Add NFC and NFD file name normalization for uploading files

This is needed in case the path encoding on the filesystem differs from the path encoding in the meta data.

src/main/java/org/purl/sword/server/fedora/fedoraObjects/LocalDatastream.java

@@ -56,6 +56,7 @@
 import java.io.IOException;
 import java.net.URI;
 import java.net.URISyntaxException;
+import java.text.Normalizer;
 
 /**
  * This encapsulates datastreams which are on the local file system
@@ -195,7 +196,11 @@ private File getFileInstance() throws IOException {
         File file;
         if (_path.startsWith("file:")) {
             try {
-                file = new File(new URI(_path));
+                file = tryNormalizedFilename(_path, Normalizer.Form.NFC);
+                if (!file.exists()) {
+                    LOG.warn("Could'nt find file by NFC normalized file name. Fallback to NFD normalization...");
+                    file = tryNormalizedFilename(_path, Normalizer.Form.NFD);
+                }
             } catch (URISyntaxException e) {
                 throw new IOException("File URI is not valid: " + _path);
             }
@@ -204,4 +209,8 @@ private File getFileInstance() throws IOException {
         }
         return file;
     }
+
+    private File tryNormalizedFilename(String path, Normalizer.Form form) throws URISyntaxException {
+        return new File(new URI(Normalizer.normalize(path, form)));
+    }
 }