Actions & conditions

Actions and conditions are smaller than power types and follow the same recipe: a class with a codec and one method, registered under an id. Once registered, they’re available in every power’s JSON — yours and everyone else’s.

Actions#

An action implements ActionType<Ctx, Cfg>. Ctx is the context it acts on; Cfg is its parsed config. The simplest actions need no config at all — use EmptyCfg:

public final class ExtinguishAction implements ActionType<EntityCtx, EmptyCfg> {

    @Override
    public MapCodec<EmptyCfg> codec() {
        return MapCodec.unit(EmptyCfg.INSTANCE);
    }

    @Override
    public void run(EmptyCfg cfg, EntityCtx ctx) {
        ctx.raw().clearFire();
    }
}

A configured action reads fields from its codec:

public record Cfg(int amount) {}

private static final MapCodec<Cfg> CODEC = RecordCodecBuilder.mapCodec(i -> i.group(
    Codec.INT.optionalFieldOf("amount", 1).forGetter(Cfg::amount)
).apply(i, Cfg::new));

@Override public void run(Cfg cfg, EntityCtx ctx) {
    ctx.living().heal(cfg.amount());
}

Contexts pick the flavour#

The Ctx type is what makes an action an entity action versus a bi-entity action:

Context	Flavour	run receives
EntityCtx	entity	one entity
BiEntityCtx	bi-entity	actor + target
BlockCtx	block	a position in a level
ItemCtx	item	an item stack

ctx.raw() gives the raw Entity (works for any entity — projectiles, items); ctx.living() gives the LivingEntity view when you need it. Prefer raw() unless you specifically need living-entity behaviour.

Registering#

Register into the matching action registry:

ActionTypes.ENTITY.register(MyMod.id("extinguish"), new ExtinguishAction());
ActionTypes.BIENTITY.register(MyMod.id("yank"), new YankAction());

Conditions#

Conditions are the same, but test returns a boolean instead of run doing work:

public final class OnFireCondition implements ConditionType<EntityCtx, EmptyCfg> {

    @Override public MapCodec<EmptyCfg> codec() {
        return MapCodec.unit(EmptyCfg.INSTANCE);
    }

    @Override public boolean test(EmptyCfg cfg, EntityCtx ctx) {
        return ctx.raw().isOnFire();
    }
}

Register into the matching condition registry:

ConditionTypes.ENTITY.register(MyMod.id("on_fire"), new OnFireCondition());

Apoli adds the universal inverted field for you at the wrapper level — you never implement inversion yourself. Return the plain, un-inverted answer.

Performance#

test and run are called wherever the containing power fires — potentially per tick, per hit, or per entity in a selector. Keep them allocation-free and O(1). Read the performance rules before shipping anything that runs in a loop.