filter a recycler view data

ItemAdapter.java

package com.octopus.searchviewwithrecycler;

import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Filter;
import android.widget.Filterable;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

import java.util.ArrayList;
import java.util.List;

public class ItemAdapter extends RecyclerView.Adapter<ItemAdapter.ViewHolder> implements Filterable {
    private List<String> list;
    private List<String> filteredItem;

    public ItemAdapter(List<String> list) {
        this.list = list;
        this.filteredItem = list;
    }

    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item_name,
                parent, false);
        return new ViewHolder(itemView);
    }

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        String itemName = filteredItem.get(position);
        holder.itemName.setText(itemName);

    }

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

    private Filter filter = new Filter() {
        @Override
        protected FilterResults performFiltering(CharSequence constraint) {
            String key = constraint.toString();
            if (key.isEmpty()) {
                filteredItem = list;
            } else {
                List<String> filteredList = new ArrayList<>();
                for (String s : list) {
                    if (s.toLowerCase().contains(key.toLowerCase())) {
                        filteredList.add(s);
                    }
                }

                filteredItem = filteredList;
            }

            FilterResults results = new FilterResults();
            results.values = filteredItem;
            return results;

        }

        @Override
        protected void publishResults(CharSequence constraint, FilterResults results) {
            filteredItem = (List<String>) results.values;
            notifyDataSetChanged();

        }
    };

    @Override
    public Filter getFilter() {
        return filter;
    }


    public static class ViewHolder extends RecyclerView.ViewHolder {
        private TextView itemName;

        public ViewHolder(@NonNull View view) {
            super(view);
            itemName = view.findViewById(R.id.item_name);
        }
    }
}