feat: terrain is now selectable

What are the key features of this change

Added a button to change the terrain. Lists the enums from Terrain. Also set a standard font size to minimum 20px. Buttons are set to 20pt = 26px. Made buttons for resetting and running the battle disabled if both armies are not imported. Updated som javadoc for battle

closes: #19 (closed)

Size of change: medium

Checklist

• Javadoc is added to methods and classes
• Tests are added to feature
• Build tool test passed

This image shows the disabled buttons.

src/main/java/edu/ntnu/idatt2001/carljgu/battle/Battle.java

@@ -11,7 +11,7 @@ import java.util.Random;
  * Class Battle that simulates a battle between two armies.
  *
  * @author Carl Gützkow
- * @version 1.2 13.02.2022
+ * @version 1.3 30.04.2022
  */
 public class Battle {
 
@@ -34,13 +34,16 @@ public class Battle {
      *
      * @param armyOne Army - the first army
      * @param armyTwo Army - the second army
-     * @throws IllegalArgumentException thrown if one of the armies are empty.
+     * @param terrain Terrain - on what terrain the battle is fought on.
+     * @throws IllegalArgumentException thrown if one of the armies are empty,
+     * if armies are equal or if terrain is not defined
      * @throws NullPointerException thrown if one of the armies are null object
      */
     public Battle(Army armyOne, Army armyTwo, Terrain terrain) throws IllegalArgumentException {
         if (armyOne == null || armyTwo == null) throw new NullPointerException("Army is not defined");
         if (!armyOne.hasUnits() || !armyTwo.hasUnits()) throw new IllegalArgumentException("Army can not be empty");
         if (Objects.equals(armyOne, armyTwo)) throw new IllegalArgumentException("Armies can not be the same");
+        if (terrain == null) throw new IllegalArgumentException("Terrain is not defined");
         this.armyOne = armyOne;
         this.armyTwo = armyTwo;
         this.terrain = terrain;
@@ -70,9 +73,9 @@ public class Battle {
 
     /**
      * Gets the terrain where
-     * the attack occurs.
+     * the battle occurs.
      *
-     * @return terrain - Terrain - the specified terrain.
+     * @return terrain - Terrain - on what terrain the battle is fought on.
      */
     public Terrain getTerrain() {
         return terrain;