Use PaperLib and make command task return completable futures

Bukkit/build.gradle

@@ -2,9 +2,11 @@ repositories {
     maven { url "https://hub.spigotmc.org/nexus/content/repositories/snapshots/" }
     maven { url "https://oss.sonatype.org/content/repositories/snapshots/" }
     maven { url "http://nexus.hc.to/content/repositories/pub_releases" }
-    maven { url "https://repo.codemc.org/repository/maven-public" }
+    maven { url = "https://repo.codemc.org/repository/maven-public" }
-    //maven { url 'http://repo.onarandombox.com/content/groups/public'}
+    maven {
-    maven { url 'https://papermc.io/repo/repository/maven-public/' }
+        name 'papermc'
+        url 'https://papermc.io/repo/repository/maven-public/'
+    }
     mavenLocal()
 }
 
@@ -15,6 +17,7 @@ dependencies {
     //implementation 'com.onarandombox.multiversecore:Multiverse-Core:3.0.0-SNAPSHOT'
     implementation 'org.spigotmc:spigot-api:1.14.3-R0.1-SNAPSHOT'
     compile(group: 'com.sk89q.worldedit', name: 'worldedit-bukkit', version: '7.0.0')
+    compile "io.papermc:paperlib:1.0.1"
     compile("net.milkbowl.vault:VaultAPI:1.7") {
         exclude module: 'bukkit'
     }
@@ -44,7 +47,10 @@ shadowJar {
         include(dependency('com.squareup.okhttp3:okhttp:3.14.0'))
         include(dependency('com.squareup.okio:okio:2.2.2'))
         include(dependency('org.jetbrains.kotlin:kotlin-stdlib:1.3.30'))
+        include(dependency("io.papermc:paperlib:1.0.1"))
     }
+    relocate 'io.papermc.lib', 'com.github.intellectualsites.plotsquared.bukkit.paperlib'
+    // relocate('org.mcstats', 'com.plotsquared.stats')
     archiveName = "${parent.name}-${project.name}-${parent.version}.jar"
     destinationDir = file '../target'
 }

Bukkit/src/main/java/com/github/intellectualsites/plotsquared/bukkit/BukkitMain.java

@@ -39,6 +39,7 @@ import com.github.intellectualsites.plotsquared.plot.util.*;
 import com.github.intellectualsites.plotsquared.plot.util.block.QueueProvider;
 import com.github.intellectualsites.plotsquared.plot.uuid.UUIDWrapper;
 import com.sk89q.worldedit.WorldEdit;
+import io.papermc.lib.PaperLib;
 import lombok.Getter;
 import lombok.NonNull;
 import org.bukkit.*;
@@ -114,23 +115,7 @@ public final class BukkitMain extends JavaPlugin implements Listener, IPlotMain
     @Override public void onEnable() {
         this.pluginName = getDescription().getName();
         PlotPlayer.registerConverter(Player.class, BukkitUtil::getPlayer);
-
+        PaperLib.suggestPaper(this);
-        if (Bukkit.getVersion().contains("git-Spigot")) {
-            // Uses System.out.println because the logger isn't initialized yet
-            System.out
-                .println("[P2] ========================== USE PAPER ==========================");
-            System.out.println("[P2] Paper offers a more complete API for us to work with");
-            System.out.println("[P2] and we may come to rely on it in the future.");
-            System.out.println("[P2] It is also recommended out of a performance standpoint as");
-            System.out
-                .println("[P2] it contains many improvements missing from Spigot and Bukkit.");
-            System.out.println("[P2] DOWNLOAD: https://papermc.io/downloads");
-            System.out.println("[P2] GUIDE: https://www.spigotmc.org/threads/21726/");
-            System.out.println("[P2] NOTE: This is only a recommendation");
-            System.out.println("[P2]       Spigot is still supported.");
-            System.out
-                .println("[P2] ===============================================================");
-        }
 
         new PlotSquared(this, "Bukkit");
 

Bukkit/src/main/java/com/github/intellectualsites/plotsquared/bukkit/events/PlayerPlotTrustedEvent.java

@@ -6,9 +6,6 @@ import org.bukkit.event.HandlerList;
 
 import java.util.UUID;
 
-/**
- *
- */
 public class PlayerPlotTrustedEvent extends PlotEvent {
 
     private static final HandlerList handlers = new HandlerList();

Bukkit/src/main/java/com/github/intellectualsites/plotsquared/bukkit/object/BukkitPlayer.java

@@ -6,12 +6,9 @@ import com.github.intellectualsites.plotsquared.plot.config.Captions;
 import com.github.intellectualsites.plotsquared.plot.object.Location;
 import com.github.intellectualsites.plotsquared.plot.object.PlotBlock;
 import com.github.intellectualsites.plotsquared.plot.object.PlotPlayer;
-import com.github.intellectualsites.plotsquared.plot.util.EconHandler;
+import com.github.intellectualsites.plotsquared.plot.util.*;
-import com.github.intellectualsites.plotsquared.plot.util.MathMan;
+import com.google.common.base.Preconditions;
-import com.github.intellectualsites.plotsquared.plot.util.PlotGameMode;
+import io.papermc.lib.PaperLib;
-import com.github.intellectualsites.plotsquared.plot.util.PlotWeather;
-import com.github.intellectualsites.plotsquared.plot.util.StringMan;
-import com.github.intellectualsites.plotsquared.plot.util.UUIDHandler;
 import org.bukkit.GameMode;
 import org.bukkit.Material;
 import org.bukkit.Sound;
@@ -20,11 +17,11 @@ import org.bukkit.entity.Player;
 import org.bukkit.event.Event;
 import org.bukkit.event.EventException;
 import org.bukkit.event.player.PlayerTeleportEvent;
-import org.bukkit.event.player.PlayerTeleportEvent.TeleportCause;
 import org.bukkit.permissions.PermissionAttachmentInfo;
 import org.bukkit.plugin.RegisteredListener;
 import org.jetbrains.annotations.NotNull;
 
