Fix: Fix batch-unmarshalling

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

+package de.hft.stuttgart.citydoctor2.database;
+
+import com.github.benmanes.caffeine.cache.CacheLoader;
+import de.hft.stuttgart.citydoctor2.exceptions.EmbeddedDatabaseHandlerException;
+import org.jspecify.annotations.NonNull;
+
+import java.util.Map;
+import java.util.Set;
+
+public class DatabaseCacheLoader<K, V> implements CacheLoader<K, V> {
+
+    private final Unmarshaller<K, V> unmarshaller;
+    private final BatchUnmarshaller<K, V> batchUnmarshaller;
+
+    public DatabaseCacheLoader(Unmarshaller<K,V> unmarshaller, BatchUnmarshaller<K, V> batchUnmarshaller){
+        this.unmarshaller = unmarshaller;
+        this.batchUnmarshaller = batchUnmarshaller;
+    }
+
+    @Override
+    public @NonNull V load(@NonNull K key) throws EmbeddedDatabaseHandlerException {
+        return unmarshaller.unmarshall(key);
+    }
+
+    @Override
+    @NonNull
+    public Map<K, V> loadAll(@NonNull Set<? extends K> keys) throws EmbeddedDatabaseHandlerException {
+        return batchUnmarshaller.unmarshall(keys);
+    }
+
+    public interface Unmarshaller<K, V> {
+        V unmarshall(K key) throws EmbeddedDatabaseHandlerException;
+    }
+
+    public interface BatchUnmarshaller<K, V> {
+        Map<K, V> unmarshall(Set<? extends K> keys) throws EmbeddedDatabaseHandlerException;
+    }
+
+}

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

@@ -24,6 +24,7 @@ import java.io.InputStream;
 import java.io.InvalidClassException;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.sql.Array;
 import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.PreparedStatement;
@@ -33,6 +34,7 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Set;
 
 /**
@@ -259,7 +261,9 @@ public class EmbeddedDatabaseHandler {
         try (Connection con = dataSource.getConnection()) {
             try (PreparedStatement ps = con.prepareStatement(
                     "SELECT data FROM features WHERE ARRAY_CONTAINS(? ,gmlid)")) {
-                ps.setObject(1, ids);
+                String[] idStrings = ids.stream().map(Objects::toString).toArray(String[]::new);
+                Array array = con.createArrayOf("VARCHAR(255)", idStrings);
+                ps.setArray(1, array);
                 ResultSet rs = ps.executeQuery();
                 Map<GmlId, CityObject> objects= new HashMap<>();
                 while (rs.next()) {

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

@@ -8,9 +8,9 @@ import de.hft.stuttgart.citydoctor2.datastructure.GmlId;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
-import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
@@ -49,11 +49,13 @@ public class FeatureCache implements CityObjectCache{
 
     public FeatureCache(EmbeddedDatabaseConfiguration dbConfig){
         handler = new EmbeddedDatabaseHandler(dbConfig);
+        DatabaseCacheLoader.Unmarshaller<GmlId, CityObject> single = handler::unmarshallCityObject;
+        DatabaseCacheLoader.BatchUnmarshaller<GmlId, CityObject> batch = handler::unmarshallAllIds;
         cache = Caffeine.newBuilder().maximumSize(3000).removalListener((GmlId key, CityObject value, RemovalCause cause) -> {
             if (value != null && cause.wasEvicted() && isFeatureMarshallable(value)){
                 handler.marshallCityObject(value);
             }
-        }).build(handler::unmarshallCityObject);
+        }).build(new DatabaseCacheLoader<>(single, batch));
     }
 
     /**
@@ -119,7 +121,7 @@ public class FeatureCache implements CityObjectCache{
 
     @Override
     public Collection<CityObject> getAll(List<GmlId> ids){
-        Map<GmlId, CityObject> map = cache.getAll(ids, handler::unmarshallAllIds);
+        Map<GmlId, CityObject> map = cache.getAll(new HashSet<>(ids));
         return map.values();
     }
 

CityDoctorParent/CityDoctorValidation/src/main/java/de/hft/stuttgart/citydoctor2/checks/util/CollectionUtils.java

@@ -20,7 +20,9 @@ package de.hft.stuttgart.citydoctor2.checks.util;
 
 import java.util.Arrays;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Set;
+import java.util.stream.IntStream;
 
 public class CollectionUtils {
 	
@@ -40,4 +42,11 @@ public class CollectionUtils {
 		return set;
 	}
 
+	public static <T> List<List<T>> partition(List<T> list, int chunkSize){
+		return IntStream.iterate(0, i-> i < list.size(), i-> i+ chunkSize)
+				.mapToObj(i -> list.subList(i, Math.min(i+chunkSize, list.size())))
+				.toList();
+
+	}
+
 }