Use Consumers when spawning custom entities

When you want to spawn a custom entity, e.g. with a custom name or certain items equipped, you must use the method World#spawn(Location, Class<T extends Entity>, Consumer<T>) unless you give a shit about compatibility with other plugins. I’ll explain why.

The shitty way

Usually, you can easily spawn entities like this:

Pig myPig = location.getWorld().spawn(location, Pig.class);
// or alternatively:
Pig myPig = (Pig) location.getWorld().spawnEntity(location, EntityType.PIG);

That is fine, as long as you don’t want to change any data of that entity right away. For example, let’s assume that we want to give our pig a custom name, let’s say oliver193. You might be tempted to simply do it like this:

Pig myPig = location.getWorld().spawn(location, Pig.class);
myPig.setCustomName("oliver193");
myPig.setCustomNameVisible(true);

Never ever do that unless you don’t care about compatibility with other plugins. Let’s just imagine for a second that we have another plugin that simply prints a message to console whenever a named entity spawns:

@EventHandler(priority = EventPriority.MONITOR, ignoreCancelled = true)
public void onNamedEntitySpawn(CreatureSpawnEvent event) {
    String customName = event.getEntity().getCustomName();
    if(customName == null) return;
    getLogger().info("A custom entity named \"" + customName + "\" spawned at " + event.getEntity().getLocation());
}

Obviously, this will not work, since we spawned the Pig before giving it a custom name. That sucks.

The proper way

However, we can easily achieve the same thing in a proper way by actually setting the data before adding the entity to the world, by providing a Consumer<Pig> to the spawn method:

Pig myPig = location.getWorld().spawn(location, Pig.class, (pig) -> {
    pig.setCustomName("oliver193");
    pig.setCustomNameVisible(true);
});