Feat: Add Embedded database implementation

CityDoctorParent/CityDoctorModel/src/main/java/de/hft/stuttgart/citydoctor2/database/DatabaseHandler.java

+package de.hft.stuttgart.citydoctor2.database;
+
+import de.hft.stuttgart.citydoctor2.datastructure.BoundingBox;
+import de.hft.stuttgart.citydoctor2.datastructure.CityObject;
+import de.hft.stuttgart.citydoctor2.datastructure.GmlId;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.h2gis.functions.factory.H2GISDBFactory;
+import org.h2gis.utilities.wrapper.ConnectionWrapper;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+public class DatabaseHandler {
+
+    private static final Logger logger = LogManager.getLogger(DatabaseHandler.class);
+    private static final String DB_NAME = "cd_db";
+
+
+    /**
+     * Sets up a new, empty embedded database. Will override an existing embedded database.
+     */
+    public static void setupDatabase() {
+        try {
+            H2GISDBFactory.createSpatialDataBase(DB_NAME,
+                    true, ";FILE_LOCK=SOCKET");
+            setupFeaturesTable();
+        } catch (Exception e) {
+            logger.fatal("FATAL ERROR: Creation of embedded database failed!");
+            logger.fatal(e.getMessage());
+        }
+
+
+    }
+
+    public static void setupFeaturesTable() {
+        try (Connection con = new ConnectionWrapper(H2GISDBFactory.openSpatialDataBase(DB_NAME))) {
+            try (PreparedStatement dropPs = con.prepareStatement("DROP TABLE IF EXISTS features")) {
+                dropPs.executeUpdate();
+                if (logger.isDebugEnabled()) {
+                    logger.debug("Dropped existing features table");
+                }
+            }
+            try (PreparedStatement createPs = con.prepareStatement("CREATE TABLE features (gmlid VARCHAR(255) PRIMARY KEY," +
+                    "bbox GEOMETRY, data BLOB, type VARCHAR(255) NOT NULL)")) {
+                createPs.executeUpdate();
+                if (logger.isDebugEnabled()) {
+                    logger.debug("Created features table");
+                }
+            }
+
+        } catch (SQLException e) {
+            logger.fatal("FATAL ERROR: Creation of CityDoctorModel database table failed!");
+            logger.fatal(e.getMessage());
+        }
+    }
+
+    public static void marshallCityObject(CityObject co) {
+        try (Connection con = new ConnectionWrapper(H2GISDBFactory.openSpatialDataBase(DB_NAME))) {
+            try (PreparedStatement ps = con.prepareStatement("MERGE INTO features VALUES (?, ?, ?, ?)")) {
+                ps.setString(1, co.getGmlId().toString());
+                String bbox = BoundingBox.of(co.getHighestLodGeometry().getPolygons()).toWktShadow();
+                ps.setString(2, bbox);
+                if (logger.isDebugEnabled()) {
+                    logger.debug("Attempting to serialize city object {} ", co);
+                }
+                ps.setString(4, co.getClass().getSimpleName());
+                ByteArrayOutputStream bos = new ByteArrayOutputStream();
+                try (ObjectOutputStream out = new ObjectOutputStream(bos)) {
+                    out.writeObject(co);
+                }
+                byte[] bytes = bos.toByteArray();
+                ByteArrayInputStream bis = new ByteArrayInputStream(bytes);
+                ps.setBinaryStream(3, bis, bytes.length);
+                ps.executeUpdate();
+                logger.debug("Successfully serialized CityObject to database");
+            }
+        } catch (SQLException e) {
+            logger.error("Saving of city object to embedded database failed!");
+            logger.debug(e.getMessage());
+        } catch (IOException e) {
+            logger.error("Encountered unknown writing error for embedded database!");
+            logger.debug(e.getMessage());
+        }
+    }
+
+    public static CityObject unmarshallCityObject(GmlId id) {
+        try (Connection con = new ConnectionWrapper(H2GISDBFactory.openSpatialDataBase(DB_NAME))) {
+            try (PreparedStatement ps = con.prepareStatement("SELECT * FROM features WHERE gmlid = ?")) {
+                ps.setString(1, id.toString());
+                ResultSet rs = ps.executeQuery();
+                if (rs.next()) {
+                    try (InputStream is = rs.getBinaryStream("data")) {
+                        return deserializeCityObject(new ObjectInputStream(is), rs.getString("type"));
+                    }
+                }
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            } catch (ClassNotFoundException e) {
+                throw new RuntimeException(e);
+            }
+        } catch (SQLException e) {
+            logger.error("Loading of city object from embedded database failed!");
+            logger.debug(e.getMessage());
+        }
+
+        return null;
+    }
+
+    public static List<? extends CityObject> getBufferIntersectingObjects(CityObject co, Double buffersize) {
+        ResultSet rs = null;
+        try (Connection con = new ConnectionWrapper(H2GISDBFactory.openSpatialDataBase(DB_NAME))) {
+
+        } catch (SQLException e) {
+            logger.error("Connection to database failed while trying to get buffer intersecting objects!");
+            logger.debug(e.getMessage());
+        }
+        return Collections.emptyList();
+    }
+
+    public static List<CityObject> getBBoxIntersectingObjects(CityObject co) {
+        List<CityObject> intersectingObjects = new ArrayList<>();
+
+        try (Connection con = new ConnectionWrapper(H2GISDBFactory.openSpatialDataBase(DB_NAME))) {
+            try (PreparedStatement ps = con.prepareStatement("SELECT * FROM features AS tab1" +
+                    " WHERE ST_INTERSECTS(tab1.geom, (SELECT GEOM FROM features WHERE gmlid = ?)) AND tab1.gmlid <> ?")) {
+                ps.setString(1, co.getGmlId().toString());
+                ps.setString(2, co.getGmlId().toString());
+                ResultSet rs = ps.executeQuery();
+                intersectingObjects.addAll(retrieveCityObjects(rs));
+            }
+        } catch (SQLException e) {
+            logger.error("Connection to database failed while trying to get bbox intersecting objects!");
+            logger.debug(e.getMessage());
+        }
+        return intersectingObjects;
+    }
+
+    private static List<? extends CityObject> retrieveCityObjects(ResultSet rs) throws SQLException {
+        List<CityObject> cos = new ArrayList<>();
+        while (rs.next()) {
+            try (InputStream is = rs.getBinaryStream("data")) {
+                cos.add(deserializeCityObject(new ObjectInputStream(is), rs.getString("type")));
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            } catch (ClassNotFoundException e) {
+                throw new RuntimeException(e);
+            }
+        }
+        return cos;
+    }
+
+    private static CityObject deserializeCityObject(ObjectInputStream ois, String className) throws IOException, ClassNotFoundException {
+        Class<?> type = Class.forName(className);
+        return (CityObject) type.cast(ois.readObject());
+    }
+}

CityDoctorParent/pom.xml

@@ -251,6 +251,11 @@
             <version>4.6.1</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.orbisgis</groupId>
+            <artifactId>h2gis</artifactId>
+            <version>2.2.3</version>
+        </dependency>
         <dependency>
             <groupId>org.openjfx</groupId>
             <artifactId>javafx-controls</artifactId>