+import javax.annotation.Nonnull;
 import java.util.Arrays;
 import java.util.Set;
 import java.util.UUID;
@@ -42,21 +39,23 @@ public class BukkitPlayer extends PlotPlayer {
      * <p>Please do not use this method. Instead use
      * BukkitUtil.getPlayer(Player), as it caches player objects.</p>
      *
-     * @param player
+     * @param player Bukkit player instance
      */
-    public BukkitPlayer(Player player) {
+    public BukkitPlayer(@Nonnull final Player player) {
+        Preconditions.checkNotNull(player, "Bukkit player instance cannot be null");
         this.player = player;
         super.populatePersistentMetaMap();
     }
 
-    public BukkitPlayer(Player player, boolean offline) {
+    public BukkitPlayer(@Nonnull final Player player, final boolean offline) {
+        Preconditions.checkNotNull(player, "Bukkit player instance cannot be null");
         this.player = player;
         this.offline = offline;
         super.populatePersistentMetaMap();
     }
 
     @Override public Location getLocation() {
-        Location location = super.getLocation();
+        final Location location = super.getLocation();
         return location == null ? BukkitUtil.getLocation(this.player) : location;
     }
 
@@ -71,9 +70,10 @@ public class BukkitPlayer extends PlotPlayer {
         return this.player.getLastPlayed();
     }
 
-    @Override public boolean canTeleport(Location loc) {
+    @Override public boolean canTeleport(@Nonnull final Location loc) {
-        org.bukkit.Location to = BukkitUtil.getLocation(loc);
+        Preconditions.checkNotNull(loc, "Bukkit location cannot be null");
-        org.bukkit.Location from = player.getLocation();
+        final org.bukkit.Location to = BukkitUtil.getLocation(loc);
+        final org.bukkit.Location from = player.getLocation();
         PlayerTeleportEvent event = new PlayerTeleportEvent(player, from, to);
         callEvent(event);
         if (event.isCancelled() || !event.getTo().equals(to)) {
@@ -90,32 +90,34 @@ public class BukkitPlayer extends PlotPlayer {
     }
 
     private void callEvent(final Event event) {
-        RegisteredListener[] listeners = event.getHandlers().getRegisteredListeners();
+        Preconditions.checkNotNull(event, "Event cannot be null");
-        for (RegisteredListener listener : listeners) {
+
+        final RegisteredListener[] listeners = event.getHandlers().getRegisteredListeners();
+        for (final RegisteredListener listener : listeners) {
             if (listener.getPlugin().getName().equals(PlotSquared.imp().getPluginName())) {
                 continue;
             }
             try {
                 listener.callEvent(event);
-            } catch (EventException e) {
+            } catch (final EventException e) {
                 e.printStackTrace();
             }
         }
     }
 
-    @Override public boolean hasPermission(String permission) {
+    @Override public boolean hasPermission(final String permission) {
         if (this.offline && EconHandler.manager != null) {
             return EconHandler.manager.hasPermission(getName(), permission);
         }
         return this.player.hasPermission(permission);
     }
 
-    @Override public int hasPermissionRange(String stub, int range) {
+    @Override public int hasPermissionRange(final String stub, final int range) {
         if (hasPermission(Captions.PERMISSION_ADMIN.s())) {
             return Integer.MAX_VALUE;
         }
-        String[] nodes = stub.split("\\.");
+        final String[] nodes = stub.split("\\.");
-        StringBuilder n = new StringBuilder();
+        final StringBuilder n = new StringBuilder();
         for (int i = 0; i < (nodes.length - 1); i++) {
             n.append(nodes[i]).append(".");
             if (!stub.equals(n + Captions.PERMISSION_STAR.s())) {
@@ -131,7 +133,7 @@ public class BukkitPlayer extends PlotPlayer {
         if (CHECK_EFFECTIVE) {
             boolean hasAny = false;
             String stubPlus = stub + ".";
-            Set<PermissionAttachmentInfo> effective = player.getEffectivePermissions();
+        final Set<PermissionAttachmentInfo> effective = player.getEffectivePermissions();
             if (!effective.isEmpty()) {
                 for (PermissionAttachmentInfo attach : effective) {
                     String permStr = attach.getPermission();
@@ -170,11 +172,11 @@ public class BukkitPlayer extends PlotPlayer {
         return max;
     }
 
-    @Override public boolean isPermissionSet(String permission) {
+    @Override public boolean isPermissionSet(final String permission) {
         return this.player.isPermissionSet(permission);
     }
 
-    @Override public void sendMessage(String message) {
+    @Override public void sendMessage(final String message) {
         if (!StringMan.isEqual(this.getMeta("lastMessage"), message) || (
             System.currentTimeMillis() - this.<Long>getMeta("lastMessageTime") > 5000)) {
             setMeta("lastMessage", message);
@@ -183,14 +185,13 @@ public class BukkitPlayer extends PlotPlayer {
         }
     }
 
-    @Override public void teleport(Location location) {
+    @Override public void teleport(@Nonnull final Location location) {
         if (Math.abs(location.getX()) >= 30000000 || Math.abs(location.getZ()) >= 30000000) {
             return;
         }
-        this.player.teleport(
+        final org.bukkit.Location bukkitLocation = new org.bukkit.Location(BukkitUtil.getWorld(location.getWorld()), location.getX() + 0.5,
-            new org.bukkit.Location(BukkitUtil.getWorld(location.getWorld()), location.getX() + 0.5,
+            location.getY(), location.getZ() + 0.5, location.getYaw(), location.getPitch());
-                location.getY(), location.getZ() + 0.5, location.getYaw(), location.getPitch()),
+        PaperLib.teleportAsync(player, bukkitLocation);
-            TeleportCause.COMMAND);
     }
 
     @Override public String getName() {
@@ -208,14 +209,14 @@ public class BukkitPlayer extends PlotPlayer {
         this.player.setCompassTarget(
             new org.bukkit.Location(BukkitUtil.getWorld(location.getWorld()), location.getX(),
                 location.getY(), location.getZ()));
-
     }
 
     @Override public Location getLocationFull() {
         return BukkitUtil.getLocationFull(this.player);
     }
 
-    @Override public void setWeather(PlotWeather weather) {
+    @Override public void setWeather(@Nonnull final PlotWeather weather) {
+        Preconditions.checkNotNull(weather, "Specified weather cannot be null");
         switch (weather) {
             case CLEAR:
                 this.player.setPlayerWeather(WeatherType.CLEAR);
@@ -230,7 +231,7 @@ public class BukkitPlayer extends PlotPlayer {
         }
     }
 
