Registry Conditions and Transformers

Registry conditions and transformers can filter and modify elements before they are passed to the LibX registration system.

Registry Conditions

Registry Conditions implement the RegistryCondition interface. They have a method called shouldRegister that is called with each object that is about to be registered. Only if all conditions return true for an object, it can be registered. To add a registry condition, use RegistrationBuilder#condition in your initRegistration method.

The following condition would exclude all Items from registration:

public class ExcludeItems implements RegistryCondition {

    public boolean shouldRegister(RegistrationContext ctx, Object value) {
        return ctx.registry().isEmpty() || Registries.ITEM != ctx.registry().get();
    }
}

Registry Transformers

Registry Transformers implement the RegistryTransformer interface. They have a method called transform that is called with each object that is about to be registered and passed the registry conditions. That method gets an EntryCollector as argument, which allows to register additional objects together with the original one. To add a registry transformer, use RegistrationBuilder#transformer in your initRegistration method.

The following transformer would register a BlockItem with every registered block:

public class BlockItems implements RegistryTransformer {

    public void transform(RegistrationContext ctx, Object value, Registerable.EntryCollector builder) {
        if (value instanceof Block block) {
            builder.register(Registries.ITEM, new BlockItem(block, new Item.Properties()));
        }
    }
}