在ABP框架中存在一个缓存机制，使用ICache的继承类来存储最终需要缓存的数据，可以吧ICache看成一个字典对象，使用Key作为真实数据的具有唯一性的表示。使用上与字典对象完全相同，Get方法传递Key，还有数据工厂作为参数就能返回最终的值，Set方法用于存储。包含一个TimeSpan属性用于指定最长不使用数据的过期时间。
/// <summary> /// Defines a cache that can be store and get items by keys. /// </summary> public interface ICache : IDisposable { /// <summary> /// Unique name of the cache. /// </summary> string Name { get; } /// <summary> /// Default sliding expire time of cache items. /// Default value: 60 minutes. Can be changed by configuration. /// </summary> TimeSpan DefaultSlidingExpireTime { get; set; } /// <summary> /// Gets an item from the cache. /// </summary> /// <param name="key">Key</param> /// <param name="factory">Factory method to create cache item if not exists</param> /// <returns>Cached item</returns> object Get(string key, Func<string, object> factory); /// <summary> /// Gets an item from the cache. /// </summary> /// <param name="key">Key</param> /// <param name="factory">Factory method to create cache item if not exists</param> /// <returns>Cached item</returns> Task<object> GetAsync(string key, Func<string, Task<object>> factory); /// <summary> /// Gets an item from the cache or null if not found. /// </summary> /// <param name="key">Key</param> /// <returns>Cached item or null if not found</returns> object GetOrDefault(string key); /// <summary> /// Gets an item from the cache or null if not found. /// </summary> /// <param name="key">Key</param> /// <returns>Cached item or null if not found</returns> Task<object> GetOrDefaultAsync(string key); /// <summary> /// Saves/Overrides an item in the cache by a key. /// </summary> /// <param name="key">Key</param> /// <param name="value">Value</param> /// <param name="slidingExpireTime">Sliding expire time</param> void Set(string key, object value, TimeSpan? slidingExpireTime = null); /// <summary> /// Saves/Overrides an item in the cache by a key. /// </summary> /// <param name="key">Key</param> /// <param name="value">Value</param> /// <param name="slidingExpireTime">Sliding expire time</param> Task SetAsync(string key, object value, TimeSpan? slidingExpireTime = null); /// <summary> /// Removes a cache item by it‘s key. /// </summary> /// <param name="key">Key</param> void Remove(string key); /// <summary> /// Removes a cache item by it‘s key (does nothing if given key does not exists in the cache). /// </summary> /// <param name="key">Key</param> Task RemoveAsync(string key); /// <summary> /// Clears all items in this cache. /// </summary> void Clear(); /// <summary> /// Clears all items in this cache. /// </summary> Task ClearAsync(); }
框架中提供了一个ICache的抽象实现类CacheBase，作为所有具体缓存方式的基类，实现了所有基础逻辑，最终的Cache对象只需继承CacheBase，并重写object GetOrDefault(string key)，void Set(string key, object value, TimeSpan? slidingExpireTime = null)，void Clear()等三个抽象方法就可以完成一个真实可用的缓存Cache（另外Dispose方法通常是需要重写）。同时CacheBase的所有其他公共方法也是可重写的。ABP中默认提供了一个以内存方式缓存数据的实现即AbpMemoryCache，只是简单实用微软的MemoryCache类作为内部缓存容器。
ICacheManager使用单例模式用于管理所有的ICache，其中包含一个传递Key返回ICache的GetCache方法，还有一个返回所有ICache的GetAllCaches方法，在调用GetCache传递Key的时候如果不存在就会创建一个新的保存起来，对于ICacheManager框架中已经存在一个名为CacheManagerBase的抽象实现了，其内部有一个线程安全的字典用于存放所有的ICache，用于需要继承CacheManagerBase实现自身的CacheManager，只需要实现抽象方法CreateCacheImplementation就行了，最简单的方式就是在方法内部返回一个AbpMemoryCache实例就行了
/// <summary> /// An upper level container for <see cref="ICache"/> objects. /// A cache manager should work as Singleton and track and manage <see cref="ICache"/> objects. /// </summary> public interface ICacheManager : IDisposable { /// <summary> /// Gets all caches. /// </summary> /// <returns>List of caches</returns> IReadOnlyList<ICache> GetAllCaches(); /// <summary> /// Gets (or creates) a cache. /// </summary> /// <param name="name">Unique name of the cache</param> /// <returns>The cache reference</returns> ICache GetCache(string name); }
缓存机制中存在一个ICachingConfiguration的配置类，用户可以在自定义的模块中添加ICache的初始化处理逻辑，通常是一个Action<ICache>的委托，添加到配置类的Configurators属性中，每次被创建一个新的ICache对象的时候都会遍历Configurators属性中名称与新建ICache相同，或者无名称的全局性Action<ICache>，用来初始化ICache。
/// <summary> /// Used to configure caching system. /// </summary> public interface ICachingConfiguration { /// <summary> /// List of all registered configurators. /// </summary> IReadOnlyList<ICacheConfigurator> Configurators { get; } /// <summary> /// Used to configure all caches. /// </summary> /// <param name="initAction"> /// An action to configure caches /// This action is called for each cache just after created. /// </param> void ConfigureAll(Action<ICache> initAction); /// <summary> /// Used to configure a specific cache. /// </summary> /// <param name="cacheName">Cache name</param> /// <param name="initAction"> /// An action to configure the cache. /// This action is called just after the cache is created. /// </param> void Configure(string cacheName, Action<ICache> initAction); }
/// <summary> /// A registered cache configurator. /// </summary> public interface ICacheConfigurator { /// <summary> /// Name of the cache. /// It will be null if this configurator configures all caches. /// </summary> string CacheName { get; } /// <summary> /// Configuration action. Called just after the cache is created. /// </summary> Action<ICache> InitAction { get; } }
另外因为所有数据都是以字符串为Key，值为Object的方式存储的，所以对于一些依赖强类型的使用不太方便，作者也添加了ITypedCache<TKey,TValue>的方式，用于返回强类型的数据，虽然使用方便的，但是ICache所能缓存的对象也有了限制。
原文：http://www.cnblogs.com/Azula/p/5208179.html