-    @Override public PlotGameMode getGameMode() {
+    @Nonnull @Override public PlotGameMode getGameMode() {
         switch (this.player.getGameMode()) {
             case ADVENTURE:
                 return PlotGameMode.ADVENTURE;
@@ -245,7 +246,8 @@ public class BukkitPlayer extends PlotPlayer {
         }
     }
 
-    @Override public void setGameMode(PlotGameMode gameMode) {
+    @Override public void setGameMode(@Nonnull final PlotGameMode gameMode) {
+        Preconditions.checkNotNull(gameMode, "Specified gamemode cannot be null");
         switch (gameMode) {
             case ADVENTURE:
                 this.player.setGameMode(GameMode.ADVENTURE);
@@ -263,7 +265,7 @@ public class BukkitPlayer extends PlotPlayer {
         }
     }
 
-    @Override public void setTime(long time) {
+    @Override public void setTime(final long time) {
         if (time != Long.MAX_VALUE) {
             this.player.setPlayerTime(time, false);
         } else {
@@ -279,7 +281,9 @@ public class BukkitPlayer extends PlotPlayer {
         this.player.setAllowFlight(fly);
     }
 
-    @Override public void playMusic(Location location, PlotBlock id) {
+    @Override public void playMusic(@Nonnull final Location location, @Nonnull final PlotBlock id) {
+        Preconditions.checkNotNull(location, "Specified location cannot be null");
+        Preconditions.checkNotNull(id, "Specified block cannot be null");
         if (PlotBlock.isEverything(id) || id.isAir()) {
             // Let's just stop all the discs because why not?
             for (final Sound sound : Arrays.stream(Sound.values())
@@ -294,7 +298,7 @@ public class BukkitPlayer extends PlotPlayer {
         }
     }
 
-    @Override public void kick(String message) {
+    @Override public void kick(final String message) {
         this.player.kickPlayer(message);
     }
 

Core/src/main/java/com/github/intellectualsites/plotsquared/commands/Command.java

@@ -20,6 +20,7 @@ import java.io.IOException;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.util.*;
+import java.util.concurrent.CompletableFuture;
 
 public abstract class Command {
 
@@ -72,14 +73,16 @@ public abstract class Command {
                     && types[2] == String[].class && types[3] == RunnableVal3.class
                     && types[4] == RunnableVal2.class) {
                     Command tmp = new Command(this, true) {
-                        @Override public void execute(PlotPlayer player, String[] args,
+                        @Override public CompletableFuture<Boolean> execute(PlotPlayer player, String[] args,
                             RunnableVal3<Command, Runnable, Runnable> confirm,
                             RunnableVal2<Command, CommandResult> whenDone) {
                             try {
                                 method.invoke(Command.this, this, player, args, confirm, whenDone);
+                                return CompletableFuture.completedFuture(true);
                             } catch (IllegalAccessException | InvocationTargetException e) {
                                 e.printStackTrace();
                             }
+                            return CompletableFuture.completedFuture(false);
                         }
                     };
                     tmp.init(method.getAnnotation(CommandDeclaration.class));
@@ -261,9 +264,10 @@ public abstract class Command {
      * @param player  Caller
      * @param args    Arguments
      * @param confirm Instance, Success, Failure
-     * @return
+     * @return CompletableFuture true if the command executed fully, false in
+     * any other case
      */
-    public void execute(PlotPlayer player, String[] args,
+    public CompletableFuture<Boolean> execute(PlotPlayer player, String[] args,
         RunnableVal3<Command, Runnable, Runnable> confirm,
         RunnableVal2<Command, CommandResult> whenDone) throws CommandException {
         if (args.length == 0 || args[0] == null) {
@@ -272,18 +276,18 @@ public abstract class Command {
             } else {
                 Captions.COMMAND_SYNTAX.send(player, getUsage());
             }
-            return;
+            return CompletableFuture.completedFuture(false);
         }
         if (this.allCommands.isEmpty()) {
             player.sendMessage(
                 "Not Implemented: https://github.com/IntellectualSites/PlotSquared/issues/new");
-            return;
+            return CompletableFuture.completedFuture(false);
         }
         Command cmd = getCommand(args[0]);
         if (cmd == null) {
             if (this.parent != null) {
                 Captions.COMMAND_SYNTAX.send(player, getUsage());
-                return;
+                return CompletableFuture.completedFuture(false);
             }
             // Help command
             try {
@@ -293,7 +297,7 @@ public abstract class Command {
                 // This will default certain syntax to the help command
                 // e.g. /plot, /plot 1, /plot claiming
                 MainCommand.getInstance().help.execute(player, args, null, null);
-                return;
+                return CompletableFuture.completedFuture(false);
             } catch (IllegalArgumentException ignored) {
             }
             // Command recommendation
@@ -302,13 +306,16 @@ public abstract class Command {
             if (commands.isEmpty()) {
                 MainUtil.sendMessage(player, Captions.DID_YOU_MEAN,
                     MainCommand.getInstance().help.getUsage());
-                return;
+                return CompletableFuture.completedFuture(false);
             }
-            String[] allargs =
+            HashSet<String> setArgs = new HashSet<>(args.length);
-                Arrays.stream(args).map(String::toLowerCase).distinct().toArray(String[]::new);
+            for (String arg : args) {
+                setArgs.add(arg.toLowerCase());
+            }
+            String[] allArgs = setArgs.toArray(new String[0]);
             int best = 0;
             for (Command current : commands) {
-                int match = getMatch(allargs, current);
+                int match = getMatch(allArgs, current);
                 if (match > best) {
                     cmd = current;
                 }
@@ -317,17 +324,18 @@ public abstract class Command {
                 cmd = new StringComparison<>(args[0], this.allCommands).getMatchObject();
             }
             MainUtil.sendMessage(player, Captions.DID_YOU_MEAN, cmd.getUsage());
-            return;
+            return CompletableFuture.completedFuture(false);
         }
         String[] newArgs = Arrays.copyOfRange(args, 1, args.length);
         if (!cmd.checkArgs(player, newArgs) || !cmd.canExecute(player, true)) {
-            return;
+            return CompletableFuture.completedFuture(false);
         }
         try {
             cmd.execute(player, newArgs, confirm, whenDone);
         } catch (CommandException e) {
             e.perform(player);
         }
+        return CompletableFuture.completedFuture(true);
     }
 
     public boolean checkArgs(CommandCaller player, String[] args) {

Core/src/main/java/com/github/intellectualsites/plotsquared/plot/commands/Add.java

