create empty resource files for missing locales in ResourceSets

Since we know how empty resource files look, we can create them to prevent
Exceptions when loading ResourceSets with new locales.

Fixes #52

Author: Vogel612

src/main/java/de/vogel612/helper/data/ResourceFile.java

@@ -101,6 +101,7 @@ public static Stream<ResourceFile> getResourceFiles(Path folder, String name) th
     }
 
     public static Stream<ResourceFile> getResourceFiles(ResourceSet resourceSet) throws IOException {
+        resourceSet.files().filter(p -> !p.toFile().exists()).forEach(DataUtilities::createEmptyResourceFile);
         return resourceSet.files().map(ResourceFile::new);
     }
 }

src/main/java/de/vogel612/helper/data/util/DataUtilities.java

@@ -15,6 +15,69 @@
  * benefit from the abstraction
  */
 public class DataUtilities {
+
+    private static final String EMPTY_RESOURCE_FILE = "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n" +
+            "<root>\n" +
+            "  <xsd:schema id=\"root\" xmlns=\"\" xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\" xmlns:msdata=\"urn:schemas-microsoft-com:xml-msdata\">\n" +
+            "    <xsd:import namespace=\"http://www.w3.org/XML/1998/namespace\" />\n" +
+            "    <xsd:element name=\"root\" msdata:IsDataSet=\"true\">\n" +
+            "      <xsd:complexType>\n" +
+            "        <xsd:choice maxOccurs=\"unbounded\">\n" +
+            "          <xsd:element name=\"metadata\">\n" +
+            "            <xsd:complexType>\n" +
+            "              <xsd:sequence>\n" +
+            "                <xsd:element name=\"value\" type=\"xsd:string\" minOccurs=\"0\" />\n" +
+            "              </xsd:sequence>\n" +
+            "              <xsd:attribute name=\"name\" use=\"required\" type=\"xsd:string\" />\n" +
+            "              <xsd:attribute name=\"type\" type=\"xsd:string\" />\n" +
+            "              <xsd:attribute name=\"mimetype\" type=\"xsd:string\" />\n" +
+            "              <xsd:attribute ref=\"xml:space\" />\n" +
+            "            </xsd:complexType>\n" +
+            "          </xsd:element>\n" +
+            "          <xsd:element name=\"assembly\">\n" +
+            "            <xsd:complexType>\n" +
+            "              <xsd:attribute name=\"alias\" type=\"xsd:string\" />\n" +
+            "              <xsd:attribute name=\"name\" type=\"xsd:string\" />\n" +
+            "            </xsd:complexType>\n" +
+            "          </xsd:element>\n" +
+            "          <xsd:element name=\"data\">\n" +
+            "            <xsd:complexType>\n" +
+            "              <xsd:sequence>\n" +
+            "                <xsd:element name=\"value\" type=\"xsd:string\" minOccurs=\"0\" msdata:Ordinal=\"1\" />\n" +
+            "                <xsd:element name=\"comment\" type=\"xsd:string\" minOccurs=\"0\" msdata:Ordinal=\"2\" />\n" +
+            "              </xsd:sequence>\n" +
+            "              <xsd:attribute name=\"name\" type=\"xsd:string\" use=\"required\" msdata:Ordinal=\"1\" />\n" +
+            "              <xsd:attribute name=\"type\" type=\"xsd:string\" msdata:Ordinal=\"3\" />\n" +
+            "              <xsd:attribute name=\"mimetype\" type=\"xsd:string\" msdata:Ordinal=\"4\" />\n" +
+            "              <xsd:attribute ref=\"xml:space\" />\n" +
+            "            </xsd:complexType>\n" +
+            "          </xsd:element>\n" +
+            "          <xsd:element name=\"resheader\">\n" +
+            "            <xsd:complexType>\n" +
+            "              <xsd:sequence>\n" +
+            "                <xsd:element name=\"value\" type=\"xsd:string\" minOccurs=\"0\" msdata:Ordinal=\"1\" />\n" +
+            "              </xsd:sequence>\n" +
+            "              <xsd:attribute name=\"name\" type=\"xsd:string\" use=\"required\" />\n" +
+            "            </xsd:complexType>\n" +
+            "          </xsd:element>\n" +
+            "        </xsd:choice>\n" +
+            "      </xsd:complexType>\n" +
+            "    </xsd:element>\n" +
+            "  </xsd:schema>\n" +
+            "  <resheader name=\"resmimetype\">\n" +
+            "    <value>text/microsoft-resx</value>\n" +
+            "  </resheader>\n" +
+            "  <resheader name=\"version\">\n" +
+            "    <value>2.0</value>\n" +
+            "  </resheader>\n" +
+            "  <resheader name=\"reader\">\n" +
+            "    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>\n" +
+            "  </resheader>\n" +
+            "  <resheader name=\"writer\">\n" +
+            "    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>\n" +
+            "  </resheader>\n" +
+            "</data>";
+
     public static final String SINGLE_TRUTH_LOCALE = "";
 
     private static final String FILE_NAME_FORMAT = "%s%s.resx";
@@ -93,4 +156,22 @@ public static String getFileIdentifier(Path file) {
             throw new IllegalArgumentException("The resx file does not match our permissive regex");
         }
     }
+
+    /**
+     * Creates an empty resource file at the given path, assuming the file does not exist already
+     *
+     * @param path
+     *         The Path where the resource file needs to be created.
+     */
+    public static void createEmptyResourceFile(Path path) {
+        if (path.toFile().exists()) {
+            return;
+        }
+        try {
+            Files.createFile(path);
+            Files.write(path, EMPTY_RESOURCE_FILE.getBytes());
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
 }