use guava's cache as implementation for the HotEntryCache

My own implementation was faster, but was not able to
implement a size limitation.

data-store/src/main/java/org/lucares/pdb/datastore/internal/DataStore.java

@@ -12,6 +12,7 @@ import java.util.Optional;
 import java.util.Set;
 import java.util.SortedSet;
 import java.util.TreeSet;
+import java.util.concurrent.ExecutionException;
 import java.util.concurrent.atomic.AtomicLong;
 
 import org.lucares.collections.LongList;
@@ -71,8 +72,7 @@ public class DataStore implements AutoCloseable {
 
 	// A Doc will never be changed once it is created. Therefore we can cache them
 	// easily.
-	private final HotEntryCache<Long, Doc> docIdToDocCache = new HotEntryCache<>(Duration.ofSeconds(5),
-			"docIdToDocCache");
+	private final HotEntryCache<Long, Doc> docIdToDocCache = new HotEntryCache<>(Duration.ofMillis(30), 100_000);
 
 	private final DiskStorage diskStorage;
 	private final Path diskStorageFilePath;
@@ -262,13 +262,17 @@ public class DataStore implements AutoCloseable {
 	}
 
 	private Doc getDocByDocId(final Long docId) {
-		return docIdToDocCache.putIfAbsent(docId, k -> {
-			try {
-				return docIdToDoc.getValue(k);
-			} catch (final IOException e) {
-				throw new RuntimeIOException(e);
-			}
-		});
+		try {
+			return docIdToDocCache.putIfAbsent(docId, () -> {
+				try {
+					return docIdToDoc.getValue(docId);
+				} catch (final IOException e) {
+					throw new RuntimeIOException(e);
+				}
+			});
+		} catch (final ExecutionException e) {
+			throw new RuntimeException(e);
+		}
 	}
 
 	@Override