create new transform operation RemoveStopsOutsidePolygone: remove sto…

…ps outside polygone/multiPolygone

onebusaway-gtfs-transformer/pom.xml

@@ -77,6 +77,11 @@
       <groupId>com.sun.xml.bind</groupId>
       <artifactId>jaxb-impl</artifactId>
     </dependency>
+    <dependency>
+      <groupId>org.locationtech.jts</groupId>
+      <artifactId>jts-core</artifactId>
+      <version>1.19.0</version>
+    </dependency>
   </dependencies>
 
   <build>

onebusaway-gtfs-transformer/src/main/java/org/onebusaway/gtfs_transformer/impl/RemoveStopsOutsidePolygone.java

@@ -0,0 +1,99 @@
+package org.onebusaway.gtfs_transformer.impl;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import java.io.Serializable;
+
+import org.locationtech.jts.io.ParseException;
+import org.locationtech.jts.io.WKTReader;
+import org.locationtech.jts.geom.*;
+
+import org.onebusaway.csv_entities.schema.annotations.CsvField;
+import org.onebusaway.gtfs.model.IdentityBean;
+import org.onebusaway.gtfs.model.Stop;
+import org.onebusaway.gtfs.serialization.GtfsEntitySchemaFactory;
+import org.onebusaway.gtfs.services.GtfsMutableRelationalDao;
+import org.onebusaway.gtfs_transformer.factory.EntityRetentionGraph;
+import org.onebusaway.gtfs_transformer.services.GtfsTransformStrategy;
+import org.onebusaway.gtfs_transformer.services.TransformContext;
+import org.slf4j.Logger;
+
+import org.slf4j.LoggerFactory;
+
+public class RemoveStopsOutsidePolygone implements GtfsTransformStrategy {
+    private final Logger log = LoggerFactory.getLogger(RemoveStopsOutsidePolygone.class);
+
+    @CsvField(optional = true)
+    private String polygone;
+
+    public void setPolygone(String polygone) {
+        this.polygone = polygone;
+    }
+
+    @Override
+    public String getName() {
+        return this.getClass().getSimpleName();
+    }
+
+    /*
+     * example:
+     *  {"op":"transform","class":"org.onebusaway.gtfs_transformer.impl.RemoveStopsOutsidePolygone","polygone":wkt_polygone ..."}
+     */
+
+     @Override
+    public void run(TransformContext transformContext, GtfsMutableRelationalDao gtfsMutableRelationalDao) {
+        Geometry geometry = buildPolygone(polygone);
+        EntityRetentionGraph graph = new EntityRetentionGraph(gtfsMutableRelationalDao);
+        graph.setRetainBlocks(false);
+        // browse all stops and retain only those inside polygone/multiPolygone
+        if (geometry.isValid() && !geometry.isEmpty()){
+            for (Stop stop : gtfsMutableRelationalDao.getAllStops()) {
+                if (insidePolygon(geometry,stop.getLon(),stop.getLat())){
+                    graph.retain(stop, true);
+                }
+            }
+        }
+
+        // remove non retained objects
+        for (Class<?> entityClass : GtfsEntitySchemaFactory.getEntityClasses()) {
+            List<Object> objectsToRemove = new ArrayList<Object>();
+            for (Object entity : gtfsMutableRelationalDao.getAllEntitiesForType(entityClass)) {
+                if (!graph.isRetained(entity)){
+                    objectsToRemove.add(entity);
+                    }
+                }
+            for (Object toRemove : objectsToRemove){
+                gtfsMutableRelationalDao.removeEntity((IdentityBean<Serializable>) toRemove);
+                }
+            }
+        }   
+
+    /*
+     * create polygone/multiPolygone from 'polygone' variable in json file
+        * return Geometry variable
+        * return null if an exception is encountered when parsing the wkt string
+     */
+    private Geometry buildPolygone(String wktPolygone) {
+        WKTReader reader = new WKTReader();
+        try{
+            return  reader.read(wktPolygone);
+        } catch (ParseException e){
+            String message = String.format("Error parsing WKT string : %s", e.getMessage());
+            log.error(message);
+            return null;
+        }
+
+    }
+    /*
+     * insidePolygone returns boolean variable
+        * true: if polygone contains point
+        * false if point is outside polygone
+     */
+    private boolean insidePolygon(Geometry geometry, double lon, double lat) {
+        GeometryFactory geometryFactory = new GeometryFactory();
+        Point point = geometryFactory.createPoint(new Coordinate(lon, lat));
+        return geometry.contains(point);
+    }
+
+}