Fixes #36

src/main/java/net/knarcraft/minigames/arena/dropper/DropperArena.java

@@ -263,7 +263,7 @@ public class DropperArena implements Arena {
      * @param newLocation <p>The new spawn location</p>
      * @return <p>True if successfully updated</p>
      */
-    public boolean setSpawnLocation(@NotNull Location newLocation) {
+    public boolean setSpawnLocation(@Nullable Location newLocation) {
         if (isInvalid(newLocation)) {
             return false;
         } else {
@@ -279,7 +279,7 @@ public class DropperArena implements Arena {
      * @param newLocation <p>The new exit location</p>
      * @return <p>True if successfully updated</p>
      */
-    public boolean setExitLocation(@NotNull Location newLocation) {
+    public boolean setExitLocation(@Nullable Location newLocation) {
         if (isInvalid(newLocation)) {
             return false;
         } else {

src/main/java/net/knarcraft/minigames/arena/parkour/ParkourArena.java

@@ -356,7 +356,7 @@ public class ParkourArena implements Arena {
      * @param newLocation <p>The new spawn location</p>
      * @return <p>True if successfully updated</p>
      */
-    public boolean setSpawnLocation(@NotNull Location newLocation) {
+    public boolean setSpawnLocation(@Nullable Location newLocation) {
         if (isInvalid(newLocation)) {
             return false;
         } else {
@@ -372,7 +372,7 @@ public class ParkourArena implements Arena {
      * @param newLocation <p>The new exit location</p>
      * @return <p>True if successfully updated</p>
      */
-    public boolean setExitLocation(@NotNull Location newLocation) {
+    public boolean setExitLocation(@Nullable Location newLocation) {
         if (isInvalid(newLocation)) {
             return false;
         } else {
@@ -425,13 +425,18 @@ public class ParkourArena implements Arena {
      * @param newLocation <p>The location players have to reach</p>
      * @return <p>True if successfully changed</p>
      */
-    public boolean setWinLocation(@NotNull Location newLocation) {
-        if (isInvalid(newLocation)) {
-            return false;
-        } else {
+    public boolean setWinLocation(@Nullable Location newLocation) {
+        if (newLocation == null) {
+            // Un-set the win location, and fall back to the win block type
+            this.winLocation = null;
+            this.saveArena();
+            return true;
+        } else if (!isInvalid(newLocation)) {
             this.winLocation = newLocation.clone();
             this.saveArena();
             return true;
+        } else {
+            return false;
         }
     }
 
@@ -485,7 +490,7 @@ public class ParkourArena implements Arena {
      * @param checkpoint <p>The checkpoint to add</p>
      * @return <p>True if successfully added</p>
      */
-    public boolean addCheckpoint(@NotNull Location checkpoint) {
+    public boolean addCheckpoint(@Nullable Location checkpoint) {
         if (isInvalid(checkpoint)) {
             return false;
         }

src/main/java/net/knarcraft/minigames/command/parkour/EditParkourArenaCommand.java

@@ -5,6 +5,7 @@ import net.knarcraft.minigames.MiniGames;
 import net.knarcraft.minigames.arena.parkour.ParkourArena;
 import net.knarcraft.minigames.arena.parkour.ParkourArenaEditableProperty;
 import net.knarcraft.minigames.config.MiniGameMessage;
+import net.knarcraft.minigames.util.InputValidationHelper;
 import org.bukkit.Location;
 import org.bukkit.Material;
 import org.bukkit.command.Command;
@@ -12,6 +13,7 @@ import org.bukkit.command.CommandExecutor;
 import org.bukkit.command.CommandSender;
 import org.bukkit.entity.Player;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.HashSet;
 import java.util.List;
@@ -109,7 +111,7 @@ public class EditParkourArenaCommand implements CommandExecutor {
      * @param locationString <p>The location string to parse</p>
      * @return <p>The parsed location, or the player's location if not parse-able</p>
      */
-    private @NotNull Location parseLocation(Player player, String locationString) {
+    private @Nullable Location parseLocation(Player player, String locationString) {
         if ((locationString.trim() + ",").matches("([0-9]+.?[0-9]*,){3}")) {
             String[] parts = locationString.split(",");
             Location newLocation = player.getLocation().clone();
@@ -117,6 +119,8 @@ public class EditParkourArenaCommand implements CommandExecutor {
             newLocation.setY(Double.parseDouble(parts[1].trim()));
             newLocation.setZ(Double.parseDouble(parts[2].trim()));
             return newLocation;
+        } else if (InputValidationHelper.isEmptyValue(locationString)) {
+            return null;
         } else {
             return player.getLocation().clone();
         }

