#1378: Add methods to convert between an entity and a SNBT string

By: Jishuna <joshl5324@gmail.com>

paper-server/src/main/java/org/bukkit/craftbukkit/CraftServer.java

@@ -157,6 +157,7 @@ import org.bukkit.craftbukkit.boss.CraftKeyedBossbar;
 import org.bukkit.craftbukkit.command.BukkitCommandWrapper;
 import org.bukkit.craftbukkit.command.CraftCommandMap;
 import org.bukkit.craftbukkit.command.VanillaCommandWrapper;
+import org.bukkit.craftbukkit.entity.CraftEntityFactory;
 import org.bukkit.craftbukkit.entity.CraftPlayer;
 import org.bukkit.craftbukkit.event.CraftEventFactory;
 import org.bukkit.craftbukkit.generator.CraftWorldInfo;
@@ -305,6 +306,7 @@ public final class CraftServer implements Server {
         ConfigurationSerialization.registerClass(CraftOfflinePlayer.class);
         ConfigurationSerialization.registerClass(CraftPlayerProfile.class);
         CraftItemFactory.instance();
+        CraftEntityFactory.instance();
     }
 
     public CraftServer(DedicatedServer console, PlayerList playerList) {
@@ -2179,6 +2181,11 @@ public final class CraftServer implements Server {
         return CraftItemFactory.instance();
     }
 
+    @Override
+    public CraftEntityFactory getEntityFactory() {
+        return CraftEntityFactory.instance();
+    }
+
     @Override
     public CraftScoreboardManager getScoreboardManager() {
         return scoreboardManager;

paper-server/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java

@@ -780,6 +780,16 @@ public abstract class CraftEntity implements org.bukkit.entity.Entity {
         return getHandle().inWorld;
     }
 
+    @Override
+    public String getAsString() {
+        NBTTagCompound tag = new NBTTagCompound();
+        if (!getHandle().saveAsPassenger(tag, false)) {
+            return null;
+        }
+
+        return tag.getAsString();
+    }
+
     @Override
     public EntitySnapshot createSnapshot() {
         return CraftEntitySnapshot.create(this);

paper-server/src/main/java/org/bukkit/craftbukkit/entity/CraftEntityFactory.java

@@ -0,0 +1,44 @@
+package org.bukkit.craftbukkit.entity;
+
+import com.google.common.base.Preconditions;
+import com.mojang.brigadier.exceptions.CommandSyntaxException;
+import net.minecraft.nbt.MojangsonParser;
+import net.minecraft.nbt.NBTTagCompound;
+import net.minecraft.world.entity.EntityTypes;
+import org.bukkit.entity.EntityFactory;
+import org.bukkit.entity.EntitySnapshot;
+
+public class CraftEntityFactory implements EntityFactory {
+
+    private static final CraftEntityFactory instance;
+
+    static {
+        instance = new CraftEntityFactory();
+    }
+
+    private CraftEntityFactory() {
+    }
+
+    @Override
+    public EntitySnapshot createEntitySnapshot(String input) {
+        Preconditions.checkArgument(input != null, "Input string cannot be null");
+
+        NBTTagCompound tag;
+        try {
+            tag = MojangsonParser.parseTag(input);
+        } catch (CommandSyntaxException e) {
+            throw new IllegalArgumentException("Could not parse Entity: " + input, e);
+        }
+
+        EntityTypes<?> type = EntityTypes.by(tag).orElse(null);
+        if (type == null) {
+            throw new IllegalArgumentException("Could not parse Entity: " + input);
+        }
+
+        return CraftEntitySnapshot.create(tag, CraftEntityType.minecraftToBukkit(type));
+    }
+
+    public static CraftEntityFactory instance() {
+        return instance;
+    }
+}

paper-server/src/main/java/org/bukkit/craftbukkit/entity/CraftEntitySnapshot.java

@@ -42,6 +42,11 @@ public class CraftEntitySnapshot implements EntitySnapshot {
         return location.getWorld().addEntity(internal.getBukkitEntity());
     }
 
+    @Override
+    public String getAsString() {
+        return data.getAsString();
+    }
+
     private net.minecraft.world.entity.Entity createInternal(World world) {
         net.minecraft.world.level.World nms = ((CraftWorld) world).getHandle();
         net.minecraft.world.entity.Entity internal = EntityTypes.loadEntityRecursive(data, nms, Function.identity());