Cj/async teleport (#34)

* implement teleportAsync compatibility

* try to use Paper's built in teleportAsync even if we use bukkit compatibility

* grammar fix

* increment version to 0.6.0

README.md

@@ -25,7 +25,7 @@ Spigot's scheduler, `BukkitRunnable`. This adds support for practically any serv
 <dependency>
     <groupId>com.cjcrafter</groupId>
     <artifactId>foliascheduler</artifactId>
-    <version>0.5.0</version>
+    <version>0.6.0</version>
 </dependency>
 ```
 
@@ -37,7 +37,7 @@ Spigot's scheduler, `BukkitRunnable`. This adds support for practically any serv
     <dependency>
         <groupId>com.cjcrafter</groupId>
         <artifactId>foliascheduler</artifactId>
-        <version>0.5.0</version>
+        <version>0.6.0</version>
     </dependency>
 </dependencies>
 
@@ -76,7 +76,7 @@ repositories {
 }
 
 dependencies {
-    implementation("com.cjcrafter:foliascheduler:0.5.0")
+    implementation("com.cjcrafter:foliascheduler:0.6.0")
 }
 ```
 
@@ -97,7 +97,7 @@ repositories {
 
 dependencies {
     // TODO add your version of Spigot/Paper here
-    implementation("com.cjcrafter:foliascheduler:0.5.0")
+    implementation("com.cjcrafter:foliascheduler:0.6.0")
 }
 
 // See https://github.com/Minecrell/plugin-yml

build.gradle.kts

@@ -7,7 +7,7 @@ plugins {
 }
 
 group = "com.cjcrafter"
-version = "0.5.0"
+version = "0.6.0"
 
 val githubOwner = "CJCrafter"
 val githubRepo = "FoliaScheduler"

platforms/folia/src/main/java/com/cjcrafter/foliascheduler/folia/FoliaServer.java

@@ -10,10 +10,13 @@
 import org.bukkit.World;
 import org.bukkit.block.Block;
 import org.bukkit.entity.Entity;
+import org.bukkit.event.player.PlayerTeleportEvent;
 import org.bukkit.plugin.Plugin;
 import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
 
+import java.util.concurrent.CompletableFuture;
+
 @ApiStatus.Internal
 public class FoliaServer implements ServerImplementation {
 
@@ -88,4 +91,9 @@ public void cancelTasks() {
         globalScheduler.cancelTasks();
         asyncScheduler.cancelTasks();
     }
+
+    @Override
+    public @NotNull CompletableFuture<Boolean> teleportAsync(@NotNull Entity entity, @NotNull Location location, @NotNull PlayerTeleportEvent.TeleportCause cause) {
+        return entity.teleportAsync(location, cause);
+    }
 }

platforms/spigot/src/main/java/com/cjcrafter/foliascheduler/bukkit/BukkitServer.java

@@ -5,13 +5,23 @@
 import com.cjcrafter.foliascheduler.GlobalSchedulerImplementation;
 import com.cjcrafter.foliascheduler.RegionSchedulerImplementation;
 import com.cjcrafter.foliascheduler.ServerImplementation;
+import com.cjcrafter.foliascheduler.util.MethodInvoker;
+import com.cjcrafter.foliascheduler.util.ReflectionUtil;
+import com.cjcrafter.foliascheduler.util.WrappedReflectiveOperationException;
 import org.bukkit.Location;
 import org.bukkit.World;
 import org.bukkit.block.Block;
 import org.bukkit.entity.Entity;
+import org.bukkit.event.player.PlayerTeleportEvent;
 import org.bukkit.plugin.Plugin;
 import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.lang.reflect.Method;
+import java.util.Objects;
+import java.util.concurrent.CompletableFuture;
+import java.util.logging.Level;
 
 @ApiStatus.Internal
 public class BukkitServer implements ServerImplementation {
@@ -21,12 +31,21 @@ public class BukkitServer implements ServerImplementation {
     private final @NotNull BukkitRegionScheduler region;
     private final @NotNull BukkitAsyncScheduler async;
 
