Line data    Source code

       1             : using System;
       2             : using System.Collections.Concurrent;
       3             : using System.Collections.Generic;
       4             : using System.Linq;
       5             : using System.Runtime.Caching;
       6             : using Cqrs.Domain;
       7             : using Cqrs.Events;
       8             : 
       9             : namespace Cqrs.Cache
      10             : {
      11             :         public class CacheRepository<TAuthenticationToken> : IRepository<TAuthenticationToken>
      12           0 :         {
      13             :                 private IRepository<TAuthenticationToken> Repository { get; set; }
      14             : 
      15             :                 private IEventStore<TAuthenticationToken> EventStore { get; set; }
      16             : 
      17             :                 private MemoryCache Cache { get; set; }
      18             : 
      19             :                 private Func<CacheItemPolicy> PolicyFactory { get; set; }
      20             : 
      21             :                 private static readonly ConcurrentDictionary<string, object> Locks = new ConcurrentDictionary<string, object>();
      22             : 
      23           0 :                 public CacheRepository(IRepository<TAuthenticationToken> repository, IEventStore<TAuthenticationToken> eventStore)
      24             :                 {
      25             :                         if(repository == null)
      26             :                                 throw new ArgumentNullException("repository");
      27             :                         if(eventStore == null)
      28             :                                 throw new ArgumentNullException("eventStore");
      29             : 
      30             :                         Repository = repository;
      31             :                         EventStore = eventStore;
      32             :                         Cache = MemoryCache.Default;
      33             :                         PolicyFactory = () => new CacheItemPolicy
      34             :                                 {
      35             :                                         SlidingExpiration = new TimeSpan(0,0,15,0),
      36             :                                         RemovedCallback = x =>
      37             :                                         {
      38             :                                                 object o;
      39             :                                                 Locks.TryRemove(x.CacheItem.Key, out o);
      40             :                                         }
      41             :                                 };
      42             :                 }
      43             : 
      44           0 :                 public void Save<TAggregateRoot>(TAggregateRoot aggregate, int? expectedVersion = null)
      45             :                         where TAggregateRoot : IAggregateRoot<TAuthenticationToken>
      46             :                 {
      47             :                         var idstring = aggregate.Id.ToString();
      48             :                         try
      49             :                         {
      50             :                                 lock (Locks.GetOrAdd(idstring, x => new object()))
      51             :                                 {
      52             :                                         if (aggregate.Id != Guid.Empty && !IsTracked(aggregate.Id))
      53             :                                                 Cache.Add(idstring, aggregate, PolicyFactory.Invoke());
      54             :                                         Repository.Save(aggregate, expectedVersion);
      55             :                                 }
      56             :                         }
      57             :                         catch (Exception)
      58             :                         {
      59             :                                 Cache.Remove(idstring);
      60             :                                 throw;
      61             :                         }
      62             :                 }
      63             : 
      64           0 :                 public TAggregateRoot Get<TAggregateRoot>(Guid aggregateId, IList<IEvent<TAuthenticationToken>> events = null)
      65             :                         where TAggregateRoot : IAggregateRoot<TAuthenticationToken>
      66             :                 {
      67             :                         string idstring = aggregateId.ToString();
      68             :                         try
      69             :                         {
      70             :                                 IList<IEvent<TAuthenticationToken>> theseEvents = null;
      71             :                                 lock (Locks.GetOrAdd(idstring, _ => new object()))
      72             :                                 {
      73             :                                         TAggregateRoot aggregate;
      74             :                                         if (IsTracked(aggregateId))
      75             :                                         {
      76             :                                                 aggregate = (TAggregateRoot)Cache.Get(idstring);
      77             :                                                 theseEvents = events ?? EventStore.Get<TAggregateRoot>(aggregateId, false, aggregate.Version).ToList();
      78             :                                                 if (theseEvents.Any() && theseEvents.First().Version != aggregate.Version + 1)
      79             :                                                 {
      80             :                                                         Cache.Remove(idstring);
      81             :                                                 }
      82             :                                                 else
      83             :                                                 {
      84             :                                                         aggregate.LoadFromHistory(theseEvents);
      85             :                                                         return aggregate;
      86             :                                                 }
      87             :                                         }
      88             : 
      89             :                                         aggregate = Repository.Get<TAggregateRoot>(aggregateId, theseEvents);
      90             :                                         Cache.Add(aggregateId.ToString(), aggregate, PolicyFactory.Invoke());
      91             :                                         return aggregate;
      92             :                                 }
      93             :                         }
      94             :                         catch (Exception)
      95             :                         {
      96             :                                 Cache.Remove(idstring);
      97             :                                 throw;
      98             :                         }
      99             :                 }
     100             : 
     101             :                 private bool IsTracked(Guid id)
     102             :                 {
     103             :                         return Cache.Contains(id.ToString());
     104             :                 }
     105             :         }
     106             : }