add some necessary guards for mission package

risk-server/src/main/java/org/nominoe/datatypes/mission/ConcreteMissionFactory.java

@@ -18,6 +18,10 @@ public class ConcreteMissionFactory implements MissionFactory {
      */
     @Override
     public Mission createMissionCaptureContinents(Continent continent1, Continent continent2) {
+
+        if (continent1 == null || continent2 == null) {
+            throw new IllegalArgumentException("Continents cannot be null");
+        }
         return new MissionCaptureContinents(continent1, continent2);
     }
 
@@ -28,6 +32,10 @@ public class ConcreteMissionFactory implements MissionFactory {
      */
     @Override
     public Mission createMissionCaptureTerritories(int nbTerritoires) {
+
+        if (nbTerritoires <= 0) {
+            throw new IllegalArgumentException("Number of territories must be positive");
+        }
         return new MissionCaptureTerritories(nbTerritoires);
     }
 
@@ -38,6 +46,10 @@ public class ConcreteMissionFactory implements MissionFactory {
      */
     @Override
     public Mission createMissionDestroyOpponent(Color target) {
+
+        if (target == null) {
+            throw new IllegalArgumentException("Target color cannot be null");
+        }
         return new MissionDestroyOpponent(target);
     }
 }

risk-server/src/main/java/org/nominoe/datatypes/mission/MissionCaptureContinents.java

@@ -26,6 +26,10 @@ public class MissionCaptureContinents extends Mission {
      */
     protected MissionCaptureContinents(Continent continent1, Continent continent2) {
         super("Vous devez conquerir les continents suivants : " + continent1.getName() + " et " + continent2.getName() + ".");
+
+        if (continent1 == null || continent2 == null) {
+            throw new IllegalArgumentException("Continent parameters cannot be null");
+        }
         this.continent1 = continent1;
         this.continent2 = continent2;
     }
@@ -38,13 +42,12 @@ public class MissionCaptureContinents extends Mission {
      */
     @Override
     public boolean isSuccessful(Player playerDontOnCheckVictory, Set<Player> players) {
-        if (playerDontOnCheckVictory != null) {
-            if (players != null) {
-                if (players.size() > 0) {
-                    return (playerDontOnCheckVictory.getContinentsControls().contains(continent1)
-                            && playerDontOnCheckVictory.getContinentsControls().contains(continent2));
-                }
-            }
+        if (playerDontOnCheckVictory == null) {
+            throw new IllegalArgumentException("Player parameter cannot be null");
+        }
+        if (players != null && players.size() > 0) {
+            return (playerDontOnCheckVictory.getContinentsControls().contains(continent1)
+                    && playerDontOnCheckVictory.getContinentsControls().contains(continent2));
         }
         return false;
 

risk-server/src/main/java/org/nominoe/datatypes/mission/MissionCaptureTerritories.java

@@ -24,6 +24,10 @@ public class MissionCaptureTerritories extends Mission {
      */
     protected MissionCaptureTerritories(int nbTerritories) {
         super("Vous devez conquerir " + nbTerritories + " territoires.");
+
+        if (nbTerritories <= 0) {
+            throw new IllegalArgumentException("The number of territories to capture must be positive.");
+        }
         this.nbTerritories = nbTerritories;
     }
 
@@ -32,14 +36,13 @@ public class MissionCaptureTerritories extends Mission {
      */
     @Override
     public boolean isSuccessful(Player playerDontOnCheckVictory, Set<Player> players) {
-        if (Objects.nonNull(playerDontOnCheckVictory)) {
-            if (Objects.nonNull(players)) {
-                if (players.size() > 0) {
-                    return playerDontOnCheckVictory.nbOwnedTerritories() >= nbTerritories;
-                }
-            }
+        if (playerDontOnCheckVictory == null) {
+            throw new IllegalArgumentException("The player to check for victory cannot be null.");
+        }
+        if (players == null || players.isEmpty()) {
+            throw new IllegalArgumentException("The set of players cannot be null or empty.");
         }
 
-        return false;
+        return playerDontOnCheckVictory.nbOwnedTerritories() >= nbTerritories;
     }
 }

risk-server/src/main/java/org/nominoe/datatypes/mission/MissionDestroyOpponent.java

@@ -45,23 +45,18 @@ public class MissionDestroyOpponent extends Mission {
      */
     @Override
     public boolean isSuccessful(Player playerDontOnCheckVictory, Set<Player> players) {
-        if (playerDontOnCheckVictory != null) {
-            if (players != null) {
-                if (!players.isEmpty()) {
-                    // Check if the target player is eliminated
-                    for (Player j : players) {
-                        if (target.equals(j.getColor())) {
-                            return (j.nbOwnedTerritories() == 0);
-                        }
-                    }
-                    // Check if the player conquers 25 territories
-                    return playerDontOnCheckVictory.getPossessedTerritories().size() >= CONQUERING_TERRITORIES;
-                } else {
-                    return false;
+        if (playerDontOnCheckVictory == null || players == null || players.isEmpty()) {
+            return false;
+        }
+        // Check if the target player is eliminated
+        if (target != null) {
+            for (Player j : players) {
+                if (target.equals(j.getColor())) {
+                    return (j.nbOwnedTerritories() == 0);
                 }
-            } else {
-                return false;
             }
-        } else return false;
+        }
+        // Check if the player conquers 25 territories
+        return playerDontOnCheckVictory.getPossessedTerritories().size() >= CONQUERING_TERRITORIES;
     }
 }