/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2014, Open Source Geospatial Foundation (OSGeo)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*/
package org.geotools.data.solr;
import java.io.StringWriter;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.TimeZone;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.geotools.geometry.jts.JTS;
import org.opengis.filter.Filter;
import org.opengis.filter.expression.Add;
import org.opengis.filter.expression.Divide;
import org.opengis.filter.expression.ExpressionVisitor;
import org.opengis.filter.expression.Function;
import org.opengis.filter.expression.Literal;
import org.opengis.filter.expression.Multiply;
import org.opengis.filter.expression.NilExpression;
import org.opengis.filter.expression.PropertyName;
import org.opengis.filter.expression.Subtract;
import org.opengis.filter.temporal.After;
import org.opengis.filter.temporal.Before;
import org.opengis.filter.temporal.Begins;
import org.opengis.filter.temporal.BegunBy;
import org.opengis.filter.temporal.During;
import org.opengis.filter.temporal.EndedBy;
import org.opengis.filter.temporal.Ends;
import org.opengis.filter.temporal.TContains;
import org.opengis.temporal.Period;
import com.vividsolutions.jts.densify.Densifier;
import com.vividsolutions.jts.geom.Envelope;
import com.vividsolutions.jts.geom.Geometry;
/**
* Encodes a OGC expression into a SOLR query syntax
*
* @see {@link FilterToSolr}
*/
public class ExpressionToSolr implements ExpressionVisitor {
private static Logger LOGGER = org.geotools.util.logging.Logging.getLogger(ExpressionToSolr.class);
private static final Envelope WORLD = new Envelope(-180,180,-90,90);
private static final double SOLR_DISTANCE_TOLERANCE = 180;
/**
* Default format used to SOLR to compare date type fields, timezone will set to UTC
*/
protected SimpleDateFormat dateFormatUTC = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
/*
* Filter that contains expression to encode
*/
private Filter filter;
/*
* strategy for specific solr type
*/
private SolrSpatialStrategy spatialStrategy;
public ExpressionToSolr() {
dateFormatUTC.setTimeZone(TimeZone.getTimeZone("UTC"));
}
/**
* Construct an expression encoder with parent Filter
*/
public ExpressionToSolr(Filter filter) {
this();
this.filter = filter;
}
public void setSpatialStrategy(SolrSpatialStrategy spatialStrategy) {
this.spatialStrategy = spatialStrategy;
}
@Override
public Object visit(NilExpression expression, Object extraData) {
throw new UnsupportedOperationException("Nil expression not supported");
}
@Override
public Object visit(Add expression, Object extraData) {
throw new UnsupportedOperationException("Add expression not supported");
}
@Override
public Object visit(Divide expression, Object extraData) {
throw new UnsupportedOperationException("Divide expression not supported");
}
@Override
public Object visit(Function expression, Object extraData) {
throw new UnsupportedOperationException("Function expression not supported");
}
@Override
public Object visit(Multiply expression, Object extraData) {
throw new UnsupportedOperationException("Multiply expression not supported");
}
@Override
public Object visit(Subtract expression, Object extraData) {
throw new UnsupportedOperationException("Subtract expression not supported");
}
@Override
public Object visit(Literal expression, Object extraData) {
StringBuffer temp = new StringBuffer("");
StringWriter output = FilterToSolr.asStringWriter(extraData);
Object literal = expression.getValue();
if (literal instanceof Geometry) {
if (spatialStrategy == null) {
throw new IllegalStateException("Attempt to encode geometry literal but spatialStrategy is null");
}
Geometry geometry = (Geometry) literal;
if (!WORLD.contains(geometry.getEnvelopeInternal()) && !WORLD.equals(geometry.getEnvelopeInternal())) {
if(LOGGER.isLoggable(Level.FINE)){
LOGGER.fine("SOLR cannot deal with filters using geometries that span beyond the whole world, clip feature geometry to world");
}
geometry = geometry.intersection(JTS.toGeometry(WORLD));
}
//Splits segments exceeds the 180 degrees longitude limit to conforms to SOLR WKT manager specification
//Using JTS Densify, all segments exceeds the 180 degrees length will be densified, not only the one exceeds it in longitude!
Envelope env = geometry.getEnvelopeInternal();
if(env.getWidth() > SOLR_DISTANCE_TOLERANCE){
if(LOGGER.isLoggable(Level.FINE)){
LOGGER.fine("Split segment exceeds the 180 degree longitude limit to conform to SOLR WKT manager specification");
}
Densifier densifier = new Densifier(geometry);
densifier.setDistanceTolerance(SOLR_DISTANCE_TOLERANCE);
if(LOGGER.isLoggable(Level.FINE)){
LOGGER.fine("Original geometry: " + geometry.toText());
}
geometry = densifier.getResultGeometry();
if(LOGGER.isLoggable(Level.FINE)){
LOGGER.fine("Densified geometry: " + geometry.toText());
}
}
temp.append(spatialStrategy.encode(geometry));
} else if (literal instanceof Number) {
// don't convert to string
temp.append(literal.toString());
} else if (literal instanceof Date) {
temp.append("\"" + dateFormatUTC.format(literal) + "\"");
} else if (literal instanceof Period) {
if (filter instanceof After) {
Period period = (Period) literal;
temp.append(dateFormatUTC.format(period.getEnding().getPosition().getDate()));
}
if (filter instanceof Before || filter instanceof Begins || filter instanceof BegunBy) {
Period period = (Period) literal;
temp.append("\""
+ dateFormatUTC.format(period.getBeginning().getPosition().getDate())
+ "\"");
}
if (filter instanceof Ends || filter instanceof EndedBy) {
Period period = (Period) literal;
temp.append("\"" + dateFormatUTC.format(period.getEnding().getPosition().getDate())
+ "\"");
}
if (filter instanceof During || filter instanceof TContains) {
Period period = (Period) literal;
temp.append("\""
+ dateFormatUTC.format(period.getBeginning().getPosition().getDate())
+ "\"");
temp.append(" TO ");
temp.append("\"" + dateFormatUTC.format(period.getEnding().getPosition().getDate())
+ "\"");
}
} else {
String escaped = FilterToSolr.escapeSpecialCharacters(literal.toString());
escaped = "\"" + escaped + "\"";
temp.append(escaped);
}
output.append(temp);
return temp;
}
@Override
public Object visit(PropertyName expression, Object extraData) {
StringBuffer temp = new StringBuffer("");
StringWriter output = FilterToSolr.asStringWriter(extraData);
temp.append(expression.getPropertyName());
output.append(temp);
return temp;
}
}