Refactor to read/write files of graph and map data

src/main/java/GraphDataObjectReader.java

@@ -0,0 +1,32 @@
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.ObjectInputStream;
+
+public class GraphDataObjectReader {
+    private GraphWithMapData data;
+    private String filename;
+
+    public GraphDataObjectReader(String filename) throws IOException {
+        if(!filename.matches(".*\\.ser")){
+            filename = filename + ".ser";
+        }
+        this.filename = filename;
+        try(//don't need to close these because of try-with-resources
+                FileInputStream fileIn = new FileInputStream(filename);
+                ObjectInputStream in = new ObjectInputStream(fileIn))
+        {
+            data = (GraphWithMapData) in.readObject();
+        } catch (FileNotFoundException | ClassNotFoundException ex) {
+            ex.printStackTrace();
+        }
+    }
+
+    public GraphWithMapData getData() {
+        return data;
+    }
+
+    public String getFilename() {
+        return filename;
+    }
+}