Dispenser Behaviors

Add dispenser behaviors that don't overwrite everyone else's.

Vanilla's dispenser registry is one behavior per item, last registration wins. DispenserHelper wraps whatever is already registered instead, so several mods can add behavior to the same item and each falls through to the next when it doesn't apply. It also runs on datapack reload, so you can use tags.

Getting Started

public static void init() {
    RegHelper.addDynamicDispenserBehaviorRegistration(MyMod::registerDispenserBehaviors);
}

// runs on datapack reload, so tags are available here
public static void registerDispenserBehaviors(DispenserHelper.Event event) {
    event.registerPlaceBlock(Items.EMERALD_BLOCK);
    event.register(new SpawnDragonBehavior(Items.DRAGON_EGG));
}

public static class SpawnDragonBehavior extends DispenserHelper.AdditionalDispenserBehavior {

    protected SpawnDragonBehavior(Item item) {
        super(item);
    }

    @Override
    protected InteractionResultHolder<ItemStack> customBehavior(BlockSource source, ItemStack stack) {
        BlockPos front = source.pos().relative(source.state().getValue(DispenserBlock.FACING));
        if (source.level().getBlockState(front).isAir()) {
            // ... do the thing
            return InteractionResultHolder.success(stack);
        }
        // pass falls back to the previously registered behavior
        return InteractionResultHolder.pass(stack);
    }
}