@@ -15,6 +15,7 @@ import com.github.intellectualsites.plotsquared.plot.util.Permissions;
 import java.util.Iterator;
 import java.util.Set;
 import java.util.UUID;
+import java.util.concurrent.CompletableFuture;
 
 @CommandDeclaration(command = "add",
     description = "Allow a user to build in a plot while you are online",
@@ -25,7 +26,7 @@ import java.util.UUID;
         super(MainCommand.getInstance(), true);
     }
 
-    @Override public void execute(final PlotPlayer player, String[] args,
+    @Override public CompletableFuture<Boolean> execute(final PlotPlayer player, String[] args,
         RunnableVal3<Command, Runnable, Runnable> confirm,
         RunnableVal2<Command, CommandResult> whenDone) throws CommandException {
         final Plot plot = check(player.getCurrentPlot(), Captions.NOT_IN_PLOT);
@@ -78,5 +79,7 @@ import java.util.UUID;
                 MainUtil.sendMessage(player, Captions.MEMBER_ADDED);
             }
         }, null);
+
+        return CompletableFuture.completedFuture(true);
     }
 }

Core/src/main/java/com/github/intellectualsites/plotsquared/plot/commands/Buy.java

@@ -14,6 +14,7 @@ import com.github.intellectualsites.plotsquared.plot.util.UUIDHandler;
 
 import java.util.Optional;
 import java.util.Set;
+import java.util.concurrent.CompletableFuture;
 
 @CommandDeclaration(command = "buy", description = "Buy the plot you are standing on",
     usage = "/plot buy", permission = "plots.buy", category = CommandCategory.CLAIMING,
@@ -23,7 +24,7 @@ import java.util.Set;
         super(MainCommand.getInstance(), true);
     }
 
-    @Override public void execute(final PlotPlayer player, String[] args,
+    @Override public CompletableFuture<Boolean> execute(final PlotPlayer player, String[] args,
         RunnableVal3<Command, Runnable, Runnable> confirm,
         final RunnableVal2<Command, CommandResult> whenDone) {
 
@@ -65,5 +66,6 @@ import java.util.Set;
             player.deposit(price);
             whenDone.run(Buy.this, CommandResult.FAILURE);
         });
+        return CompletableFuture.completedFuture(true);
     }
 }

Core/src/main/java/com/github/intellectualsites/plotsquared/plot/commands/Clear.java

@@ -14,6 +14,8 @@ import com.github.intellectualsites.plotsquared.plot.util.MainUtil;
 import com.github.intellectualsites.plotsquared.plot.util.Permissions;
 import com.github.intellectualsites.plotsquared.plot.util.block.GlobalBlockQueue;
 
+import java.util.concurrent.CompletableFuture;
+
 @CommandDeclaration(command = "clear", description = "Clear the plot you stand on",
     permission = "plots.clear", category = CommandCategory.APPEARANCE, usage = "/plot clear",
     aliases = "reset", confirmation = true) public class Clear extends Command {
@@ -25,7 +27,7 @@ import com.github.intellectualsites.plotsquared.plot.util.block.GlobalBlockQueue
         super(MainCommand.getInstance(), true);
     }
 
-    @Override public void execute(final PlotPlayer player, String[] args,
+    @Override public CompletableFuture<Boolean> execute(final PlotPlayer player, String[] args,
         RunnableVal3<Command, Runnable, Runnable> confirm,
         RunnableVal2<Command, CommandResult> whenDone) throws CommandException {
         checkTrue(args.length == 0, Captions.COMMAND_SYNTAX, getUsage());
@@ -59,5 +61,6 @@ import com.github.intellectualsites.plotsquared.plot.util.block.GlobalBlockQueue
                 plot.addRunning();
             }
         }, null);
+        return CompletableFuture.completedFuture(true);
     }
 }

Core/src/main/java/com/github/intellectualsites/plotsquared/plot/commands/DebugExec.java

@@ -32,6 +32,7 @@ import java.util.Date;
 import java.util.HashMap;
 import java.util.List;
 import java.util.UUID;
+import java.util.concurrent.CompletableFuture;
 
 @CommandDeclaration(command = "debugexec", permission = "plots.admin",
     description = "Mutli-purpose debug command", aliases = {"exec", "$"},
@@ -284,7 +285,7 @@ import java.util.UUID;
                             System.getProperty("line.separator"));
                         new Command(MainCommand.getInstance(), true, args[1].split("\\.")[0], null,
                             RequiredType.NONE, CommandCategory.DEBUG) {
-                            @Override public void execute(PlotPlayer player, String[] args,
+                            @Override public CompletableFuture<Boolean> execute(PlotPlayer player, String[] args,
                                 RunnableVal3<Command, Runnable, Runnable> confirm,
                                 RunnableVal2<Command, CommandResult> whenDone) {
                                 try {
@@ -295,6 +296,7 @@ import java.util.UUID;
                                     e.printStackTrace();
                                     MainUtil.sendMessage(player, Captions.COMMAND_WENT_WRONG);
                                 }
+                                return CompletableFuture.completedFuture(true);
                             }
                         };
                         return true;

Core/src/main/java/com/github/intellectualsites/plotsquared/plot/commands/DebugImportWorlds.java

@@ -16,6 +16,7 @@ import com.google.common.base.Charsets;
 
 import java.io.File;
 import java.util.UUID;
+import java.util.concurrent.CompletableFuture;
 
 @CommandDeclaration(command = "debugimportworlds", permission = "plots.admin",
     description = "Import worlds by player name", requiredType = RequiredType.CONSOLE,
@@ -24,14 +25,14 @@ import java.util.UUID;
         super(MainCommand.getInstance(), true);
     }
 
