MultiTypeAdapter for RecyclerView

MultiTypeAdapter.java

public class MultiTypeAdapter extends RecyclerView.Adapter {

    private final List<ViewHolderBuilder> builders;
    private final List<Item> items;

    MultiTypeAdapter(List<Item> items, List<ViewHolderBuilder> builders) {
        this.items = items;
        this.builders = builders;
    }

    @NonNull
    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        LayoutInflater inflater = LayoutInflater.from(parent.getContext());
        return builders.get(viewType).createViewHolder(inflater, parent);
    }

    @Override
    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
        Item item = items.get(position);
        for (int i = 0; i < builders.size(); i++) {
            ViewHolderBuilder builder = builders.get(i);
            Class itemClass = builder.getItemClass();
            if (itemClass.isInstance(item)) {
                //noinspection unchecked
                builder.bindViewHolder(holder, item);
                return;
            }
        }
        throw new IllegalStateException("holder for type not found: " + item);
    }

    @Override
    public int getItemCount() {
        return items.size();
    }

    @Override
    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position, @NonNull List payloads) {
        if (payloads.isEmpty()) {
            onBindViewHolder(holder, position);
        } else {
            Item item = items.get(position);
            for (int i = 0; i < builders.size(); i++) {
                ViewHolderBuilder builder = builders.get(i);
                Class itemClass = builder.getItemClass();
                if (itemClass.isInstance(item)) {
                    for (Object payload: payloads) {
                        //noinspection unchecked
                        builder.updateViewHolder(holder, item, payload);
                    }
                    return;
                }
            }
            throw new IllegalStateException("holder for type not found: " + item);
        }
    }

    @Override
    public int getItemViewType(int position) {
        Item item = items.get(position);
        for (int i = 0; i < builders.size(); i++) {
            ViewHolderBuilder builder = builders.get(i);
            Class itemClass = builder.getItemClass();
            if (itemClass.isInstance(item)) {
                return i;
            }
        }
        throw new IllegalStateException("holder for type not found: " + item);
    }

    public static class Builder {
        private final List<ViewHolderBuilder> builders = new ArrayList<>();
        private final List<Item> items;

        public Builder(List<Item> items) {
            this.items = items;
        }

        public <T extends RecyclerView.ViewHolder, E> Builder with(
                @Nonnull Class<E> itemClass,
                @Nonnull HolderCreator<T> holderCreator,
                @Nonnull HolderBinder<T, E> holderBinder,
                @Nullable HolderUpdater<T, E> holderUpdater) {
            builders.add(new ViewHolderBuilder<>(itemClass, holderCreator, holderBinder, holderUpdater));
            return this;
        }

        public <T extends RecyclerView.ViewHolder, E> Builder with(
                @Nonnull Class<E> itemClass,
                @Nonnull HolderCreator<T> holderCreator,
                @Nonnull HolderBinder<T, E> holderBinder) {
            return with(itemClass, holderCreator, holderBinder, null);
        }

        public MultiTypeAdapter build() {
            return new MultiTypeAdapter(items, builders);
        }
    }

    private static class ViewHolderBuilder<T extends RecyclerView.ViewHolder, E> {
        private @Nonnull Class<E> itemClass;
        private @Nonnull HolderCreator<T> holderCreator;
        private @Nonnull HolderBinder<T, E> holderBinder;
        private @Nullable HolderUpdater<T, E> holderUpdater;

        ViewHolderBuilder(@Nonnull Class<E> itemClass,
                          @Nonnull HolderCreator<T> holderCreator,
                          @Nonnull HolderBinder<T, E> holderBinder,
                          @Nullable HolderUpdater<T, E> holderUpdater) {
            this.itemClass = itemClass;
            this.holderCreator = holderCreator;
            this.holderBinder = holderBinder;
            this.holderUpdater = holderUpdater;
        }

        @Nonnull Class<E> getItemClass() {
            return itemClass;
        }

        @Nonnull  T createViewHolder(@NonNull LayoutInflater inflater, @NonNull ViewGroup parent) {
            return holderCreator.createViewHolder(inflater, parent);
        }

        void bindViewHolder(T holder, E item) {
            holderBinder.bindViewHolder(holder, item);
        }

        void updateViewHolder(T holder, E item, Object payload) {
            if (holderUpdater == null) {
                throw new NullPointerException("holder updater not implemented for holder: " + holder);
            }
            holderUpdater.updateViewHolder(holder, item, payload);
        }
    }

    public interface HolderCreator<T> {
        T createViewHolder(@NonNull LayoutInflater inflater, @NonNull ViewGroup parent);
    }

    public interface HolderBinder<T extends RecyclerView.ViewHolder, E> {
        void bindViewHolder(T holder, E item);
    }

    public interface HolderUpdater<T extends RecyclerView.ViewHolder, E> {
        void updateViewHolder(T holder, E item, Object payload);
    }
}