Add the setting changes encoding for CSV file to the preference dialog

(cherry picked from commit 11210b6d8b4584621ef02e7356854ffa9f7f2647)

src/main/java/ninja/javafx/smartcsv/preferences/EncodingFileWriter.java

@@ -0,0 +1,59 @@
+/*
+   The MIT License (MIT)
+   -----------------------------------------------------------------------------
+
+   Copyright (c) 2015-2016 javafx.ninja <info@javafx.ninja>
+
+   Permission is hereby granted, free of charge, to any person obtaining a copy
+   of this software and associated documentation files (the "Software"), to deal
+   in the Software without restriction, including without limitation the rights
+   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+   copies of the Software, and to permit persons to whom the Software is
+   furnished to do so, subject to the following conditions:
+
+   The above copyright notice and this permission notice shall be included in
+   all copies or substantial portions of the Software.
+
+   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+   THE SOFTWARE.
+
+*/
+
+package ninja.javafx.smartcsv.preferences;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import ninja.javafx.smartcsv.FileWriter;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Save the file encoding to configuration file
+ */
+public class EncodingFileWriter implements FileWriter<String> {
+
+    private String fileEncoding;
+
+    @Override
+    public void setContent(String fileEncoding) {
+        this.fileEncoding = fileEncoding;
+    }
+
+    @Override
+    public void write(File filename) throws IOException {
+        Map<String, String> encodings = new HashMap<>();
+        encodings.put("fileEncoding", CharsetHelper.getCharsetName(fileEncoding));
+        Gson gson = new GsonBuilder().setPrettyPrinting().create();
+        Files.write(filename.toPath(), gson.toJson(encodings).getBytes());
+    }
+
+}