Make LibraryObject and RelativeGeometry thread-safe

CityDoctorParent/CityDoctorModel/src/main/java/de/hft/stuttgart/citydoctor2/datastructure/LibraryObject.java

@@ -9,8 +9,9 @@ import org.apache.logging.log4j.Logger;
 
 import java.io.Serial;
 import java.nio.file.Path;
-import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 
 /**
  * Reference object for handling of implicit geometries with a library object contained in an external file
@@ -24,7 +25,7 @@ public class LibraryObject extends Geometry {
     private static final long serialVersionUID = -50293435187454911L;
     private final String filepath;
     private final ParserConfiguration config;
-    private static HashMap<String, LibraryObject> libraryObjects = new HashMap<>();
+    private static Map<String, LibraryObject> libraryObjects = new ConcurrentHashMap<>();
 
     public static LibraryObject of(Path path, ParserConfiguration config) {
         if (libraryObjects.containsKey(path.toString())) {

CityDoctorParent/CityDoctorModel/src/main/java/de/hft/stuttgart/citydoctor2/datastructure/RelativeGeometry.java

@@ -5,7 +5,8 @@ import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
 import java.io.Serial;
-import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 
 /**
  * Reference object for handling of implicit geometries with a relative geometry
@@ -18,7 +19,7 @@ public class RelativeGeometry extends Geometry {
     @Serial
     private static final long serialVersionUID = -686112245455298977L;
 
-    private static HashMap<Geometry, RelativeGeometry> relativeGeometries = new HashMap<>();
+    private static Map<Geometry, RelativeGeometry> relativeGeometries = new ConcurrentHashMap<>();
 
     public static RelativeGeometry of(Geometry geom) {
         if (relativeGeometries.containsKey(geom)) {