Fix NFE and some other possible issues (#502)

Fixes #499

src/main/java/com/Acrobot/ChestShop/Listeners/Block/SignCreate.java

@@ -31,7 +31,7 @@ public class SignCreate implements Listener {
 
         Sign sign = (Sign) signBlock.getState();
 
-        if (ChestShopSign.isValid(sign) && !NameManager.canUseName(event.getPlayer(), OTHER_NAME_DESTROY, ChestShopSign.getOwner(sign))) {
+        if (ChestShopSign.isValid(event.getLines()) && !NameManager.canUseName(event.getPlayer(), OTHER_NAME_DESTROY, ChestShopSign.getOwner(event.getLines()))) {
             event.setCancelled(true);
             sign.update();
             return;

src/main/java/com/Acrobot/ChestShop/Listeners/Modules/PriceRestrictionModule.java

@@ -114,7 +114,7 @@ public class PriceRestrictionModule implements Listener {
         String itemType = material.getType().toString().toLowerCase(Locale.ROOT);
         int amount;
         try {
-            amount = ChestShopSign.getQuantity(event.getSign());
+            amount = ChestShopSign.getQuantity(event.getSignLines());
         } catch (IllegalArgumentException e) {
             return;
         }

src/main/java/com/Acrobot/ChestShop/Listeners/Modules/StockCounterModule.java

@@ -36,7 +36,7 @@ public class StockCounterModule implements Listener {
     public static void onPreShopCreation(PreShopCreationEvent event) {
         int quantity;
         try {
-            quantity = ChestShopSign.getQuantity(event.getSign());
+            quantity = ChestShopSign.getQuantity(event.getSignLines());
         } catch (IllegalArgumentException invalidQuantity) {
             return;
         }

src/main/java/com/Acrobot/ChestShop/Listeners/PostShopCreation/ShopCreationLogger.java

@@ -21,8 +21,8 @@ public class ShopCreationLogger implements Listener {
             String shopOwner = ChestShopSign.getOwner(event.getSignLines());
             String typeOfShop = ChestShopSign.isAdminShop(shopOwner) ? "an Admin Shop" : "a shop" + (event.createdByOwner() ? "" : " for " + event.getOwnerAccount().getName());
 
-            String item = ChestShopSign.getQuantity(event.getSign()) + ' ' + ChestShopSign.getItem(event.getSign());
-            String prices = ChestShopSign.getPrice(event.getSign());
+            String item = ChestShopSign.getQuantity(event.getSignLines()) + ' ' + ChestShopSign.getItem(event.getSignLines());
+            String prices = ChestShopSign.getPrice(event.getSignLines());
             String location = LocationUtil.locationToString(event.getSign().getLocation());
 
             String message = String.format(CREATION_MESSAGE,

src/main/java/com/Acrobot/ChestShop/Listeners/PostShopCreation/SignSticker.java

@@ -24,7 +24,7 @@ public class SignSticker implements Listener {
             return;
         }
 
-        if (ChestShopSign.isAdminShop(event.getSign())) {
+        if (ChestShopSign.isAdminShop(event.getSignLines())) {
             return;
         }
 

src/main/java/com/Acrobot/ChestShop/Listeners/PreShopCreation/CreationFeeGetter.java

@@ -32,7 +32,7 @@ public class CreationFeeGetter implements Listener {
             return;
         }
 
-        if (ChestShopSign.isAdminShop(event.getSign())) {
+        if (ChestShopSign.isAdminShop(event.getSignLines())) {
             return;
         }
 

src/main/java/com/Acrobot/ChestShop/Listeners/PreShopCreation/MoneyChecker.java

@@ -28,7 +28,7 @@ public class MoneyChecker implements Listener {
             return;
         }
 
-        if (ChestShopSign.isAdminShop(event.getSign())) {
+        if (ChestShopSign.isAdminShop(event.getSignLines())) {
             return;
         }
 

src/main/java/com/Acrobot/ChestShop/Listeners/PreShopCreation/PermissionChecker.java

@@ -35,8 +35,8 @@ public class PermissionChecker implements Listener {
             return;
         }
 
-        String priceLine = ChestShopSign.getPrice(event.getSign());
-        String itemLine = ChestShopSign.getItem(event.getSign());
+        String priceLine = ChestShopSign.getPrice(event.getSignLines());
+        String itemLine = ChestShopSign.getItem(event.getSignLines());
 
         ItemParseEvent parseEvent = new ItemParseEvent(itemLine);
         Bukkit.getPluginManager().callEvent(parseEvent);