package org.apache.lucene.spatial.serialized;
/*
* 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 com.spatial4j.core.context.SpatialContext;
import com.spatial4j.core.io.BinaryCodec;
import com.spatial4j.core.shape.Point;
import com.spatial4j.core.shape.Shape;
import org.apache.lucene.document.BinaryDocValuesField;
import org.apache.lucene.document.Field;
import org.apache.lucene.index.AtomicReaderContext;
import org.apache.lucene.index.BinaryDocValues;
import org.apache.lucene.queries.function.FunctionValues;
import org.apache.lucene.queries.function.ValueSource;
import org.apache.lucene.search.DocIdSet;
import org.apache.lucene.search.DocIdSetIterator;
import org.apache.lucene.search.Explanation;
import org.apache.lucene.search.Filter;
import org.apache.lucene.search.Query;
import org.apache.lucene.spatial.SpatialStrategy;
import org.apache.lucene.spatial.query.SpatialArgs;
import org.apache.lucene.spatial.util.DistanceToShapeValueSource;
import org.apache.lucene.spatial.util.ShapePredicateValueSource;
import org.apache.lucene.util.Bits;
import org.apache.lucene.util.BytesRef;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.FilterOutputStream;
import java.io.IOException;
import java.util.Map;
/**
* A SpatialStrategy based on serializing a Shape stored into BinaryDocValues.
* This is not at all fast; it's designed to be used in conjuction with another index based
* SpatialStrategy that is approximated (like {@link org.apache.lucene.spatial.prefix.RecursivePrefixTreeStrategy})
* to add precision or eventually make more specific / advanced calculations on the per-document
* geometry.
* The serialization uses Spatial4j's {@link com.spatial4j.core.io.BinaryCodec}.
*
* @lucene.experimental
*/
public class SerializedDVStrategy extends SpatialStrategy {
/**
* A cache heuristic for the buf size based on the last shape size.
*/
//TODO do we make this non-volatile since it's merely a heuristic?
private volatile int indexLastBufSize = 8 * 1024;//8KB default on first run
/**
* Constructs the spatial strategy with its mandatory arguments.
*/
public SerializedDVStrategy(SpatialContext ctx, String fieldName) {
super(ctx, fieldName);
}
@Override
public Field[] createIndexableFields(Shape shape) {
int bufSize = Math.max(128, (int) (this.indexLastBufSize * 1.5));//50% headroom over last
ByteArrayOutputStream byteStream = new ByteArrayOutputStream(bufSize);
final BytesRef bytesRef = new BytesRef();//receiver of byteStream's bytes
try {
ctx.getBinaryCodec().writeShape(new DataOutputStream(byteStream), shape);
//this is a hack to avoid redundant byte array copying by byteStream.toByteArray()
byteStream.writeTo(new FilterOutputStream(null/*not used*/) {
@Override
public void write(byte[] b, int off, int len) throws IOException {
bytesRef.bytes = b;
bytesRef.offset = off;
bytesRef.length = len;
}
});
} catch (IOException e) {
throw new RuntimeException(e);
}
this.indexLastBufSize = bytesRef.length;//cache heuristic
return new Field[]{new BinaryDocValuesField(getFieldName(), bytesRef)};
}
@Override
public ValueSource makeDistanceValueSource(Point queryPoint, double multiplier) {
//TODO if makeShapeValueSource gets lifted to the top; this could become a generic impl.
return new DistanceToShapeValueSource(makeShapeValueSource(), queryPoint, multiplier, ctx);
}
@Override
public Query makeQuery(SpatialArgs args) {
throw new UnsupportedOperationException("This strategy can't return a query that operates" +
" efficiently. Instead try a Filter or ValueSource.");
}
/**
* Returns a Filter that should be used with {@link org.apache.lucene.search.FilteredQuery#QUERY_FIRST_FILTER_STRATEGY}.
* Use in another manner is likely to result in an {@link java.lang.UnsupportedOperationException}
* to prevent misuse because the filter can't efficiently work via iteration.
