maxDoc ("+maxDoc+") but wasn't: "+docsWithField);
if (docsWithField instanceof Bits.MatchNoBits) {
return null;//match nothing
} else if (docsWithField instanceof Bits.MatchAllBits) {
docsWithField = null;//all docs
}
}
//not so much a chain but a way to conveniently invert the Filter
DocIdSet docIdSet = new ChainedFilter(new Filter[]{intersectsFilter}, ChainedFilter.ANDNOT).getDocIdSet(context, acceptDocs);
return BitsFilteredDocIdSet.wrap(docIdSet, docsWithField);
}
}