Refactor: Make Schematron run in background thread

CityDoctorParent/CityDoctorValidation/src/main/java/de/hft/stuttgart/citydoctor2/check/Checker.java

@@ -191,13 +191,26 @@ public class Checker {
         if (config == null) {
             config = ValidationConfiguration.loadStandardValidationConfig();
         }
+        Thread schematronThread = new Thread(() -> {
+            SvrlContentHandler handler = executeSchematronValidationIfAvailable(config, model.getFile());
+            if (handler != null) {
+                handleSchematronResults(handler);
+            }
+        });
+        schematronThread.start();
         checkCityModel(model, l);
         if (logger.isInfoEnabled()) {
             logger.info(Localization.getText("Checker.checksFinished"));
         }
-        SvrlContentHandler handler = executeSchematronValidationIfAvailable(config, model.getFile());
-        if (handler != null) {
-            handleSchematronResults(handler);
+        if (schematronThread.isAlive()) {
+            //TODO: Localize String
+            logger.info("Schematron thread still running, waiting for completion. This may take some time");
+            try{
+                schematronThread.join();
+            } catch (InterruptedException e) {
+                logger.error("Main Thread was interrupted while waiting for Schematron", e);
+                schematronThread.interrupt();
+            }
         }
         model.setValidated(createValidationPlan());
     }
@@ -443,6 +456,7 @@ public class Checker {
                 logger.info(Localization.getText("Checker.schematronValidation"));
             }
             if (!Files.exists(Path.of(config.getSchematronFilePath()))) {
+                //TODO: Localize String
                 logger.warn("Schematron file {} could not be found", config.getSchematronFilePath());
                 return null;
             }
@@ -563,6 +577,7 @@ public class Checker {
         for (Entry<String, RequirementConfiguration> e : config.getRequirements().entrySet()) {
             de.hft.stuttgart.citydoctor2.check.Requirement req = Checks.getAvailableRequirements().get(e.getKey());
             if (req == null) {
+                //TODO: Localize String
                 logger.warn("Could not find any check that satisfies requirement {}, it will not be checked",
                         e.getKey());
             } else {
@@ -638,7 +653,6 @@ public class Checker {
         AtomicInteger missingCount = new AtomicInteger(0);
         // clear global errors
         model.getGlobalErrors().clear();
-        CheckerThreadsSynchronizer sync = new CheckerThreadsSynchronizer(model, l);
 
         int threadCount = Runtime.getRuntime().availableProcessors() * 5;
         ExecutorService exec =  new ThreadPoolExecutor
@@ -669,9 +683,13 @@ public class Checker {
         try {
             exec.awaitTermination(30, TimeUnit.DAYS);
             long endTime = System.nanoTime();
-            logger.info("Checks finished in " + (endTime -startTime) / 1_000_000 + " ms");
+            if (logger.isDebugEnabled()){
+                logger.debug("Checks finished in {} ms", (endTime - startTime) / 1_000_000);
+            }
+
             if (missingCount.get() > 0) {
                 int missing = missingCount.get();
+                //TODO: Localize String
                 String msg = String.format("Checker could not load %d/%.0f features (%.2f%%)", missing, featureSum, (missing/featureSum) * 100);
                 logger.warn(msg);
             }