SPIGOT-4834: API for Villager levels and experience

src/main/java/org/bukkit/craftbukkit/entity/CraftVillager.java

@@ -1,5 +1,6 @@
 package org.bukkit.craftbukkit.entity;
 
+import com.google.common.base.Preconditions;
 import java.util.Locale;
 import net.minecraft.server.EntityVillager;
 import net.minecraft.server.IRegistry;
@@ -51,4 +52,28 @@ public class CraftVillager extends CraftAbstractVillager implements Villager {
         Validate.notNull(type);
         getHandle().setVillagerData(getHandle().getVillagerData().withType(IRegistry.VILLAGER_TYPE.get(CraftNamespacedKey.toMinecraft(type.getKey()))));
     }
+
+    @Override
+    public int getVillagerLevel() {
+        return getHandle().getVillagerData().getLevel();
+    }
+
+    @Override
+    public void setVillagerLevel(int level) {
+        Preconditions.checkArgument(0 <= level && level <= 5, "level must be between [0, 5]");
+
+        getHandle().setVillagerData(getHandle().getVillagerData().withLevel(level));
+    }
+
+    @Override
+    public int getVillagerExperience() {
+        return getHandle().dV();
+    }
+
+    @Override
+    public void setVillagerExperience(int experience) {
+        Preconditions.checkArgument(experience >= 0, "Experience must be positive");
+
+        getHandle().t(experience);
+    }
 }