// Fetch an object from backing store if not cached, serve from
// cache if it is.
//
public virtual Object Get(string index, FetchDelegate fetch)
{
CacheItemBase item = GetItem(index);
if (item != null)
{
return(item.Retrieve());
}
Object data = fetch(index);
if (data == null)
{
if ((m_Flags & CacheFlags.CacheMissing) != 0)
{
lock (m_Index)
{
CacheItemBase missing = new CacheItemBase(index);
if (!m_Index.Contains(missing))
{
m_Index.Add(missing);
m_Lookup[index] = missing;
}
}
}
return(null);
}
Store(index, data);
return(data);
}
// Get an item from cache. Return the raw item, not it's data
//
protected virtual CacheItemBase GetItem(string index)
{
CacheItemBase item = null;
lock (m_Index)
{
if (m_Lookup.ContainsKey(index))
{
item = m_Lookup[index];
}
if (item == null)
{
Expire(true);
return(null);
}
item.hits++;
item.lastUsed = DateTime.UtcNow;
Expire(true);
}
return(item);
}
// Get an item from cache. Do not try to fetch from source if not
// present. Just return null
//
public virtual Object Get(string index)
{
CacheItemBase item = GetItem(index);
if (item == null)
{
return(null);
}
return(item.Retrieve());
}
// Find an object in cache by delegate.
//
public Object Find(Predicate <CacheItemBase> d)
{
CacheItemBase item = m_Index.Find(d);
if (item == null)
{
return(null);
}
return(item.Retrieve());
}
public void Invalidate(string uuid)
{
if (!m_Lookup.ContainsKey(uuid))
{
return;
}
CacheItemBase item = m_Lookup[uuid];
m_Lookup.Remove(uuid);
m_Index.Remove(item);
}
// Get an item from cache. Return the raw item, not it's data
//
protected virtual CacheItemBase GetItem(string index)
{
CacheItemBase item = null;
m_IndexRwLock.AcquireReaderLock(-1);
try
{
if (m_Lookup.ContainsKey(index))
{
item = m_Lookup[index];
}
if (item == null)
{
LockCookie lc = m_IndexRwLock.UpgradeToWriterLock(-1);
try
{
Expire(true);
}
finally
{
m_IndexRwLock.DowngradeFromWriterLock(ref lc);
}
return(null);
}
item.hits++;
item.lastUsed = DateTime.Now;
{
LockCookie lc = m_IndexRwLock.UpgradeToWriterLock(-1);
try
{
Expire(true);
}
finally
{
m_IndexRwLock.DowngradeFromWriterLock(ref lc);
}
}
}
finally
{
m_IndexRwLock.ReleaseReaderLock();
}
return(item);
}
public void Invalidate(string uuid)
{
m_IndexRwLock.AcquireWriterLock(-1);
try
{
if (!m_Lookup.ContainsKey(uuid))
{
return;
}
CacheItemBase item = m_Lookup[uuid];
m_Lookup.Remove(uuid);
m_Index.Remove(item);
}
finally
{
m_IndexRwLock.ReleaseWriterLock();
}
}
// Fetch an object from backing store if not cached, serve from
// cache if it is.
//
public virtual Object Get(string index, FetchDelegate fetch)
{
Object item = Get(index);
if (item != null)
{
return(item);
}
Object data = fetch(index);
if (data == null)
{
if ((m_Flags & CacheFlags.CacheMissing) != 0)
{
m_IndexRwLock.AcquireWriterLock(-1);
try
{
CacheItemBase missing = new CacheItemBase(index);
if (!m_Index.Contains(missing))
{
m_Index.Add(missing);
m_Lookup[index] = missing;
}
}
finally
{
m_IndexRwLock.ReleaseWriterLock();
}
}
return(null);
}
Store(index, data);
return(data);
}
