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));
}
/// <summary>
/// 将三键对象插入到缓存域，如果缓存域已存在该对象，则替换。
/// </summary>
/// <param name="param1">要移除三键对象对应分组键参数一值。</param>
/// <param name="param2">要移除三键对象对应分组键参数二值。</param>
/// <param name="entity">要插入缓存域的三键对象。</param>
public void SetItemToCache(TParam1 param1, TParam2 param2, TEntity entity)
{
if (entity == null)
{
throw new ArgumentNullException("entity");
}
Cache.Set(option.GetCacheKey(param1, param2, option.EntityKeySelector(entity)), entity);
}