-    @Override public void execute(PlotPlayer player, String[] args,
+    @Override public CompletableFuture<Boolean> execute(PlotPlayer player, String[] args,
         RunnableVal3<Command, Runnable, Runnable> confirm,
         RunnableVal2<Command, CommandResult> whenDone) throws CommandException {
         // UUID.nameUUIDFromBytes(("OfflinePlayer:" + player.getName()).getBytes(Charsets.UTF_8))
         PlotAreaManager pam = PlotSquared.get().getPlotAreaManager();
         if (!(pam instanceof SinglePlotAreaManager)) {
             player.sendMessage("Must be a single plot area!");
-            return;
+            return CompletableFuture.completedFuture(false);
         }
         SinglePlotArea area = ((SinglePlotAreaManager) pam).getArea();
         PlotId id = new PlotId(0, 0);
@@ -64,5 +65,6 @@ import java.util.UUID;
             }
         }
         player.sendMessage("Done!");
+        return CompletableFuture.completedFuture(true);
     }
 }

Core/src/main/java/com/github/intellectualsites/plotsquared/plot/commands/Grant.java

@@ -14,6 +14,7 @@ import com.github.intellectualsites.plotsquared.plot.util.Permissions;
 import com.github.intellectualsites.plotsquared.plot.util.UUIDHandler;
 
 import java.util.UUID;
+import java.util.concurrent.CompletableFuture;
 
 @CommandDeclaration(command = "grant", category = CommandCategory.CLAIMING,
     usage = "/plot grant <check|add> [player]", permission = "plots.grant",
@@ -23,7 +24,7 @@ import java.util.UUID;
         super(MainCommand.getInstance(), true);
     }
 
-    @Override public void execute(final PlotPlayer player, String[] args,
+    @Override public CompletableFuture<Boolean> execute(final PlotPlayer player, String[] args,
         RunnableVal3<Command, Runnable, Runnable> confirm,
         RunnableVal2<Command, CommandResult> whenDone) throws CommandException {
         checkTrue(args.length >= 1 && args.length <= 2, Captions.COMMAND_SYNTAX, getUsage());
@@ -33,7 +34,7 @@ import java.util.UUID;
             case "check":
                 if (!Permissions.hasPermission(player, Captions.PERMISSION_GRANT.f(arg0))) {
                     Captions.NO_PERMISSION.send(player, Captions.PERMISSION_GRANT.f(arg0));
-                    return;
+                    return CompletableFuture.completedFuture(false);
                 }
                 if (args.length > 2) {
                     break;
@@ -46,7 +47,7 @@ import java.util.UUID;
                 }
                 if (uuid == null) {
                     Captions.INVALID_PLAYER.send(player, args[1]);
-                    return;
+                    return CompletableFuture.completedFuture(false);
                 }
                 MainUtil.getPersistentMeta(uuid, "grantedPlots", new RunnableVal<byte[]>() {
                     @Override public void run(byte[] array) {
@@ -77,7 +78,9 @@ import java.util.UUID;
                         }
                     }
                 });
+                return CompletableFuture.completedFuture(true);
         }
         Captions.COMMAND_SYNTAX.send(player, getUsage());
+        return CompletableFuture.completedFuture(true);
     }
 }

Core/src/main/java/com/github/intellectualsites/plotsquared/plot/commands/Help.java

@@ -12,6 +12,8 @@ import com.github.intellectualsites.plotsquared.plot.util.MathMan;
 import com.github.intellectualsites.plotsquared.plot.util.StringMan;
 import com.github.intellectualsites.plotsquared.plot.util.helpmenu.HelpMenu;
 
+import java.util.concurrent.CompletableFuture;
+
 @CommandDeclaration(command = "help", description = "Get this help menu", aliases = {"he", "?"},
     category = CommandCategory.INFO, usage = "help [category|#]", permission = "plots.use")
 public class Help extends Command {
@@ -23,44 +25,44 @@ public class Help extends Command {
         return true;
     }
 
-    @Override public void execute(PlotPlayer player, String[] args,
+    @Override public CompletableFuture<Boolean> execute(PlotPlayer player, String[] args,
         RunnableVal3<Command, Runnable, Runnable> confirm,
         RunnableVal2<Command, CommandResult> whenDone) {
         switch (args.length) {
             case 0:
-                displayHelp(player, null, 0);
+                return displayHelp(player, null, 0);
-                return;
             case 1:
                 if (MathMan.isInteger(args[0])) {
                     try {
-                        displayHelp(player, null, Integer.parseInt(args[0]));
+                        return displayHelp(player, null, Integer.parseInt(args[0]));
                     } catch (NumberFormatException ignored) {
-                        displayHelp(player, null, 1);
+                        return displayHelp(player, null, 1);
                     }
                 } else {
-                    displayHelp(player, args[0], 1);
+                    return displayHelp(player, args[0], 1);
                 }
-                return;
             case 2:
                 if (MathMan.isInteger(args[1])) {
                     try {
-                        displayHelp(player, args[0], Integer.parseInt(args[1]));
+                        return displayHelp(player, args[0], Integer.parseInt(args[1]));
                     } catch (NumberFormatException ignored) {
-                        displayHelp(player, args[0], 1);
+                        return displayHelp(player, args[0], 1);
                     }
                 }
-                return;
+                return CompletableFuture.completedFuture(false);
             default:
                 Captions.COMMAND_SYNTAX.send(player, getUsage());
         }
+        return CompletableFuture.completedFuture(true);
     }
 
-    public void displayHelp(CommandCaller player, String cat, int page) {
+    public CompletableFuture<Boolean> displayHelp(final CommandCaller player, final String catRaw, final int page) {
+        return CompletableFuture.supplyAsync(() -> {
+            String cat = catRaw;
+
             CommandCategory catEnum = null;
             if (cat != null) {
-            if (StringMan.isEqualIgnoreCase(cat, "all")) {
+                if (!StringMan.isEqualIgnoreCase(cat, "all")) {
-                catEnum = null;
-            } else {
                     for (CommandCategory c : CommandCategory.values()) {
                         if (StringMan.isEqualIgnoreCaseToAny(cat, c.name(), c.toString())) {
                             catEnum = c;
@@ -77,18 +79,19 @@ public class Help extends Command {
                 StringBuilder builder = new StringBuilder();
             builder.append(Captions.HELP_HEADER.s());
                 for (CommandCategory c : CommandCategory.values()) {
-                builder.append("\n" + StringMan
+                    builder.append("\n").append(StringMan
-                    .replaceAll(Captions.HELP_INFO_ITEM.s(), "%category%",
+                        .replaceAll(Captions.HELP_INFO_ITEM.s(), "%category%", c.toString().toLowerCase(),
-                        c.toString().toLowerCase(), "%category_desc%", c.toString()));
+                            "%category_desc%", c.toString()));
                 }
             builder.append("\n").append(Captions.HELP_INFO_ITEM.s().replaceAll("%category%", "all")
                 .replaceAll("%category_desc%", Captions.HELP_DISPLAY_ALL_COMMANDS.s()));
             builder.append("\n" + Captions.HELP_FOOTER.s());
                 MainUtil.sendMessage(player, builder.toString(), false);
-            return;
+                return true;
             }
-        page--;
             new HelpMenu(player).setCategory(catEnum).getCommands().generateMaxPages()
-            .generatePage(page, getParent().toString()).render();
+                .generatePage(page - 1, getParent().toString()).render();
+            return true;
+        });
     }
 }

