rafactor subscriber handler.

src/DotNetCore.CAP/Internal/ISubscriberExecutor.Default.cs

+using System;
+using System.Threading.Tasks;
+using DotNetCore.CAP.Abstractions;
+using DotNetCore.CAP.Models;
+using Microsoft.Extensions.Logging;
+
+namespace DotNetCore.CAP.Internal
+{
+    public class DefaultSubscriberExecutor : ISubscriberExecutor
+    {
+        private readonly IConsumerInvokerFactory _consumerInvokerFactory;
+        private readonly ILogger<DefaultSubscriberExecutor> _logger;
+        private readonly MethodMatcherCache _selector;
+
+        public DefaultSubscriberExecutor(MethodMatcherCache selector,
+            IConsumerInvokerFactory consumerInvokerFactory,
+            ILogger<DefaultSubscriberExecutor> logger)
+        {
+            _selector = selector;
+            _consumerInvokerFactory = consumerInvokerFactory;
+            _logger = logger;
+        }
+
+
+        public async Task<OperateResult> ExecuteAsync(CapReceivedMessage receivedMessage)
+        {
+            try
+            {
+                var executeDescriptorGroup = _selector.GetTopicExector(receivedMessage.Name);
+
+                if (!executeDescriptorGroup.ContainsKey(receivedMessage.Group))
+                {
+                    var error = $"Topic:{receivedMessage.Name}, can not be found subscriber method.";
+                    throw new SubscriberNotFoundException(error);
+                }
+
+                // If there are multiple consumers in the same group, we will take the first
+                var executeDescriptor = executeDescriptorGroup[receivedMessage.Group][0];
+                var consumerContext = new ConsumerContext(executeDescriptor, receivedMessage.ToMessageContext());
+
+                await _consumerInvokerFactory.CreateInvoker(consumerContext).InvokeAsync();
+
+                return OperateResult.Success;
+            }
+            catch (Exception ex)
+            {
+                _logger.ConsumerMethodExecutingFailed($"Group:{receivedMessage.Group}, Topic:{receivedMessage.Name}",
+                    ex);
+
+                return OperateResult.Failed(ex);
+            }
+        }
+    }
+}
\ No newline at end of file

src/DotNetCore.CAP/Internal/ISubscriberExecutor.cs

+using System.Threading.Tasks;
+using DotNetCore.CAP.Models;
+
+namespace DotNetCore.CAP.Internal
+{
+    public interface ISubscriberExecutor
+    {
+        Task<OperateResult> ExecuteAsync(CapReceivedMessage receivedMessage);
+    }
+}