protected TEntity GetItem <TEntity, TKey>(ICache cache, TKey key, CacheDomainOption <TEntity, TKey> option)
{
var cacheKey = option.GetCacheKey(key);
var cacheItem = cache.Get <TEntity>(cacheKey);
if (cacheItem == null)
{
//根据缓存名获取锁对象
object sync = GetSyncObject(option.GetCacheFullName());
lock (sync)
{
//再次从缓存读取
cacheItem = cache.Get <TEntity>(cacheKey);
if (cacheItem == null)
{
//从原始数据读取
cacheItem = option.MissingItemHandler(key);
if (!AbstractCache.IsDefault(cacheItem))
{
OnSetCache(cache, cacheKey, cacheItem, option.SecondesToLive);
}
}
}
}
return(cacheItem);
}
private CacheDomain(CacheDomainOption <TEntity> option)
: base(option)
{
if (option.MissingItemHandler == null)
{
throw new ArgumentNullException("MissingItemHandler");
}
this.option = option;
}
internal AbstractCacheDomain(CacheDomainOption option)
{
cache = CacheManager.GetCacher(option.GetCacheFullName());
//使用缓存代理处理
if (option.ContextCacheEnabled && !(cache is AspnetCache))
{
cache = new CacheProxy(cache);
}
}
private CacheDomain(CacheDomainOption <TEntity, TParam1, TParam2, TKey> option)
: base(option)
{
if (option.EntityKeySelector == null)
{
throw new ArgumentNullException("EntityKeySelector");
}
if (option.MissingItemHandler == null && option.MissingItemsHandler == null)
{
throw new ArgumentNullException("MissingItemHandler 与 MissingItemsHandler 至少有一个不能为 Null.");
}
this.option = option;
}
protected IEnumerable <TEntity> GetItems <TEntity, TParam1, TParam2, TKey>(ICache cache, TParam1 param1, TParam2 param2, IEnumerable <TKey> keys, CacheDomainOption <TEntity, TParam1, TParam2, TKey> option)
{
//CacheKey 与属性键的映射（去重）
IDictionary <string, TKey> keyDic = keys.Distinct().ToDictionary(key => option.GetCacheKey(param1, param2, key));
//访问缓存并获取不在缓存中的 CacheKey
IEnumerable <string> missing;
var cacheItems = cache.GetBatch <TEntity>(keyDic.Keys, out missing).ToList();
if (missing.Count() > 0)
{
//根据缓存名获取锁对象
object sync = GetSyncObject(option.GetCacheFullName());
lock (sync)
{
//二次查找缓存
IEnumerable <string> secondMissing;
var secondCacheItems = cache.GetBatch <TEntity>(missing, out secondMissing).ToList();
cacheItems.AddRange(secondCacheItems);
//从数据源获取
if (secondMissing.Count() > 0)
{
IEnumerable <TEntity> dbItems = option.GetMissingItems(param1, param2, secondMissing.Select(key => keyDic[key]).ToArray());
//过滤掉 null 项，并加入缓存
OnSetCacheBatch(cache, dbItems.Where(item => !AbstractCache.IsDefault(item)), key => option.GetCacheKey(param1, param2, option.EntityKeySelector(key)), option.SecondesToLive);
cacheItems.AddRange(dbItems);
}
}
}
//按目标序列输出
return(cacheItems.OrderBy(entity => option.EntityKeySelector(entity), keys));
}