Core/src/main/java/com/github/intellectualsites/plotsquared/plot/commands/Leave.java

@@ -11,6 +11,7 @@ import com.github.intellectualsites.plotsquared.plot.util.EventUtil;
 import com.github.intellectualsites.plotsquared.plot.util.MainUtil;
 
 import java.util.UUID;
+import java.util.concurrent.CompletableFuture;
 
 @CommandDeclaration(command = "leave",
     description = "Removes self from being trusted or a member of the plot",
@@ -20,7 +21,7 @@ import java.util.UUID;
         super(MainCommand.getInstance(), true);
     }
 
-    @Override public void execute(PlotPlayer player, String[] args,
+    @Override public CompletableFuture<Boolean> execute(PlotPlayer player, String[] args,
         RunnableVal3<Command, Runnable, Runnable> confirm,
         RunnableVal2<Command, CommandResult> whenDone) throws CommandException {
         final Plot plot = check(player.getCurrentPlot(), Captions.NOT_IN_PLOT);
@@ -44,5 +45,6 @@ import java.util.UUID;
                 MainUtil.sendMessage(player, Captions.REMOVED_PLAYERS, 1);
             }
         }
+        return CompletableFuture.completedFuture(true);
     }
 }

Core/src/main/java/com/github/intellectualsites/plotsquared/plot/commands/MainCommand.java

@@ -11,6 +11,7 @@ import com.github.intellectualsites.plotsquared.plot.util.EconHandler;
 import com.github.intellectualsites.plotsquared.plot.util.Permissions;
 
 import java.util.Arrays;
+import java.util.concurrent.CompletableFuture;
 
 /**
  * PlotSquared command class.
@@ -176,6 +177,8 @@ public class MainCommand extends Command {
                 @Override public void run(Command cmd, CommandResult result) {
                     // Post command stuff!?
                 }
+            }).thenAccept(result -> {
+                // TODO: Something with the command result
             });
         } catch (CommandException e) {
             e.perform(player);
@@ -184,7 +187,7 @@ public class MainCommand extends Command {
         return true;
     }
 
-    @Override public void execute(final PlotPlayer player, String[] args,
+    @Override public CompletableFuture<Boolean> execute(final PlotPlayer player, String[] args,
         RunnableVal3<Command, Runnable, Runnable> confirm,
         RunnableVal2<Command, CommandResult> whenDone) {
         // Clear perm caching //
@@ -215,18 +218,14 @@ public class MainCommand extends Command {
                 args = Arrays.copyOfRange(args, 1, args.length);
             }
             if (args.length >= 2 && !args[0].isEmpty() && args[0].charAt(0) == '-') {
-                switch (args[0].substring(1)) {
+                if ("f".equals(args[0].substring(1))) {
-                    case "f":
                     confirm = new RunnableVal3<Command, Runnable, Runnable>() {
-                            @Override
+                        @Override public void run(Command cmd, Runnable success, Runnable failure) {
-                            public void run(Command cmd, Runnable success, Runnable failure) {
                             if (EconHandler.manager != null) {
                                 PlotArea area = player.getApplicablePlotArea();
                                 if (area != null) {
-                                        Expression<Double> priceEval =
+                                    Expression<Double> priceEval = area.PRICES.get(cmd.getFullId());
-                                            area.PRICES.get(cmd.getFullId());
+                                    Double price = priceEval != null ? priceEval.evaluate(0d) : 0d;
-                                        Double price =
-                                            priceEval != null ? priceEval.evaluate(0d) : 0d;
                                     if (price != 0d
                                         && EconHandler.manager.getMoney(player) < price) {
                                         if (failure != null) {
@@ -242,10 +241,9 @@ public class MainCommand extends Command {
                         }
                     };
                     args = Arrays.copyOfRange(args, 1, args.length);
-                        break;
+                } else {
-                    default:
                     Captions.INVALID_COMMAND_FLAG.send(player);
-                        return;
+                    return CompletableFuture.completedFuture(false);
                 }
             }
         }
@@ -275,6 +273,7 @@ public class MainCommand extends Command {
                 player.setMeta(PlotPlayer.META_LAST_PLOT, plot);
             }
         }
+        return CompletableFuture.completedFuture(true);
     }
 
     @Override public boolean canExecute(CommandCaller player, boolean message) {

Core/src/main/java/com/github/intellectualsites/plotsquared/plot/commands/Near.java

@@ -9,6 +9,8 @@ import com.github.intellectualsites.plotsquared.plot.object.RunnableVal2;
 import com.github.intellectualsites.plotsquared.plot.object.RunnableVal3;
 import com.github.intellectualsites.plotsquared.plot.util.StringMan;
 
+import java.util.concurrent.CompletableFuture;
+
 @CommandDeclaration(command = "near", aliases = "n", description = "Display nearby players",
     usage = "/plot near", category = CommandCategory.INFO, requiredType = RequiredType.PLAYER)
 public class Near extends Command {
@@ -16,10 +18,11 @@ public class Near extends Command {
         super(MainCommand.getInstance(), true);
     }
 
-    @Override public void execute(PlotPlayer player, String[] args,
+    @Override public CompletableFuture<Boolean> execute(PlotPlayer player, String[] args,
         RunnableVal3<Command, Runnable, Runnable> confirm,
         RunnableVal2<Command, CommandResult> whenDone) throws CommandException {
         final Plot plot = check(player.getCurrentPlot(), Captions.NOT_IN_PLOT);
         Captions.PLOT_NEAR.send(player, StringMan.join(plot.getPlayersInPlot(), ", "));
+        return CompletableFuture.completedFuture(true);
     }
 }

