designPatternGuru/DesignPatternGuru/ChainOfResponsibility/COR/AbstractHandler.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ChainOfResponsibility.COR
{
    internal abstract class AbstractHandler : IHandler
    {
        private IHandler _nextHandler;

        public IHandler SetNext(IHandler handler)
        {
            _nextHandler = handler;
            return _nextHandler;
        }

        public virtual object Handle(object request)
        {
            if (_nextHandler == null)
                return null;

            return _nextHandler.Handle(request);
        }
    }
}