/// <summary>
/// 设置一个缓存项，若键已存在则将覆盖，add a new item
/// </summary>
/// <param name="key"></param>
/// <param name="value"></param>
/// <param name="ttl">缓存时间，零值永不过期,单位：秒 <para>ttl, zero is no expired, unit: seconds.</para></param>
public void Set(TKey key, TValue value, int ttl)
{
int endTick = 0;
if (ttl > 0)
{
endTick = Environment.TickCount + ttl;
}
LinkedListNode <LRUCacheItem <TKey, TValue> > node;
if (this.dictionary.TryGetValue(key, out node))
{
this.list.Remove(node);
this.list.AddLast(node);
node.Value.ItemValue = value;
node.Value.EndTick = endTick;
}
else
{
//capacity - 1 differ
if (this.dictionary.Count > this.capacity)
//if (cachedObjects.Count >= capacity)
{
this.RemoveLastUsed();
}
LRUCacheItem <TKey, TValue> cacheItem = new LRUCacheItem <TKey, TValue>(key, value, endTick);
node = new LinkedListNode <LRUCacheItem <TKey, TValue> >(cacheItem);
this.list.AddLast(node);
this.dictionary.Add(key, node);
}
}
/// <summary>
/// 添加一个缓存项，若键已存在则添加失败，add a new item, if exists to failure
/// </summary>
/// <param name="key"></param>
/// <param name="value"></param>
/// <param name="ttl">缓存时间，零值永不过期,单位：秒 <para>ttl, zero is no expired, unit: seconds.</para></param>
/// <returns>success: true, ,key exists: false </returns>
public bool Add(TKey key, TValue value, int ttl)
{
int endTick = 0;
//capacity - 1 differ
if (this.dictionary.Count > this.capacity)
//if (cachedObjects.Count >= capacity)
{
this.RemoveLastUsed();
}
LinkedListNode <LRUCacheItem <TKey, TValue> > node;
if (this.dictionary.TryGetValue(key, out node))
{
if (node.Value.EndTick == 0)
{
return(false);
}
else if (Environment.TickCount - node.Value.EndTick < 0)
{
return(false);
}
else //update
{
if (ttl > 0)
{
endTick = Environment.TickCount + ttl;
}
this.list.Remove(node);
this.list.AddLast(node);
node.Value.ItemValue = value;
node.Value.EndTick = endTick;
return(true);
}
}
if (ttl > 0)
{
endTick = Environment.TickCount + ttl;
}
LRUCacheItem <TKey, TValue> cacheItem = new LRUCacheItem <TKey, TValue>(key, value, endTick);
node = new LinkedListNode <LRUCacheItem <TKey, TValue> >(cacheItem);
this.list.AddLast(node);
this.dictionary.Add(key, node);
return(true);
}