Refactor

src/main/java/eu/simstadt/regionchooser/RegionChooserBrowser.java

 package eu.simstadt.regionchooser;
 
-import java.io.BufferedWriter;
 import java.io.File;
 import java.io.IOException;
-import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.logging.Logger;
@@ -32,7 +30,6 @@ public class RegionChooserBrowser extends Region
 {
 	private static final Logger LOGGER = Logger.getLogger(RegionChooserBrowser.class.getName());
 	private static final String PREF_RECENT_REPOSITORY = "RECENT_REPOSITORY";
-	private static final int BUFFER = 1024;
 
 	/**
 	 * JavaFX Backend for RegionChooser. Inside simstadt_openlayers.js frontend, this class is available as `fxapp`.
@@ -88,21 +85,9 @@ public void downloadRegionFromCityGMLs(String wktPolygon, String project, String
 
 			File buildingIdsFile = selectSaveFileWithDialog(project,
 					csvCitygmls.replace(";", "_").replace(".gml", ""), "selected_region");
-			writeStringBuilderToFile(sb, buildingIdsFile.toPath());
+			RegionChooserUtils.writeStringBuilderToFile(sb, buildingIdsFile.toPath());
 		}
 
-		private void writeStringBuilderToFile(StringBuilder sb, Path outputFile) throws IOException {
-			if (outputFile != null) {
-				try (BufferedWriter writer = Files.newBufferedWriter(outputFile)) {
-					char[] chars = new char[BUFFER];
-					for (int aPosStart = 0; aPosStart < sb.length(); aPosStart += BUFFER) {
-						int chunk = Math.min(BUFFER, sb.length() - aPosStart);
-						sb.getChars(aPosStart, aPosStart + chunk, chars, 0);
-						writer.write(chars, 0, chunk);
-					}
-				}
-			}
-		}
 
 		public void selectRepository() {
 			Preferences userPrefs = Preferences.userRoot().node("/eu/simstadt/desktop");

src/main/java/eu/simstadt/regionchooser/RegionChooserUtils.java

 package eu.simstadt.regionchooser;
 
+import java.io.BufferedWriter;
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
@@ -23,6 +24,7 @@
 	private static final Pattern srsNamePattern = Pattern.compile("(?i)(?<=srsName=[\"'])[^\"']+(?=[\"'])");
 	private static final int CITYGML_HEADER_LENGTH = 50;
 	private static final String EPSG = "EPSG:";
+	private static final int BUFFER = 1024;
 
 	private RegionChooserUtils() {
 		// only static use
@@ -32,14 +34,14 @@ private RegionChooserUtils() {
 	 * The srsName (The name by which this reference system is identified) inside the CityGML file can have multiple
 	 * formats. This method tries to parse the string and detect the corresponding reference system. If it is found, it
 	 * returns a proj4j.CoordinateReferenceSystem. It throws an IllegalArgumentException otherwise.
-	 * 
+	 *
 	 * This method should be able to parse any EPSG id : e.g. "EPSG:1234". German Citygmls might also have "DE_DHDN_3GK3"
 	 * or "ETRS89_UTM32" as srsName, so those are also included. It isn't guaranteed that those formats are correctly
 	 * parsed, though.
-	 * 
+	 *
 	 * The EPSG ids and parameters are defined in resources ('nad/epsg') inside proj4j-0.1.0.jar. Some EPSG ids are
 	 * missing though, e.g. 7415
-	 * 
+	 *
 	 * @param srsName
 	 * @return CoordinateReferenceSystem
 	 */
@@ -85,9 +87,9 @@ private static CoordinateReferenceSystem crsFromSrsName(String srsName) {
 
 	/**
 	 * Converts a jts.geom.Polygon from one CoordinateReferenceSystem to another.
-	 * 
+	 *
 	 * NOTE: It would be easier with org.geotools.referencing.CRS instead of Proj4J
-	 * 
+	 *
 	 * @param polygonInOriginalCRS
 	 * @param originalCRS
 	 * @param newCRS
@@ -108,11 +110,11 @@ public static Polygon changePolygonCRS(Polygon polygonInOriginalCRS, CoordinateR
 	}
 
 	/**
-	 * 
+	 *
 	 * Fast scan of the 50 first lines of a Citygml file to look for srsName. It might not be as reliable as parsing the
 	 * whole CityGML, but it should be much faster and use much less memory. For a more reliable solution, use
 	 * GeoCoordinatesAccessor. This solution can be convenient for Web services, RegionChooser or HullExtractor.
-	 * 
+	 *
 	 * @param citygmlPath
 	 * @return
 	 * @throws IOException
@@ -132,7 +134,7 @@ public static CoordinateReferenceSystem crsFromCityGMLHeader(Path citygmlPath) t
 
 	/**
 	 * Finds every CityGML in every .proj folder in a repository.
-	 * 
+	 *
 	 * @param repository
 	 * @return a stream of CityGML Paths
 	 * @throws IOException
@@ -146,4 +148,17 @@ public static Stream<Path> everyCityGML(Path repository) throws IOException {
 								p.toString().toLowerCase().endsWith(".gml"));
 	}
 
+
+	public static void writeStringBuilderToFile(StringBuilder sb, Path outputFile) throws IOException {
+		if (outputFile != null) {
+			try (BufferedWriter writer = Files.newBufferedWriter(outputFile)) {
+				char[] chars = new char[BUFFER];
+				for (int aPosStart = 0; aPosStart < sb.length(); aPosStart += BUFFER) {
+					int chunk = Math.min(BUFFER, sb.length() - aPosStart);
+					sb.getChars(aPosStart, aPosStart + chunk, chars, 0);
+					writer.write(chars, 0, chunk);
+				}
+			}
+		}
+	}
 }