Dirty AutoRegistry

AutoRegistry.java

/**
 * <h2>USAGE EXAMPLE</h2>
 *
 * <p>In your ModInitializer:
 * <pre>{@code
 * AutoRegistry.create(MODID)
 *      .run(Registries.BLOCK, MyBlocks.class)
 *      .run(Registries.ITEM, MyItems.class);
 * }</pre>
 *
 * <p>In your MyBlocks/Items/etc classes:
 * <pre>{@code
 * public class MyBlocks {
 *     public static final @RegistryObject MagicCauldronBlock MAGIC_CAULDRON = new MagicCauldronBlock();
 * }
 * }</pre>
 */
public class AutoRegistry {
    private final String modid;
    private final Logger logger;

    protected AutoRegistry(String modid, Logger logger) {
        this.modid = modid;
        this.logger = logger;
    }

    public static AutoRegistry create(String modid, Logger logger) {
        return new AutoRegistry(modid, logger);
    }

    /**
     * Registers all the objects in the provided class into the provided registry by the following rules:
     * <ul>
     *     <li>Only the public static fields marked with @RegistryObject are scanned</li>
     *     <li>The ID is formed by lower-casing the field name</li>
     *     <li>Null fields are discarded with a warning message</li>
     * </ul>
     * @param <T> type parameter must match the type of the fields
     * @implNote help
     */
    public <T> AutoRegistry run(Registry<T> registry, Class<?> holderClass) {
        for (var field : holderClass.getDeclaredFields()) {
            var modifiers = field.getModifiers();
            var annotations = field.getAnnotationsByType(RegistryObject.class);
            if (!Modifier.isStatic(modifiers)
                    || !Modifier.isPublic(modifiers)
                    || annotations.length == 0) {
                continue;
            }

            try {
                var registryObject = field.get(holderClass);
                if (registryObject == null) {
                    logger.warn("Found a null @RegistryObject field, discarding: %s at %s".formatted(field.getName(), holderClass.getCanonicalName()));
                    continue;
                }

                Registry.register(registry, new Identifier(modid, field.getName().toLowerCase()), (T) registryObject);
            } catch (IllegalAccessException e) {
                throw new InaccessibleObjectException("Couldn't read a @RegistryObject field: %s at %s".formatted(field.getName(), holderClass.getCanonicalName()));
            } catch (ClassCastException e) {
                throw new IllegalArgumentException("A @RegistryObject field's type doesn't match the provided registry: %s at %s".formatted(field.getName(), holderClass.getCanonicalName()));
            }
        }
        return this;
    }
}