SPIGOT-6829: Add per-player world border API

By: Parker Hawke <hawkeboyz2@hotmail.com>

paper-api/src/main/java/org/bukkit/Bukkit.java

@@ -715,6 +715,18 @@ public final class Bukkit {
         return server.getWorld(uid);
     }
 
+    /**
+     * Create a new virtual {@link WorldBorder}.
+     *
+     * @return the created world border instance
+     *
+     * @see Player#setWorldBorder(WorldBorder)
+     */
+    @NotNull
+    public static WorldBorder createWorldBorder() {
+        return server.createWorldBorder();
+    }
+
     /**
      * Gets the map from the given item ID.
      *

paper-api/src/main/java/org/bukkit/Server.java

@@ -604,6 +604,19 @@ public interface Server extends PluginMessageRecipient {
     @Nullable
     public World getWorld(@NotNull UUID uid);
 
+    /**
+     * Create a new virtual {@link WorldBorder}.
+     * <p>
+     * Note that world borders created by the server will not respect any world
+     * scaling effects (i.e. coordinates are not divided by 8 in the nether).
+     *
+     * @return the created world border instance
+     *
+     * @see Player#setWorldBorder(WorldBorder)
+     */
+    @NotNull
+    public WorldBorder createWorldBorder();
+
     /**
      * Gets the map from the given item ID.
      *

paper-api/src/main/java/org/bukkit/WorldBorder.java

@@ -1,9 +1,19 @@
 package org.bukkit;
 
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 public interface WorldBorder {
 
+    /**
+     * Get the {@link World} in which the border resides.
+     *
+     * @return the associated world, or null if this world border is not associated
+     * with any specific world, such as those created via {@link Server#createWorldBorder()}
+     */
+    @Nullable
+    public World getWorld();
+
     /**
      * Resets the border to default values.
      */

paper-api/src/main/java/org/bukkit/entity/Player.java

@@ -10,9 +10,11 @@ import org.bukkit.Material;
 import org.bukkit.Note;
 import org.bukkit.OfflinePlayer;
 import org.bukkit.Particle;
+import org.bukkit.Server;
 import org.bukkit.Sound;
 import org.bukkit.SoundCategory;
 import org.bukkit.WeatherType;
+import org.bukkit.WorldBorder;
 import org.bukkit.advancement.Advancement;
 import org.bukkit.advancement.AdvancementProgress;
 import org.bukkit.block.Block;
@@ -1153,6 +1155,28 @@ public interface Player extends HumanEntity, Conversable, OfflinePlayer, PluginM
      */
     public void setScoreboard(@NotNull Scoreboard scoreboard) throws IllegalArgumentException, IllegalStateException;
 
+    /**
+     * Gets the {@link WorldBorder} visible to this Player, or null if viewing
+     * the world's world border.
+     *
+     * @return the player's world border
+     */
+    @Nullable
+    public WorldBorder getWorldBorder();
+
+    /**
+     * Sets the {@link WorldBorder} visible to this Player.
+     *
+     * @param border the border to set, or null to set to the world border of
+     * the player's current world
+     *
+     * @throws UnsupportedOperationException if setting the border to that of
+     * a world in which the player is not currently present.
+     *
+     * @see Server#createWorldBorder()
+     */
+    public void setWorldBorder(@Nullable WorldBorder border);
+
     /**
      * Gets if the client is displayed a 'scaled' health, that is, health on a
      * scale from 0-{@link #getHealthScale()}.