+    // On Paper servers, the teleportAsync method is supported back to 1.13
+    private @Nullable MethodInvoker teleportAsyncMethod;
+
     @ApiStatus.Internal
     public BukkitServer(@NotNull Plugin owningPlugin) {
         this.owningPlugin = owningPlugin;
         this.sync = new BukkitSyncScheduler(owningPlugin);
         this.region = new BukkitRegionScheduler(owningPlugin);
         this.async = new BukkitAsyncScheduler(owningPlugin);
+
+        try {
+            teleportAsyncMethod = ReflectionUtil.getMethod(Entity.class, "teleportAsync", Location.class, PlayerTeleportEvent.TeleportCause.class);
+        } catch (WrappedReflectiveOperationException ignore) {
+            // This happens on older paper servers, or plain Spigot servers
+        }
     }
 
     @Override
@@ -88,4 +107,28 @@ public boolean isOwnedByCurrentRegion(@NotNull Entity entity) {
     public void cancelTasks() {
         owningPlugin.getServer().getScheduler().cancelTasks(owningPlugin);
     }
+
+    @Override
+    public @NotNull CompletableFuture<Boolean> teleportAsync(@NotNull Entity entity, @NotNull Location location, PlayerTeleportEvent.@NotNull TeleportCause cause) {
+        // Check if the teleportAsync method is supported (Paper 1.13+)
+        if (teleportAsyncMethod != null) {
+            Object result = teleportAsyncMethod.invoke(entity, location, cause);
+            return (CompletableFuture<Boolean>) Objects.requireNonNull(result);
+        }
+
+        // Fallback to the synchronous teleport method, executed 1 tick later on the main thread
+        // to allow this method to be called asynchronously.
+        CompletableFuture<Boolean> future = new CompletableFuture<>();
+        entity(entity).run(task -> {
+            try {
+                entity.teleport(location);
+                future.complete(true);
+            } catch (Throwable ex) {
+                owningPlugin.getLogger().log(Level.SEVERE, "Failed to teleport entity", ex);
+                future.complete(false);
+            }
+        });
+
+        return future;
+    }
 }

src/main/java/com/cjcrafter/foliascheduler/ServerImplementation.java

@@ -5,9 +5,12 @@
 import org.bukkit.World;
 import org.bukkit.block.Block;
 import org.bukkit.entity.Entity;
+import org.bukkit.event.player.PlayerTeleportEvent;
 import org.bukkit.plugin.Plugin;
 import org.jetbrains.annotations.NotNull;
 
+import java.util.concurrent.CompletableFuture;
+
 public interface ServerImplementation {
 
     /**
@@ -139,4 +142,35 @@ public interface ServerImplementation {
      * @see <a href="https://github.com/CJCrafter/FoliaScheduler/issues/28">Issue #28</a>
      */
     void cancelTasks();
+
+    /**
+     * Teleports an entity to a location. If chunks need to be loaded, those chunks will be loaded
+     * asynchronously. Shortcut for {@link #teleportAsync(Entity, Location, PlayerTeleportEvent.TeleportCause)}.
+     *
+     * @param entity The entity to teleport
+     * @param location The location to teleport the entity to
+     * @return A future that completes when the entity is teleported, or the teleport fails
+     */
+    default @NotNull CompletableFuture<Boolean> teleportAsync(@NotNull Entity entity, @NotNull Location location) {
+        return teleportAsync(entity, location, PlayerTeleportEvent.TeleportCause.PLUGIN);
+    }
+
+    /**
+     * Teleports an entity to a location. If chunks need to be loaded, those chunks will be loaded
+     * asynchronously.
+     *
+     * <p>The returned {@link CompletableFuture future} will complete when the entity is teleported,
+     * or the teleport fails. If the teleport fails, the future will complete with a value of
+     * {@code false}.
+     *
+     * <p>Note that this method is only asynchronous on Paper servers, versions 1.13 and later. On
+     * other servers, this method will be delegated to a synchronous task that executes
+     * {@link Entity#teleport(Location)} in the main thread (which may lead to lag spikes).
+     *
+     * @param entity The entity to teleport
+     * @param location The location to teleport the entity to
+     * @param cause The cause of the teleport
+     * @return A future that completes when the entity is teleported, or the teleport fails
+     */
+    @NotNull CompletableFuture<Boolean> teleportAsync(@NotNull Entity entity, @NotNull Location location, @NotNull PlayerTeleportEvent.TeleportCause cause);
 }