private bool CheckTimeout(DbLuceneLock dbLock)
{
DateTime now = DateTime.UtcNow;
if (dbLock.ExpireTimeUTC < now)
{
return(true);
}
return(false);
}
public override void Release()
{
DbLuceneLock dbLock = _db.LuceneLockSet.SingleOrDefault(obj => obj.LockName.Equals(_lockName) && obj.LockSource.Equals(_srcGuid));
if (dbLock == null)
{
return;
}
_db.LuceneLockSet.Remove(dbLock);
_db.SaveChanges();
}
public override bool IsLocked()
{
// Check lockName only. The lock may be from another source.
DbLuceneLock dbLock = _db.LuceneLockSet.SingleOrDefault(obj => obj.LockName.Equals(_lockName));
if (dbLock == null)
{
return(false);
}
// If the lock is timeout. Just release it.
bool timeout = CheckTimeout(dbLock);
if (timeout)
{
return(false);
}
return(true);
}
/// <summary>
/// DbLuceneLock啟用Optimistic Locking的機制。如果該lock object有多個人修改，會造成Exception。以此處理concurrency的問題。
/// </summary>
/// <returns></returns>
public override bool Obtain()
{
DbLuceneLock dbLock = _db.LuceneLockSet.SingleOrDefault(obj => obj.LockName.Equals(_lockName));
if (dbLock != null && CheckTimeout(dbLock) == false)
{
return(false);
}
if (dbLock == null)
{
dbLock = new DbLuceneLock(_lockName);
dbLock.LockSource = _srcGuid;
dbLock.ExpireTimeUTC = DateTime.UtcNow.Add(_expireOffset);
_db.LuceneLockSet.Add(dbLock);
_db.SaveChanges();
return(true);
}
dbLock.LockSource = _srcGuid;
dbLock.ExpireTimeUTC = DateTime.UtcNow.Add(_expireOffset);
_db.SaveChanges();
return(true);
}
