/// <summary>
/// Thread-safe method to obtain singleton instance of <see cref="ICacheProvider"/>
/// matching specified filter.
/// </summary>
/// <param name="filter"></param>
/// <returns></returns>
private static ICacheProvider GetProvider(Predicate <ExtensionInfo> filter)
{
// determine the provider class
var point = new CacheProviderExtensionPoint();
var extension = CollectionUtils.FirstElement(point.ListExtensions(filter));
if (extension == null)
{
throw new CacheException("No cache provider extension found, or those that exist do not support all required features.");
}
var providerClass = extension.ExtensionClass.Resolve();
// check if we already have an initialized instance of this provider class.
ICacheProvider provider;
if (!_providers.TryGetValue(providerClass, out provider))
{
// if not, create one
lock (_providers)
{
// ensure that another thread hasn't beat us to it
if (!_providers.TryGetValue(providerClass, out provider))
{
provider = (ICacheProvider)point.CreateExtension(
new ClassNameExtensionFilter(providerClass.FullName));
// initialize this provider and store it
provider.Initialize(new CacheProviderInitializationArgs());
_providers.Add(providerClass, provider);
}
}
}
return(provider);
}
/// <summary>
/// Thread-safe method to obtain singleton instance of <see cref="ICacheProvider"/>
/// matching specified filter.
/// </summary>
/// <param name="filter"></param>
/// <returns></returns>
private static ICacheProvider GetProvider(Predicate <ExtensionInfo> filter)
{
// determine the provider class
var point = new CacheProviderExtensionPoint();
var extension = CollectionUtils.FirstElement(point.ListExtensions(filter));
if (extension == null)
{
throw new CacheException("No cache provider extension found, or those that exist do not support all required features.");
}
var providerClass = extension.ExtensionClass.Resolve();
return(_providers.GetOrAdd(providerClass, k =>
{
// initialize this provider and store it
var provider = (ICacheProvider)point.CreateExtension(new ClassNameExtensionFilter(providerClass.FullName));
provider.Initialize(new CacheProviderInitializationArgs());
return provider;
}));
}