/// <summary>
/// Get the specify record
/// </summary>
public PersistanceItemInfo Get(string key)
{
DbCommand cmd = _conn.CreateCommand();
cmd.CommandText =
"select ItemKey,DataRecordPosition,ContentLength,LastModifyTime,Properties" +
" from BlockInfo" +
" where ItemKey=@ItemKey;";
DbParameter para1 = cmd.CreateParameter();
para1.ParameterName = "@ItemKey";
para1.Value = key;
cmd.Parameters.Add(para1);
using (DbDataReader reader = cmd.ExecuteReader())
{
if (reader.Read())
{
PersistanceItemInfo item = new PersistanceItemInfo();
item.Key = reader.GetString(0);
item.DataRecordPosition = reader.GetInt64(1);
item.ContentLength = reader.GetInt32(2);
item.ItemTime = reader.GetDateTime(3);
item.Properties = reader.GetInt32(4);
return(item);
}
else
{
throw new StoringException("The specify item not found");
}
}
}
/// <summary>
/// Store or update item
/// </summary>
public void Store(CacheItem item)
{
if (!_enableStoring)
{
throw new InvalidOperationException("Does not support storing");
}
lock (_syncObject)
{
try
{
PersistanceItemInfo info = _indexAccess.Get(item.Key);
//update old record
_dataAccess.Update(info.DataRecordPosition, item.Content, item.Content.Length);
_indexAccess.Update(
item.Key, item.Content.Length,
item.ItemTime, item.Properties);
}
catch (StoringException)
{
//and new record
long position = _dataAccess.Add(item.Content);
PersistanceItemInfo info2 = new PersistanceItemInfo()
{
Key = item.Key,
ContentLength = item.Content.Length,
DataRecordPosition = position,
ItemTime = item.ItemTime,
Properties = item.Properties
};
_indexAccess.Add(info2);
}
}
}
/// <summary>
/// Add a new record
/// </summary>
public void Add(PersistanceItemInfo item)
{
DbCommand cmd = _conn.CreateCommand();
cmd.CommandText = "insert into BlockInfo" +
" (ItemKey,DataRecordPosition,ContentLength,LastModifyTime,Properties)" +
" values (@ItemKey,@DataRecordPosition,@ContentLength,@LastModifyTime,@Properties);";
DbParameter para1 = cmd.CreateParameter();
DbParameter para2 = cmd.CreateParameter();
DbParameter para3 = cmd.CreateParameter();
DbParameter para4 = cmd.CreateParameter();
DbParameter para5 = cmd.CreateParameter();
para1.ParameterName = "@ItemKey";
para1.Value = item.Key;
para2.ParameterName = "@DataRecordPosition";
para2.Value = item.DataRecordPosition;
para3.ParameterName = "@ContentLength";
para3.Value = item.ContentLength;
para4.ParameterName = "@LastModifyTime";
para4.Value = item.ItemTime;
para5.ParameterName = "@Properties";
para5.Value = item.Properties;
cmd.Parameters.Add(para1);
cmd.Parameters.Add(para2);
cmd.Parameters.Add(para3);
cmd.Parameters.Add(para4);
cmd.Parameters.Add(para5);
cmd.ExecuteNonQuery();
}
/// <summary>
/// Fetch cache infomation and content
/// </summary>
public CacheItem Fetch(string key)
{
//NOTE::
// if the specify cache doesn't exist, this procedure will throw exception
if (!_enableStoring)
{
throw new InvalidOperationException("Does not support storing");
}
lock (_syncObject)
{
PersistanceItemInfo info = _indexAccess.Get(key);
byte[] data = new byte[info.ContentLength];
_dataAccess.Get(info.DataRecordPosition, data, data.Length);
CacheItem item = new CacheItem(
key, data, info.ItemTime, info.Properties);
return(item);
}
}