Resolve "Improve code quality in MainPageView"

Closes #34 (closed)

src/main/java/edu/ntnu/idatt2003/view/components/ComboBoxFactory.java

 package edu.ntnu.idatt2003.view.components;
 
 import java.util.List;
+import java.util.function.BiConsumer;
+import javafx.event.ActionEvent;
 import javafx.scene.control.ComboBox;
 
 /**
@@ -8,7 +10,14 @@ import javafx.scene.control.ComboBox;
  * The combo box has a style class "combo-box" and the values are set to the specified values.
  * Goal: Create a styled combo box with a specified prompt text, width, height and values.
  */
-public class StyledComboBox<T> extends ComboBox<T> {
+public class ComboBoxFactory {
+
+  /**
+   * Private constructor to prevent instantiation.
+   */
+  private ComboBoxFactory() {
+  }
+
   /**
    * Creates a styled combo box with a specified prompt text, width, height and values.
    * The combo box has a style class "combo-box" and the values are set to the specified values.
@@ -18,13 +27,40 @@ public class StyledComboBox<T> extends ComboBox<T> {
    * @param height     The preferred height of the combo box.
    * @param values     The values to set in the combo box.
    */
-  public StyledComboBox(String promptText, int width, int height, List<T> values) {
-    super();
-    this.setPromptText(promptText);
-    this.setPrefSize(width, height);
-    this.getStyleClass().add("combo-box");
+  public static <T> ComboBox<T> createComboBox(String promptText, int width, int height, List<T> values,
+                                               BiConsumer<ComboBox<T>, ActionEvent> eventHandler) {
+    return createComboBoxWithStyle(promptText, width, height, values, eventHandler);
+  }
+
+  public static <T> ComboBox<T> createComboBox(String promptText, int width, int height, List<T> values,
+                                               BiConsumer<ComboBox<T>, ActionEvent> eventHandler, T defaultValue) {
+    ComboBox<T> comboBox = createComboBoxWithStyle(promptText, width, height, values, eventHandler);
+    comboBox.setValue(defaultValue);
+    return comboBox;
+  }
+
+  /**
+   * Creates a styled combo box with a specified prompt text, width, height, values and events
+   * to be used in other methods in class.
+   *
+   * @param promptText   The text to display in the combo box when it is empty.
+   * @param width        The preferred width of the combo box.
+   * @param height       The preferred height of the combo box.
+   * @param values       The values to set in the combo box.
+   * @param eventHandler The event handler to set on the combo box.
+   * @return The styled combo box.
+   */
+  private static <T> ComboBox<T> createComboBoxWithStyle(String promptText, int width, int height, List<T> values,
+                                                         BiConsumer<ComboBox<T>, ActionEvent> eventHandler) {
+    ComboBox<T> comboBox = new ComboBox<>();
+    comboBox.setPromptText(promptText);
+    comboBox.setPromptText(promptText);
+    comboBox.setPrefSize(width, height);
+    comboBox.getStyleClass().add("combo-box");
+    comboBox.setOnAction(e -> eventHandler.accept(comboBox, e));
     if (values != null) {
-      this.getItems().addAll(values);
+      comboBox.getItems().addAll(values);
     }
+    return comboBox;
   }
 }