*/
@Override
public Filter makeFilter(final SpatialArgs args) {
ValueSource shapeValueSource = makeShapeValueSource();
ShapePredicateValueSource predicateValueSource = new ShapePredicateValueSource(
shapeValueSource, args.getOperation(), args.getShape());
return new PredicateValueSourceFilter(predicateValueSource);
}
/**
* Provides access to each shape per document as a ValueSource in which
* {@link org.apache.lucene.queries.function.FunctionValues#objectVal(int)} returns a {@link
* Shape}.
*/ //TODO raise to SpatialStrategy
public ValueSource makeShapeValueSource() {
return new ShapeDocValueSource(getFieldName(), ctx.getBinaryCodec());
}
/** This filter only supports returning a DocSet with a bits(). If you try to grab the
* iterator then you'll get an UnsupportedOperationException.
*/
static class PredicateValueSourceFilter extends Filter {
private final ValueSource predicateValueSource;//we call boolVal(doc)
public PredicateValueSourceFilter(ValueSource predicateValueSource) {
this.predicateValueSource = predicateValueSource;
}
@Override
public DocIdSet getDocIdSet(final AtomicReaderContext context, final Bits acceptDocs) throws IOException {
return new DocIdSet() {
@Override
public DocIdSetIterator iterator() throws IOException {
throw new UnsupportedOperationException(
"Iteration is too slow; instead try FilteredQuery.QUERY_FIRST_FILTER_STRATEGY");
//Note that if you're truly bent on doing this, then see FunctionValues.getRangeScorer
}
@Override
public Bits bits() throws IOException {
//null Map context -- we simply don't have one. That's ok.
final FunctionValues predFuncValues = predicateValueSource.getValues(null, context);
return new Bits() {
@Override
public boolean get(int index) {
if (acceptDocs != null && !acceptDocs.get(index))
return false;
return predFuncValues.boolVal(index);
}
@Override
public int length() {
return context.reader().maxDoc();
}
};
}
};
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
PredicateValueSourceFilter that = (PredicateValueSourceFilter) o;
if (!predicateValueSource.equals(that.predicateValueSource)) return false;
return true;
}
@Override
public int hashCode() {
return predicateValueSource.hashCode();
}
}//PredicateValueSourceFilter
/**
* Implements a ValueSource by deserializing a Shape in from BinaryDocValues using BinaryCodec.
* @see #makeShapeValueSource()
*/
static class ShapeDocValueSource extends ValueSource {
private final String fieldName;
private final BinaryCodec binaryCodec;//spatial4j
private ShapeDocValueSource(String fieldName, BinaryCodec binaryCodec) {
this.fieldName = fieldName;
this.binaryCodec = binaryCodec;
}
@Override
public FunctionValues getValues(Map context, AtomicReaderContext readerContext) throws IOException {
final BinaryDocValues docValues = readerContext.reader().getBinaryDocValues(fieldName);
return new FunctionValues() {
int bytesRefDoc = -1;
BytesRef bytesRef = new BytesRef();//scratch
boolean fillBytes(int doc) {
if (bytesRefDoc != doc) {
docValues.get(doc, bytesRef);
bytesRefDoc = doc;
}
return bytesRef.length != 0;
}
@Override
public boolean exists(int doc) {
return fillBytes(doc);
}
@Override
public boolean bytesVal(int doc, BytesRef target) {
if (fillBytes(doc)) {
target.bytes = bytesRef.bytes;
target.offset = bytesRef.offset;
target.length = bytesRef.length;
return true;
} else {
target.length = 0;
return false;
}
}
@Override
public Object objectVal(int docId) {
if (!fillBytes(docId))
return null;
DataInputStream dataInput = new DataInputStream(
new ByteArrayInputStream(bytesRef.bytes, bytesRef.offset, bytesRef.length));
try {
return binaryCodec.readShape(dataInput);
} catch (IOException e) {
throw new RuntimeException(e);
}
}
@Override
public Explanation explain(int doc) {
return new Explanation(Float.NaN, toString(doc));
}
@Override
public String toString(int doc) {
return description() + "=" + objectVal(doc);//TODO truncate?
}
};
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
ShapeDocValueSource that = (ShapeDocValueSource) o;
if (!fieldName.equals(that.fieldName)) return false;
return true;
}
@Override
public int hashCode() {
int result = fieldName.hashCode();
return result;
}
@Override
public String description() {
return "shapeDocVal(" + fieldName + ")";
}
}//ShapeDocValueSource
}