Refactored addRing method. Ref #69

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

@@ -30,6 +30,7 @@ import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.concurrent.atomic.AtomicInteger;
 import java.util.stream.Stream;
 
 import org.citygml4j.core.model.CityGMLVersion;
@@ -173,9 +174,9 @@ public class CityDoctorModel {
 				return;
 			}
 			Map<Vertex, Integer> idMap = new LinkedHashMap<>();
-			int counter = 0;
+			AtomicInteger counter = new AtomicInteger(0);
 			for (Polygon poly : highestLod) {
-				counter = addRing(poly.getExteriorRing(), idMap, counter);
+				addRing(poly.getExteriorRing(), idMap, counter);
 			}
 			
 			try (BufferedWriter writer = Files.newBufferedWriter(folder.toPath().resolve(co.getGmlId() + ".off"))) {
@@ -209,14 +210,10 @@ public class CityDoctorModel {
 		});
 	}
 
-	private int addRing(LinearRing ring, Map<Vertex, Integer> idMap, int counter) {
+	private void addRing(LinearRing ring, Map<Vertex, Integer> idMap, AtomicInteger counter) {
 		for (Vertex v : ring.getVertices()) {
-			if (!idMap.containsKey(v)) {
-				idMap.put(v, counter);
-				counter++;
-			}
+			idMap.computeIfAbsent(v, k -> counter.getAndIncrement());
 		}
-		return counter;
 	}
 
 	public Set<CheckError> collectErrors() {