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184 lines
6.0 KiB
C#

using System;
using System.Collections.Generic;
using System.Linq;
namespace Admin.Core.EventBus
{
/// <summary>
/// 基于内存
/// 事件总线订阅管理器
/// 单例模式
/// </summary>
public partial class InMemoryEventBusSubscriptionsManager : IEventBusSubscriptionsManager
{
private readonly Dictionary<string, List<SubscriptionInfo>> _handlers;
private readonly List<Type> _eventTypes;
public event EventHandler<string> OnEventRemoved;
public InMemoryEventBusSubscriptionsManager()
{
_handlers = new Dictionary<string, List<SubscriptionInfo>>();
_eventTypes = new List<Type>();
}
public bool IsEmpty => !_handlers.Keys.Any();
public void Clear() => _handlers.Clear();
/// <summary>
/// 添加动态订阅
/// </summary>
/// <typeparam name="TH">约束:动态事件处理器接口</typeparam>
/// <param name="eventName"></param>
public void AddDynamicSubscription<TH>(string eventName)
where TH : IDynamicIntegrationEventHandler
{
DoAddSubscription(typeof(TH), eventName, isDynamic: true);
}
/// <summary>
/// 添加订阅
/// </summary>
/// <typeparam name="T">约束:事件</typeparam>
/// <typeparam name="TH">约束:事件处理器接口<事件></typeparam>
public void AddSubscription<T, TH>()
where T : IntegrationEvent
where TH : IIntegrationEventHandler<T>
{
var eventName = GetEventKey<T>();
DoAddSubscription(typeof(TH), eventName, isDynamic: false);
if (!_eventTypes.Contains(typeof(T)))
{
_eventTypes.Add(typeof(T));
}
}
private void DoAddSubscription(Type handlerType, string eventName, bool isDynamic)
{
if (!HasSubscriptionsForEvent(eventName))
{
_handlers.Add(eventName, new List<SubscriptionInfo>());
}
if (_handlers[eventName].Any(s => s.HandlerType == handlerType))
{
throw new ArgumentException(
$"Handler Type {handlerType.Name} already registered for '{eventName}'", nameof(handlerType));
}
if (isDynamic)
{
_handlers[eventName].Add(SubscriptionInfo.Dynamic(handlerType));
}
else
{
_handlers[eventName].Add(SubscriptionInfo.Typed(handlerType));
}
}
/// <summary>
/// 移除动态订阅
/// </summary>
/// <typeparam name="TH"></typeparam>
/// <param name="eventName"></param>
public void RemoveDynamicSubscription<TH>(string eventName)
where TH : IDynamicIntegrationEventHandler
{
var handlerToRemove = FindDynamicSubscriptionToRemove<TH>(eventName);
DoRemoveHandler(eventName, handlerToRemove);
}
public void RemoveSubscription<T, TH>()
where TH : IIntegrationEventHandler<T>
where T : IntegrationEvent
{
var handlerToRemove = FindSubscriptionToRemove<T, TH>();
var eventName = GetEventKey<T>();
DoRemoveHandler(eventName, handlerToRemove);
}
private void DoRemoveHandler(string eventName, SubscriptionInfo subsToRemove)
{
if (subsToRemove != null)
{
_handlers[eventName].Remove(subsToRemove);
if (!_handlers[eventName].Any())
{
_handlers.Remove(eventName);
var eventType = _eventTypes.SingleOrDefault(e => e.Name == eventName);
if (eventType != null)
{
_eventTypes.Remove(eventType);
}
RaiseOnEventRemoved(eventName);
}
}
}
public IEnumerable<SubscriptionInfo> GetHandlersForEvent<T>() where T : IntegrationEvent
{
var key = GetEventKey<T>();
return GetHandlersForEvent(key);
}
public IEnumerable<SubscriptionInfo> GetHandlersForEvent(string eventName) => _handlers[eventName];
private void RaiseOnEventRemoved(string eventName)
{
var handler = OnEventRemoved;
handler?.Invoke(this, eventName);
}
private SubscriptionInfo FindDynamicSubscriptionToRemove<TH>(string eventName)
where TH : IDynamicIntegrationEventHandler
{
return DoFindSubscriptionToRemove(eventName, typeof(TH));
}
/// <summary>
/// 查询订阅并移除
/// </summary>
/// <typeparam name="T"></typeparam>
/// <typeparam name="TH"></typeparam>
/// <returns></returns>
private SubscriptionInfo FindSubscriptionToRemove<T, TH>()
where T : IntegrationEvent
where TH : IIntegrationEventHandler<T>
{
var eventName = GetEventKey<T>();
return DoFindSubscriptionToRemove(eventName, typeof(TH));
}
private SubscriptionInfo DoFindSubscriptionToRemove(string eventName, Type handlerType)
{
if (!HasSubscriptionsForEvent(eventName))
{
return null;
}
return _handlers[eventName].SingleOrDefault(s => s.HandlerType == handlerType);
}
public bool HasSubscriptionsForEvent<T>() where T : IntegrationEvent
{
var key = GetEventKey<T>();
return HasSubscriptionsForEvent(key);
}
public bool HasSubscriptionsForEvent(string eventName) => _handlers.ContainsKey(eventName);
public Type GetEventTypeByName(string eventName) => _eventTypes.SingleOrDefault(t => t.Name == eventName);
public string GetEventKey<T>()
{
return typeof(T).Name;
}
}
}