Merge pull request #3 from Haris-Irfan/branch-A-CodeQuality

Improve code quality

Include the exception thrown in the default case of the switch statement
in the parse method. Ensures that by default any invalid inputs will
display an "Invalid input" in the chatbot.

Include missing Java Documentation for some methods

src/main/java/kietwoforone/gui/DialogBox.java

@@ -50,12 +50,26 @@ private void flip() {
         setAlignment(Pos.TOP_LEFT);
     }
 
+    /**
+     * Returns a DialogBox instance when for the user's inputs.
+     *
+     * @param text
+     * @param img
+     * @return
+     */
     public static DialogBox getUserDialog(String text, Image img) {
         assert text != null: "Text cannot be null.";
         assert img != null: "Image cannot be null.";
         return new DialogBox(text, img);
     }
 
+    /**
+     * Returns a DialogBox instance when the chatbot responds to the user's input.
+     *
+     * @param text
+     * @param img
+     * @return
+     */
     public static DialogBox getKieDialog(String text, Image img) {
         assert text != null: "Text cannot be null.";
         assert img != null: "Image cannot be null.";

src/main/java/kietwoforone/gui/Main.java

@@ -16,6 +16,14 @@ public class Main extends Application {
 
     private KieTwoForOne kie = new KieTwoForOne();
 
+    /**
+     * Sets up the primary stage and initializes the user interface when the application is launched.
+     *
+     * @param stage the primary stage for this application, onto which
+     * the application scene can be set.
+     * Applications may create other stages, if needed, but they will not be
+     * primary stages.
+     */
     @Override
     public void start(Stage stage) {
         assert stage != null: "Stage cannot be null";

src/main/java/kietwoforone/parser/Parser.java

@@ -141,10 +141,8 @@ public static Command parse(String command) throws KieTwoForOneException {
         case FIND:
             return new FindWordCommand(instruction[1]);
         default:
-            break;
+            throw new KieTwoForOneException("Invalid input!");
         }
-
-        return new ByeCommand();
     }
 
 }

src/main/java/kietwoforone/ui/UI.java

@@ -182,6 +182,11 @@ public void showBye() {
         System.out.println(response);
     }
 
+    /**
+     * Returns the chatbot response to the user's input.
+     *
+     * @return
+     */
     public String getResponse() {
         return response;
     }