if there is only a metadata file, delete it.

Author: tburch

src/main/java/com/lowtuna/jsonblob/core/BlobDataDirectoryCleaner.java

@@ -81,6 +81,14 @@ protected boolean handleDirectory(File directory, int depth, Collection<String>
       return false;
     }
 
+    if (directory.listFiles().length == 1) {
+      if (directory.listFiles()[0].getName().startsWith(FileSystemJsonBlobManager.BLOB_METADATA_FILE_NAME)) {
+        log.info("{} has only a metadata file, so it's being deleted", directory.getAbsolutePath());
+        directory.delete();
+        return false;
+      }
+    }
+
     boolean process = true;
     if (isDataDir(directory.getAbsolutePath())) {
       String[] dateParts = directory.getAbsolutePath().replace(dataDirectoryPath.toFile().getAbsolutePath(), "").split("/", 4);

src/main/java/com/lowtuna/jsonblob/core/FileSystemJsonBlobManager.java

@@ -45,6 +45,8 @@
  */
 @Slf4j
 public class FileSystemJsonBlobManager implements JsonBlobManager, Runnable, Managed {
+  public static final String BLOB_METADATA_FILE_NAME = "blobMetadata";
+
   private static final DateTimeFormatter DIRECTORY_FORMAT = DateTimeFormat.forPattern("yyyy/MM/dd");
 
   @GuardedBy("lastAccessedLock")
@@ -91,7 +93,7 @@ File getMetaDataFile(String blobId) {
   }
 
   File getMetaDataFile(File blobDirectory) {
-    return new File(blobDirectory, "blobMetadata" + ".json.gz");
+    return new File(blobDirectory, BLOB_METADATA_FILE_NAME + ".json.gz");
   }
 
   Optional<DateTime> resolveTimestamp(String blobId) {