src/main/java/net/knarcraft/minigames/util/InputValidationHelper.java

@@ -2,6 +2,8 @@ package net.knarcraft.minigames.util;
 
 import org.bukkit.Location;
 import org.bukkit.World;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 /**
  * A helper class for validating whether given input is valid
@@ -18,9 +20,23 @@ public final class InputValidationHelper {
      * @param location <p>The location to validate</p>
      * @return <p>False if the location is valid</p>
      */
-    public static boolean isInvalid(Location location) {
+    public static boolean isInvalid(@Nullable Location location) {
+        if (location == null) {
+            return true;
+        }
         World world = location.getWorld();
         return world == null || !world.getWorldBorder().isInside(location);
     }
 
+    /**
+     * Checks whether the given value can be considered "empty"
+     *
+     * @param value <p>The value to check</p>
+     * @return <p>True if the value can be considered as empty</p>
+     */
+    public static boolean isEmptyValue(@NotNull String value) {
+        return value.equalsIgnoreCase("null") || value.equalsIgnoreCase("0") ||
+                value.equalsIgnoreCase("clear") || value.equalsIgnoreCase("none");
+    }
+
 }

src/main/java/net/knarcraft/minigames/util/TabCompleteHelper.java

@@ -36,7 +36,8 @@ public final class TabCompleteHelper {
      *
      * @return <p>All arena names</p>
      */
-    public static @NotNull List<String> getDropperArenas() {
+    @NotNull
+    public static List<String> getDropperArenas() {
         return getArenas(MiniGames.getInstance().getDropperArenaHandler());
     }
 
@@ -45,7 +46,8 @@ public final class TabCompleteHelper {
      *
      * @return <p>All arena names</p>
      */
-    public static @NotNull List<String> getParkourArenas() {
+    @NotNull
+    public static List<String> getParkourArenas() {
         return getArenas(MiniGames.getInstance().getParkourArenaHandler());
     }
 
