add getItemProperty

api/src/main/java/lol/pyr/znpcsplus/api/entity/PropertyHolder.java

@@ -43,6 +43,14 @@ public interface PropertyHolder {
      */
     void setItemProperty(EntityProperty<?> key, ItemStack value);
 
+    /**
+     * Weird fix which is sadly required in order to not decrease performance
+     * when using item properties, read https://github.com/Pyrbu/ZNPCsPlus/pull/129#issuecomment-1948777764
+     *
+     * @param key Unique key representing a property
+     */
+    ItemStack getItemProperty(EntityProperty<?> key);
+
     /**
      * Method used to get a set of all of the property keys that this holder has a value for
      *

plugin/src/main/java/lol/pyr/znpcsplus/entity/PacketEntity.java

@@ -107,6 +107,11 @@ public class PacketEntity implements PropertyHolder {
         properties.setItemProperty(key, value);
     }
 
+    @Override
+    public ItemStack getItemProperty(EntityProperty<?> key) {
+        return properties.getItemProperty(key);
+    }
+
     @Override
     public Set<EntityProperty<?>> getAppliedProperties() {
         return properties.getAppliedProperties();

plugin/src/main/java/lol/pyr/znpcsplus/hologram/HologramLine.java

@@ -1,6 +1,7 @@
 package lol.pyr.znpcsplus.hologram;
 
 import com.github.retrooper.packetevents.protocol.entity.type.EntityType;
+import io.github.retrooper.packetevents.util.SpigotConversionUtil;
 import lol.pyr.znpcsplus.api.entity.EntityProperty;
 import lol.pyr.znpcsplus.api.entity.PropertyHolder;
 import lol.pyr.znpcsplus.entity.PacketEntity;
@@ -76,6 +77,12 @@ public class HologramLine<M> implements PropertyHolder {
         throw new UnsupportedOperationException("Can't set properties on a hologram line");
     }
 
+    @SuppressWarnings("unchecked")
+    @Override
+    public ItemStack getItemProperty(EntityProperty<?> key) {
+        return SpigotConversionUtil.toBukkitItemStack(((EntityProperty<com.github.retrooper.packetevents.protocol.item.ItemStack>) key).getDefaultValue());
+    }
+
     @Override
     public Set<EntityProperty<?>> getAppliedProperties() {
         return properties;

plugin/src/main/java/lol/pyr/znpcsplus/npc/NpcImpl.java

@@ -164,6 +164,12 @@ public class NpcImpl extends Viewable implements Npc {
         setProperty((EntityPropertyImpl<com.github.retrooper.packetevents.protocol.item.ItemStack>) key, SpigotConversionUtil.fromBukkitItemStack(value));
     }
 
+    @SuppressWarnings("unchecked")
+    @Override
+    public ItemStack getItemProperty(EntityProperty<?> key) {
+        return SpigotConversionUtil.toBukkitItemStack(getProperty((EntityProperty<com.github.retrooper.packetevents.protocol.item.ItemStack>) key));
+    }
+
     public <T> void setProperty(EntityPropertyImpl<T> key, T value) {
         if (key == null) return;
         if (value == null || value.equals(key.getDefaultValue())) propertyMap.remove(key);