refactor: Resolved issue #2979 Refactor Front Controller (#2986)

Co-authored-by: Mayankchoudhary294 <mayankchoudhary4302@example.com>

front-controller/src/main/java/com/iluwatar/front/controller/App.java

@@ -25,14 +25,14 @@
 package com.iluwatar.front.controller;
 
 /**
- * The Front Controller is a presentation tier pattern. Essentially it defines a controller that
+ * The Front Controller is a presentation tier pattern. Essentially, it defines a controller that
  * handles all requests for a website.
  *
  * <p>The Front Controller pattern consolidates request handling through a single handler object (
- * {@link FrontController}). This object can carry out the common the behavior such as
- * authorization, request logging and routing requests to corresponding views.
+ * {@link FrontController}). This object can carry out common behavior such as authorization,
+ * request logging and routing requests to corresponding views.
  *
- * <p>Typically the requests are mapped to command objects ({@link Command}) which then display the
+ * <p>Typically, the requests are mapped to command objects ({@link Command}) which then display the
  * correct view ({@link View}).
  *
  * <p>In this example we have implemented two views: {@link ArcherView} and {@link CatapultView}.

front-controller/src/main/java/com/iluwatar/front/controller/Dispatcher.java

@@ -0,0 +1,72 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * 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 com.iluwatar.front.controller;
+
+/**
+ * The Dispatcher class is responsible for handling the dispatching of requests to the appropriate
+ * command. It retrieves the corresponding command based on the request and invokes the command's
+ * process method to handle the business logic.
+ */
+public class Dispatcher {
+
+  /**
+   * Dispatches the request to the appropriate command.
+   *
+   * @param request the request to be handled
+   */
+  public void dispatch(String request) {
+    var command = getCommand(request);
+    command.process();
+  }
+
+  /**
+   * Retrieves the appropriate command instance for the given request.
+   *
+   * @param request the request to be handled
+   * @return the command instance corresponding to the request
+   */
+  Command getCommand(String request) {
+    var commandClass = getCommandClass(request);
+    try {
+      return (Command) commandClass.getDeclaredConstructor().newInstance();
+    } catch (Exception e) {
+      throw new ApplicationException(e);
+    }
+  }
+
+  /**
+   * Retrieves the Class object for the command corresponding to the given request.
+   *
+   * @param request the request to be handled
+   * @return the Class object of the command corresponding to the request
+   */
+  static Class<?> getCommandClass(String request) {
+    try {
+      return Class.forName("com.iluwatar.front.controller." + request + "Command");
+    } catch (ClassNotFoundException e) {
+      return UnknownCommand.class;
+    }
+  }
+}

front-controller/src/main/java/com/iluwatar/front/controller/FrontController.java

@@ -25,30 +25,19 @@
 package com.iluwatar.front.controller;
 
 /**
- * FrontController is the handler class that takes in all the requests and renders the correct
- * response.
+ * The FrontController is responsible for handling all incoming requests. It delegates
+ * the processing of requests to the Dispatcher, which then determines the appropriate
+ * command and view to render the correct response.
  */
 public class FrontController {
 
+  private final Dispatcher dispatcher;
+
+  public FrontController() {
+    this.dispatcher = new Dispatcher();
+  }
+
   public void handleRequest(String request) {
-    var command = getCommand(request);
-    command.process();
-  }
-
-  private Command getCommand(String request) {
-    var commandClass = getCommandClass(request);
-    try {
-      return (Command) commandClass.getDeclaredConstructor().newInstance();
-    } catch (Exception e) {
-      throw new ApplicationException(e);
-    }
-  }
-
-  private static Class<?> getCommandClass(String request) {
-    try {
-      return Class.forName("com.iluwatar.front.controller." + request + "Command");
-    } catch (ClassNotFoundException e) {
-      return UnknownCommand.class;
-    }
+    dispatcher.dispatch(request);
   }
 }