@@ -54,7 +56,8 @@ public final class TabCompleteHelper {
      *
      * @return <p>All arena names</p>
      */
-    private static @NotNull List<String> getArenas(ArenaHandler<?, ?> arenaHandler) {
+    @NotNull
+    private static List<String> getArenas(@NotNull ArenaHandler<?, ?> arenaHandler) {
         List<String> arenaNames = new ArrayList<>();
         for (Arena arena : arenaHandler.getArenas().values()) {
             arenaNames.add(arena.getArenaName());
@@ -67,7 +70,8 @@ public final class TabCompleteHelper {
      *
      * @return <p>All arena properties</p>
      */
-    public static @NotNull List<String> getDropperArenaProperties() {
+    @NotNull
+    public static List<String> getDropperArenaProperties() {
         List<String> arenaProperties = new ArrayList<>();
         for (DropperArenaEditableProperty property : DropperArenaEditableProperty.values()) {
             arenaProperties.add(property.getArgumentString());
@@ -80,7 +84,8 @@ public final class TabCompleteHelper {
      *
      * @return <p>All arena properties</p>
      */
-    public static @NotNull List<String> getParkourArenaProperties() {
+    @NotNull
+    public static List<String> getParkourArenaProperties() {
         List<String> arenaProperties = new ArrayList<>();
         for (ParkourArenaEditableProperty property : ParkourArenaEditableProperty.values()) {
             arenaProperties.add(property.getArgumentString());
@@ -94,7 +99,8 @@ public final class TabCompleteHelper {
      * @param propertyType <p>The property type to get suggestions for</p>
      * @return <p>The suggestions produced</p>
      */
-    public static List<String> getTabCompleteSuggestions(EditablePropertyType propertyType) {
+    @NotNull
+    public static List<String> getTabCompleteSuggestions(@NotNull EditablePropertyType propertyType) {
         if (tabCompleteSuggestions == null) {
             tabCompleteSuggestions = new HashMap<>();
             tabCompleteSuggestions.put(EditablePropertyType.LOCATION, getLocationSuggestions());
@@ -115,6 +121,7 @@ public final class TabCompleteHelper {
      *
      * @return <p>A list of suggestions</p>
      */
+    @NotNull
     private static List<String> getDoubleSuggestions() {
         List<String> suggestions = new ArrayList<>();
         suggestions.add("0");
@@ -133,6 +140,7 @@ public final class TabCompleteHelper {
      *
      * @return <p>A list of suggestions</p>
      */
+    @NotNull
     private static List<String> getMaterialListSuggestions() {
         List<String> suggestions = new ArrayList<>();
         suggestions.add("LAVA,MAGMA_BLOCK");
@@ -146,6 +154,7 @@ public final class TabCompleteHelper {
      *
      * @return <p>A list of suggestions</p>
      */
+    @NotNull
     private static List<String> getCheckpointClearSuggestions() {
         List<String> suggestions = new ArrayList<>();
         suggestions.add("true");
@@ -157,6 +166,7 @@ public final class TabCompleteHelper {
      *
      * @return <p>A list of suggestions</p>
      */
+    @NotNull
     private static List<String> getBlockTypeSuggestions() {
         List<String> materials = new ArrayList<>();
         for (Material material : Material.values()) {
@@ -172,6 +182,7 @@ public final class TabCompleteHelper {
      *
      * @return <p>A list of suggestions</p>
      */
+    @NotNull
     private static List<String> getVerticalVelocitySuggestions() {
         List<String> velocities = new ArrayList<>();
         velocities.add("0.01");
@@ -189,6 +200,7 @@ public final class TabCompleteHelper {
      *
      * @return <p>A list of suggestions</p>
      */
+    @NotNull
     private static List<String> getHorizontalVelocitySuggestions() {
         List<String> velocities = new ArrayList<>();
         velocities.add("0.01");
@@ -203,6 +215,7 @@ public final class TabCompleteHelper {
      *
      * @return <p>A list of suggestions</p>
      */
+    @NotNull
     private static List<String> getNameSuggestions() {
         List<String> locations = new ArrayList<>();
         locations.add("DropperArena1");
@@ -217,10 +230,12 @@ public final class TabCompleteHelper {
      *
      * @return <p>A list of suggestions</p>
      */
+    @NotNull
     private static List<String> getLocationSuggestions() {
         List<String> locations = new ArrayList<>();
         locations.add("here");
         locations.add("x,y,z");
+        locations.add("null");
         return locations;
     }
 
@@ -230,7 +245,8 @@ public final class TabCompleteHelper {
      * @param typedNode <p>The full permission node typed by the player</p>
      * @return <p>All known valid auto-complete options</p>
      */
-    public static List<String> tabCompletePermission(String typedNode) {
+    @NotNull
+    public static List<String> tabCompletePermission(@NotNull String typedNode) {
         if (plugins == null) {
             loadAvailablePermissions();
         }
@@ -268,7 +284,7 @@ public final class TabCompleteHelper {
      *
      * @param permissionName <p>The permission to load</p>
      */
-    private static void loadPermission(String permissionName) {
+    private static void loadPermission(@NotNull String permissionName) {
         String[] permissionParts = permissionName.split("\\.");
         if (permissionParts.length == 1 && !plugins.contains(permissionParts[0])) {
             plugins.add(permissionParts[0]);