Core/src/main/java/com/github/intellectualsites/plotsquared/plot/commands/Relight.java

@@ -7,7 +7,7 @@ import com.github.intellectualsites.plotsquared.plot.object.*;
 import com.github.intellectualsites.plotsquared.plot.util.ChunkManager;
 import com.github.intellectualsites.plotsquared.plot.util.block.LocalBlockQueue;
 
-import java.util.HashSet;
+import java.util.concurrent.CompletableFuture;
 
 @CommandDeclaration(command = "relight", description = "Relight your plot", usage = "/plot relight",
     category = CommandCategory.DEBUG) public class Relight extends Command {
@@ -15,25 +15,24 @@ import java.util.HashSet;
         super(MainCommand.getInstance(), true);
     }
 
-    @Override public void execute(final PlotPlayer player, String[] args,
+    @Override public CompletableFuture<Boolean> execute(final PlotPlayer player, String[] args,
         RunnableVal3<Command, Runnable, Runnable> confirm,
         RunnableVal2<Command, CommandResult> whenDone) {
         final Plot plot = player.getCurrentPlot();
         if (plot == null) {
             Captions.NOT_IN_PLOT.send(player);
-            return;
+            return CompletableFuture.completedFuture(false);
         }
-        HashSet<RegionWrapper> regions = plot.getRegions();
         final LocalBlockQueue queue = plot.getArea().getQueue(false);
         ChunkManager.chunkTask(plot, new RunnableVal<int[]>() {
             @Override public void run(int[] value) {
                 queue.fixChunkLighting(value[0], value[1]);
             }
-        }, new Runnable() {
+        }, () -> {
-            @Override public void run() {
             plot.refreshChunks();
             Captions.SET_BLOCK_ACTION_FINISHED.send(player);
-            }
         }, 5);
+
+        return CompletableFuture.completedFuture(true);
     }
 }

Core/src/main/java/com/github/intellectualsites/plotsquared/plot/commands/SubCommand.java

@@ -7,6 +7,8 @@ import com.github.intellectualsites.plotsquared.plot.object.PlotPlayer;
 import com.github.intellectualsites.plotsquared.plot.object.RunnableVal2;
 import com.github.intellectualsites.plotsquared.plot.object.RunnableVal3;
 
+import java.util.concurrent.CompletableFuture;
+
 /**
  * SubCommand class
  *
@@ -28,10 +30,10 @@ public abstract class SubCommand extends Command {
         return true;
     }
 
-    @Override public void execute(PlotPlayer player, String[] args,
+    @Override public CompletableFuture<Boolean> execute(PlotPlayer player, String[] args,
         RunnableVal3<Command, Runnable, Runnable> confirm,
         RunnableVal2<Command, CommandResult> whenDone) {
-        onCommand(player, args);
+        return CompletableFuture.completedFuture(onCommand(player, args));
     }
 
     public abstract boolean onCommand(PlotPlayer player, String[] args);

Core/src/main/java/com/github/intellectualsites/plotsquared/plot/commands/Trust.java

@@ -15,6 +15,7 @@ import com.github.intellectualsites.plotsquared.plot.util.Permissions;
 import java.util.Iterator;
 import java.util.Set;
 import java.util.UUID;
+import java.util.concurrent.CompletableFuture;
 
 @CommandDeclaration(command = "trust", aliases = {"t"}, requiredType = RequiredType.PLAYER,
     usage = "/plot trust <player>",
@@ -25,7 +26,7 @@ import java.util.UUID;
         super(MainCommand.getInstance(), true);
     }
 
-    @Override public void execute(final PlotPlayer player, String[] args,
+    @Override public CompletableFuture<Boolean> execute(final PlotPlayer player, String[] args,
         RunnableVal3<Command, Runnable, Runnable> confirm,
         RunnableVal2<Command, CommandResult> whenDone) throws CommandException {
         final Plot currentPlot = player.getCurrentPlot();
@@ -81,5 +82,7 @@ import java.util.UUID;
                 MainUtil.sendMessage(player, Captions.TRUSTED_ADDED);
             }
         }, null);
+
+        return CompletableFuture.completedFuture(true);
     }
 }

Core/src/main/java/com/github/intellectualsites/plotsquared/plot/commands/Visit.java

@@ -12,6 +12,7 @@ import com.github.intellectualsites.plotsquared.plot.util.Permissions;
 import com.github.intellectualsites.plotsquared.plot.util.UUIDHandler;
 
 import java.util.*;
+import java.util.concurrent.CompletableFuture;
 
 @CommandDeclaration(command = "visit", permission = "plots.visit",
     description = "Visit someones plot", usage = "/plot visit [<player>|<alias>|<world>|<id>] [#]",
@@ -26,7 +27,7 @@ import java.util.*;
         return tabOf(player, args, space, getUsage());
     }
 
