/*
* 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.geopoint.document;
import java.util.Objects;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
import org.apache.lucene.analysis.tokenattributes.PositionIncrementAttribute;
import org.apache.lucene.analysis.tokenattributes.TermToBytesRefAttribute;
import org.apache.lucene.util.Attribute;
import org.apache.lucene.util.AttributeFactory;
import org.apache.lucene.util.AttributeImpl;
import org.apache.lucene.util.AttributeReflector;
import org.apache.lucene.util.BytesRef;
import org.apache.lucene.util.BytesRefBuilder;
import static org.apache.lucene.spatial.geopoint.document.GeoPointField.geoCodedToPrefixCoded;
import static org.apache.lucene.spatial.geopoint.document.GeoPointField.PRECISION_STEP;
/**
* <b>Expert:</b> This class provides a {@link TokenStream} used by {@link GeoPointField}
* for encoding GeoPoint terms.
*
* This class encodes terms up to a maximum of {@link #MAX_SHIFT} using a fixed precision step defined by
* {@link GeoPointField#PRECISION_STEP}. This yields a total of 4 terms per GeoPoint
* each consisting of 5 bytes (4 prefix bytes + 1 precision byte).
*
* Here's an example usage:
*
* <pre class="prettyprint">
* // using prefix terms
* GeoPointField geoPointField = new GeoPointField(fieldName1, lat, lon, GeoPointField.TYPE_NOT_STORED);
* document.add(geoPointField);
*
* // query by bounding box
* Query q = new GeoPointInBBoxQuery(fieldName1, minLat, maxLat, minLon, maxLon);
*
* // query by distance
* q = new GeoPointDistanceQuery(fieldName2, centerLat, centerLon, radiusMeters);
* </pre>
*
* @lucene.experimental
*/
final class GeoPointTokenStream extends TokenStream {
private static final int MAX_SHIFT = PRECISION_STEP * 4;
private final GeoPointTermAttribute geoPointTermAtt = addAttribute(GeoPointTermAttribute.class);
private final PositionIncrementAttribute posIncrAtt = addAttribute(PositionIncrementAttribute.class);
private boolean isInit = false;
/**
* Expert: Creates a token stream for geo point fields with the specified
* <code>precisionStep</code> using the given
* {@link org.apache.lucene.util.AttributeFactory}.
* The stream is not yet initialized,
* before using set a value using the various setGeoCode method.
*/
public GeoPointTokenStream() {
super(new GeoPointAttributeFactory(AttributeFactory.DEFAULT_ATTRIBUTE_FACTORY));
assert PRECISION_STEP > 0;
}
public GeoPointTokenStream setGeoCode(final long geoCode) {
geoPointTermAtt.init(geoCode, MAX_SHIFT-PRECISION_STEP);
isInit = true;
return this;
}
@Override
public void reset() {
if (isInit == false) {
throw new IllegalStateException("call setGeoCode() before usage");
}
}
@Override
public boolean incrementToken() {
if (isInit == false) {
throw new IllegalStateException("call setGeoCode() before usage");
}
// this will only clear all other attributes in this TokenStream
clearAttributes();
final int shift = geoPointTermAtt.incShift();
posIncrAtt.setPositionIncrement((shift == MAX_SHIFT) ? 1 : 0);
return (shift < 63);
}
/**
* Tracks shift values during encoding
*/
public interface GeoPointTermAttribute extends Attribute {
/** Returns current shift value, undefined before first token */
int getShift();
/** <em>Don't call this method!</em>
* @lucene.internal */
void init(long value, int shift);
/** <em>Don't call this method!</em>
* @lucene.internal */
int incShift();
}
// just a wrapper to prevent adding CTA
private static final class GeoPointAttributeFactory extends AttributeFactory {
private final AttributeFactory delegate;
GeoPointAttributeFactory(AttributeFactory delegate) {
this.delegate = delegate;
}
@Override
public AttributeImpl createAttributeInstance(Class<? extends Attribute> attClass) {
if (CharTermAttribute.class.isAssignableFrom(attClass)) {
throw new IllegalArgumentException("GeoPointTokenStream does not support CharTermAttribute.");
}
return delegate.createAttributeInstance(attClass);
}
}
public static final class GeoPointTermAttributeImpl extends AttributeImpl implements GeoPointTermAttribute,TermToBytesRefAttribute {
private long value = 0L;
private int shift = 0;
private BytesRefBuilder bytes = new BytesRefBuilder();
public GeoPointTermAttributeImpl() {
this.shift = MAX_SHIFT-PRECISION_STEP;
}
@Override
public BytesRef getBytesRef() {
geoCodedToPrefixCoded(value, shift, bytes);
return bytes.get();
}
@Override
public void init(long value, int shift) {
this.value = value;
this.shift = shift;
}
@Override
public int getShift() { return shift; }
@Override
public int incShift() {
return (shift += PRECISION_STEP);
}
@Override
public void clear() {
// this attribute has no contents to clear!
// we keep it untouched as it's fully controlled by outer class.
}
@Override
public void reflectWith(AttributeReflector reflector) {
reflector.reflect(TermToBytesRefAttribute.class, "bytes", getBytesRef());
reflector.reflect(GeoPointTermAttribute.class, "shift", shift);
}
@Override
public void copyTo(AttributeImpl target) {
final GeoPointTermAttribute a = (GeoPointTermAttribute) target;
a.init(value, shift);
}
@Override
public GeoPointTermAttributeImpl clone() {
GeoPointTermAttributeImpl t = (GeoPointTermAttributeImpl)super.clone();
// Do a deep clone
t.bytes = new BytesRefBuilder();
t.bytes.copyBytes(getBytesRef());
return t;
}
@Override
public int hashCode() {
return Objects.hash(shift, value);
}
@Override
public boolean equals(Object obj) {
if (this == obj) return true;
if (obj == null) return false;
if (getClass() != obj.getClass()) return false;
GeoPointTermAttributeImpl other = (GeoPointTermAttributeImpl) obj;
if (shift != other.shift) return false;
if (value != other.value) return false;
return true;
}
}
/** override toString because it can throw cryptic "illegal shift value": */
@Override
public String toString() {
return getClass().getSimpleName() + "(precisionStep=" + PRECISION_STEP + " shift=" + geoPointTermAtt.getShift() + ")";
}
}