/// <summary>
/// 创建一个自定义的缓存优先级
/// </summary>
/// <param name="priority">预制优先级，当缓存提供程序无法识别缓存优先级提示时使用</param>
/// <param name="hint">缓存优先级提示信息，特定的缓存提供程序可以读取该信息使用最合适的优先级</param>
/// <returns></returns>
public CachePriority CreatePriority( CachePriority priority, string hint )
{
if ( priority._hint != null )
throw new ArgumentException( "priority" );
return new CachePriority( priority._priorityValue, hint );
}
/// <summary>
/// 创建一个自定义的缓存优先级
/// </summary>
/// <param name="priority">预制优先级，当缓存提供程序无法识别缓存优先级提示时使用</param>
/// <param name="hint">缓存优先级提示信息，特定的缓存提供程序可以读取该信息使用最合适的优先级</param>
/// <returns></returns>
public CachePriority CreatePriority(CachePriority priority, string hint)
{
if (priority._hint != null)
{
throw new ArgumentException("priority");
}
return(new CachePriority(priority._priorityValue, hint));
}
/// <summary>
/// 创建缓存策略
/// </summary>
/// <param name="expires">过期时间</param>
/// <param name="dependencies">缓存依赖项</param>
/// <param name="priority">缓存优先级</param>
public CachePolicyItem(DateTime expires, CacheDependency dependencies = null, CachePriority priority = default(CachePriority))
{
if (expires.Kind != DateTimeKind.Utc)
{
throw new ArgumentException("expires must be an UTC time.", "expires");
}
Expires = expires;
Priority = priority;
Dependencies = dependencies;
}
public static CachePolicyProviderWithPriority Create(CachePolicy policy, CachePriority priority)
{
var withPriority = policy as CachePolicyProviderWithPriority;
if (withPriority != null)
{
return(new CachePolicyProviderWithPriority(withPriority._policy, priority));
}
else
{
return(new CachePolicyProviderWithPriority(policy, priority));
}
}
/// <summary>
/// 从字符串中解析出缓存策略对象
/// </summary>
/// <param name="str">要解析的字符串</param>
/// <returns>缓存策略对象</returns>
public static CachePolicyItem Parse(string str)
{
if (str == null)
{
throw new ArgumentNullException(str);
}
var data = str.Split(',');
if (data.Length != 2)
{
throw new FormatException();
}
var expires = long.Parse(data[0]);
var prioroty = CachePriority.Parse(data[1]);
return(new CachePolicyItem(new DateTime(expires, DateTimeKind.Utc), null, prioroty));
}
/// <summary>
/// 重写 Equals 方法，比较两个缓存优先级对象（注意，只要预置的优先级一样，就会判定两个对象相同，将忽略缓存优先级提示信息）
/// </summary>
/// <param name="priority">要比较的对象</param>
/// <returns>是否具有同等的优先级</returns>
public bool Equals(CachePriority priority)
{
return(priority._priorityValue == this._priorityValue);
}
private CachePolicyProviderWithPriority(CachePolicy policy, CachePriority priority)
{
_policy = policy;
_priority = priority;
}
/// <summary>
/// 创建一个新的缓存策略，使用指定的优先级
/// </summary>
/// <param name="priority">默认缓存优先级</param>
/// <returns>应用了默认缓存优先级的缓存策略提供程序</returns>
public CachePolicy WithPriority(CachePriority priority)
{
return(CachePolicyProviderWithPriority.Create(this, priority));
}
/// <summary>
/// 重写 Equals 方法，比较两个缓存优先级对象（注意，只要预置的优先级一样，就会判定两个对象相同，将忽略缓存优先级提示信息）
/// </summary>
/// <param name="priority">要比较的对象</param>
/// <returns>是否具有同等的优先级</returns>
public bool Equals( CachePriority priority )
{
return priority._priorityValue == this._priorityValue;
}
/// <summary>
/// 将缓存优先级设置为自定义优先级
/// </summary>
/// <param name="priority">自定义优先级</param>
/// <returns>设置为自定义优先级之后的缓存策略</returns>
public CachePolicyItem SetPriority(CachePriority priority)
{
return(new CachePolicyItem(Expires, Dependencies, priority));
}