-    @Override public void execute(final PlotPlayer player, String[] args,
+    @Override public CompletableFuture<Boolean> execute(final PlotPlayer player, String[] args,
         RunnableVal3<Command, Runnable, Runnable> confirm,
         final RunnableVal2<Command, CommandResult> whenDone) throws CommandException {
         if (args.length == 1 && args[0].contains(":")) {
@@ -41,7 +42,7 @@ import java.util.*;
                 if (!MathMan.isInteger(args[1])) {
                     Captions.NOT_VALID_NUMBER.send(player, "(1, ∞)");
                     Captions.COMMAND_SYNTAX.send(player, getUsage());
-                    return;
+                    return CompletableFuture.completedFuture(false);
                 }
                 page = Integer.parseInt(args[2]);
             case 2:
@@ -50,12 +51,12 @@ import java.util.*;
                     if (sortByArea == null) {
                         Captions.NOT_VALID_NUMBER.send(player, "(1, ∞)");
                         Captions.COMMAND_SYNTAX.send(player, getUsage());
-                        return;
+                        return CompletableFuture.completedFuture(false);
                     }
                     UUID user = UUIDHandler.getUUIDFromString(args[0]);
                     if (user == null) {
                         Captions.COMMAND_SYNTAX.send(player, getUsage());
-                        return;
+                        return CompletableFuture.completedFuture(false);
                     }
                     unsorted = PlotSquared.get().getBasePlots(user);
                     shouldSortByArea = true;
@@ -93,7 +94,7 @@ import java.util.*;
         }
         if (unsorted == null || unsorted.isEmpty()) {
             Captions.FOUND_NO_PLOTS.send(player);
-            return;
+            return CompletableFuture.completedFuture(false);
         }
         unsorted = new ArrayList<>(unsorted);
         if (unsorted.size() > 1) {
@@ -101,7 +102,7 @@ import java.util.*;
         }
         if (page < 1 || page > unsorted.size()) {
             Captions.NOT_VALID_NUMBER.send(player, "(1, " + unsorted.size() + ")");
-            return;
+            return CompletableFuture.completedFuture(false);
         }
         List<Plot> plots;
         if (shouldSortByArea) {
@@ -114,23 +115,23 @@ import java.util.*;
         if (!plot.hasOwner()) {
             if (!Permissions.hasPermission(player, Captions.PERMISSION_VISIT_UNOWNED)) {
                 Captions.NO_PERMISSION.send(player, Captions.PERMISSION_VISIT_UNOWNED);
-                return;
+                return CompletableFuture.completedFuture(false);
             }
         } else if (plot.isOwner(player.getUUID())) {
             if (!Permissions.hasPermission(player, Captions.PERMISSION_VISIT_OWNED) && !Permissions
                 .hasPermission(player, Captions.PERMISSION_HOME)) {
                 Captions.NO_PERMISSION.send(player, Captions.PERMISSION_VISIT_OWNED);
-                return;
+                return CompletableFuture.completedFuture(false);
             }
         } else if (plot.isAdded(player.getUUID())) {
             if (!Permissions.hasPermission(player, Captions.PERMISSION_SHARED)) {
                 Captions.NO_PERMISSION.send(player, Captions.PERMISSION_SHARED);
-                return;
+                return CompletableFuture.completedFuture(false);
             }
         } else {
             if (!Permissions.hasPermission(player, Captions.PERMISSION_VISIT_OTHER)) {
                 Captions.NO_PERMISSION.send(player, Captions.PERMISSION_VISIT_OTHER);
-                return;
+                return CompletableFuture.completedFuture(false);
             }
         }
         confirm.run(this, () -> {
@@ -140,6 +141,8 @@ import java.util.*;
                 whenDone.run(Visit.this, CommandResult.FAILURE);
             }
         }, () -> whenDone.run(Visit.this, CommandResult.FAILURE));
+
+        return CompletableFuture.completedFuture(true);
     }
 
 }

Core/src/main/java/com/github/intellectualsites/plotsquared/plot/object/ConsolePlayer.java

@@ -34,7 +34,7 @@ public class ConsolePlayer extends PlotPlayer {
         return instance;
     }
 
-    @Override public boolean canTeleport(Location loc) {
+    @Override public boolean canTeleport(@Nonnull Location loc) {
         return true;
     }
 
@@ -100,14 +100,14 @@ public class ConsolePlayer extends PlotPlayer {
         return RequiredType.CONSOLE;
     }
 
-    @Override public void setWeather(PlotWeather weather) {
+    @Override public void setWeather(@Nonnull PlotWeather weather) {
     }
 
-    @Override public PlotGameMode getGameMode() {
+    @Nonnull @Override public PlotGameMode getGameMode() {
         return PlotGameMode.NOT_SET;
     }
 
-    @Override public void setGameMode(PlotGameMode gameMode) {
+    @Override public void setGameMode(@Nonnull PlotGameMode gameMode) {
     }
 
     @Override public void setTime(long time) {
@@ -120,7 +120,7 @@ public class ConsolePlayer extends PlotPlayer {
     @Override public void setFlight(boolean fly) {
     }
 
-    @Override public void playMusic(Location location, PlotBlock id) {
+    @Override public void playMusic(@Nonnull Location location, @Nonnull PlotBlock id) {
     }
 
     @Override public void kick(String message) {

Core/src/main/java/com/github/intellectualsites/plotsquared/plot/object/PlotPlayer.java

@@ -12,6 +12,7 @@ import com.github.intellectualsites.plotsquared.plot.object.worlds.SinglePlotAre
 import com.github.intellectualsites.plotsquared.plot.object.worlds.SinglePlotAreaManager;
 import com.github.intellectualsites.plotsquared.plot.util.*;
 import com.github.intellectualsites.plotsquared.plot.util.expiry.ExpireManager;
+import com.google.common.base.Preconditions;
 import lombok.NonNull;
 
 import javax.annotation.Nonnull;
@@ -333,8 +334,9 @@ public abstract class PlotPlayer implements CommandCaller, OfflinePlotPlayer {
      */
     @Override @Nonnull public abstract UUID getUUID();
 
-    public boolean canTeleport(Location loc) {
+    public boolean canTeleport(@Nonnull final Location loc) {
-        Location current = getLocationFull();
+        Preconditions.checkNotNull(loc, "Specified location cannot be null");
+        final Location current = getLocationFull();
         teleport(loc);
         boolean result = true;
         if (!getLocation().equals(loc)) {
@@ -416,21 +418,21 @@ public abstract class PlotPlayer implements CommandCaller, OfflinePlotPlayer {
      *
      * @param weather the weather visible to the player
      */
-    public abstract void setWeather(PlotWeather weather);
+    public abstract void setWeather(@Nonnull PlotWeather weather);
 
     /**
      * Get this player's gamemode.
      *
      * @return the gamemode of the player.
      */
-    public abstract PlotGameMode getGameMode();
+    @Nonnull public abstract PlotGameMode getGameMode();
 
     /**
      * Set this player's gameMode.
      *
      * @param gameMode the gamemode to set
      */
-    public abstract void setGameMode(PlotGameMode gameMode);
+    public abstract void setGameMode(@Nonnull PlotGameMode gameMode);
 
     /**
      * Set this player's local time (ticks).
@@ -459,7 +461,7 @@ public abstract class PlotPlayer implements CommandCaller, OfflinePlotPlayer {
      * @param location where to play the music
      * @param id       the record item id
      */
-    public abstract void playMusic(Location location, PlotBlock id);
+    public abstract void playMusic(@Nonnull Location location, @Nonnull PlotBlock id);
 
     /**
      * Check if this player is banned.