public override bool TryGet <T>(string key, out T entry)
{
Object cacheEntry;
Boolean exist = TryGetObject(key, out cacheEntry);
if (!exist)
{
//不存在
entry = default(T);
return(false);
}
if (cacheEntry == null)
{
//存在但为 null
entry = (T)((Object)null);
return(true);
}
if (cacheEntry is T)
{
//存在，直接返回
entry = (T)cacheEntry;
return(true);
}
//check json type
entry = NewtonsoftJsonUtil.EnsureObjectType <T>(cacheEntry);
return(true);
//if (!(cacheEntry is ExpirationWraper<T>)) {
// //类型不为 T 也不为 ExpirationWraper<T>，抛出异常
// throw new InvalidOperationException(String.Format("缓存项`[{0}]`类型错误, {1} or {2} ?",
// key, cacheEntry.GetType().FullName, typeof(T).FullName));
//}
//var cacheWraper = (ExpirationWraper<T>)cacheEntry;
////表示滑动过期缓存项
//if (cacheWraper.SlidingExpiration == Cache.NoSlidingExpiration) {
// //绝对时间过期，返回
// entry = cacheWraper.Value;
// return true;
//}
//var diffSpan = DateTime.Now.Subtract(cacheWraper.SettingTime);
////当前时间-设置时间>滑动时间, 已经过期
//if (diffSpan > cacheWraper.SlidingExpiration) {
// Expire(key);
// entry = default(T);
// return false;
//}
////当前时间-设置时间> 滑动时间/2, 更新缓存
//if (diffSpan.Add(diffSpan) > cacheWraper.SlidingExpiration) {
// entry = cacheWraper.Value;
// Overwrite(key, cacheWraper.Value, cacheWraper.SlidingExpiration);
//}
//entry = cacheWraper.Value;
//return true;
}
public override bool TryGet <T>(string key, out T entry)
{
Object cacheEntry;
Boolean exist = TryGetObject(key, out cacheEntry);
if (!exist)
{
//不存在
entry = default(T);
return(false);
}
if (cacheEntry == null)
{
//存在但为 null
entry = (T)((Object)null);
return(true);
}
if (cacheEntry is T)
{
//存在，直接返回
entry = (T)cacheEntry;
return(true);
}
//使用与不使用 NewtonsoftJsonTranscoder 的情况下都支持
SlidingCacheWrapper <T> slidingCache;
if (SlidingCacheWrapper <T> .IsSlidingCache(cacheEntry, out slidingCache))
{
//尝试以 SlidingCacheWrapper<T> 处理
var diffSpan = DateTime.Now.Subtract(slidingCache.SettingTime);
//当前时间-设置时间>滑动时间, 已经过期
if (diffSpan > slidingCache.SlidingExpiration)
{
Expire(key);
entry = default(T);
return(false);
}
//当前时间-设置时间> 滑动时间/2, 更新缓存
if (diffSpan.Add(diffSpan) > slidingCache.SlidingExpiration)
{
Overwrite(key, slidingCache.Value, slidingCache.SlidingExpiration);
}
entry = slidingCache.Value;
}
else
{
//尝试以普通JSON处理
entry = NewtonsoftJsonUtil.EnsureObjectType <T>(cacheEntry);
}
return(true);
}