protected override void Destructor()
{
lock (s_InstanceLock)
{
base.Destructor();
s_Instance = null;
}
}
/// <summary>
/// Tries to generate the specified number of Globally-Unique distributed IDs (GDID) for the supplied sequence name. This method is thread-safe.
/// The method may generate less GUIDs than requested. All IDs come from the same authority
/// </summary>
/// <param name="scopeName">The name of scope where sequences are kept</param>
/// <param name="sequenceName">The name of sequence within the scope for which ID to be obtained</param>
/// <param name="gdidCount">The dsired number of consecutive GDIDs</param>
/// <param name="vicinity">The location on ID counter scale, the authority may disregard this parameter</param>
/// <param name="noLWM">
/// When true, does not start async fetch of the next ID block while the current block reaches low-water-mark.
/// This may not be desired in some short-lived processes.
/// The provider may disregard this flag
/// </param>
/// <returns>The GDID instance array which may be shorter than requested</returns>
public GDID[] TryGenerateManyConsecutiveGDIDs(string scopeName, string sequenceName, int gdidCount, ulong?vicinity = GDID.COUNTER_MAX, bool noLWM = false)
{
if (scopeName == null || sequenceName == null)
{
throw new GDIDException(StringConsts.ARGUMENT_ERROR + GetType().Name + ".TryGenerateManyConsecutiveGDIDs(scopeName|sequenceName=null)");
}
if (gdidCount <= 0)
{
throw new GDIDException(StringConsts.ARGUMENT_ERROR + GetType().Name + ".TryGenerateManyConsecutiveGDIDs(gdidCount<=0)");
}
if (m_ScopePrefix != null)
{
scopeName = m_ScopePrefix + scopeName;
}
if (m_SequencePrefix != null)
{
sequenceName = m_SequencePrefix + sequenceName;
}
scopeName = scopeName.Trim();
sequenceName = sequenceName.Trim();
GDIDAuthorityService.CheckNameValidity(scopeName);
GDIDAuthorityService.CheckNameValidity(sequenceName);
var scope = m_Scopes.GetOrRegister(scopeName, (snm) => new scope {
Name = snm
}, scopeName);
var sequence = scope.Sequences.GetOrRegister(sequenceName, (_) => new sequence {
Scope = scope, Name = sequenceName
}, 0); //with block=NULL
lock (sequence)
{
var block = sequence.Block;
if (block == null || block.__Remaining <= (gdidCount / 2))//get whole block
{
block = allocateBlock(sequence, gdidCount, vicinity);
block.__Remaining = block.BlockSize;
}
var result = new GDID[Math.Min(gdidCount, block.__Remaining)];
for (var i = 0; i < result.Length; i++, block.__Remaining--)
{
var counter = block.StartCounterInclusive + (ulong)(block.BlockSize - block.__Remaining);
result[i] = new GDID(block.Era, block.Authority, counter);
}
return(result);
}//lock
}
/// <summary>
/// Creates a singleton instance or throws if instance is already created
/// </summary>
public GDIDAuthorityService() : base()
{
lock (s_InstanceLock)
{
if (s_Instance != null)
{
throw new GDIDException(StringConsts.GDIDAUTH_INSTANCE_ALREADY_ALLOCATED_ERROR);
}
s_Instance = this;
}
}
/// <summary>
/// Generates a single Globally-Unique distributed ID (GDID) for the supplied sequence name. This method is thread-safe.
/// The algorithm also respects LWM value, once the number of free counters gets below LWM the asynchronous non-blocking acquisition from authority is triggered
/// </summary>
/// <param name="scopeName">The name of scope where sequences are kept</param>
/// <param name="sequenceName">The name of sequence within the scope for which ID to be obtained</param>
/// <param name="blockSize">If >0 requests to pre-allocate specified number of sequences, otherwise the generator will pre-allocate the most suitable/configured size</param>
/// <param name="vicinity">The location on ID counter scale, the authority may disregard this parameter</param>
/// <param name="noLWM">
/// When true, does not start async fetch of the next ID block while the current block reaches low-water-mark.
/// This may not be desired in some short-lived processes.
/// The provider may disregard this flag
/// </param>
/// <returns>The GDID instance</returns>
public GDID GenerateOneGDID(string scopeName, string sequenceName, int blockSize = 0, ulong?vicinity = GDID.COUNTER_MAX, bool noLWM = false)
{
if (scopeName == null || sequenceName == null)
{
throw new GDIDException(StringConsts.ARGUMENT_ERROR + GetType().Name + ".GenerateOneGDID(scopeName|sequenceName=null)");
}
if (m_ScopePrefix != null)
{
scopeName = m_ScopePrefix + scopeName;
}
if (m_SequencePrefix != null)
{
sequenceName = m_SequencePrefix + sequenceName;
}
scopeName = scopeName.Trim();
sequenceName = sequenceName.Trim();
GDIDAuthorityService.CheckNameValidity(scopeName);
GDIDAuthorityService.CheckNameValidity(sequenceName);
var scope = m_Scopes.GetOrRegister(scopeName, (snm) => new scope {
Name = snm
}, scopeName);
var sequence = scope.Sequences.GetOrRegister(sequenceName, (_) => new sequence {
Scope = scope, Name = sequenceName
}, 0); //with block=NULL
lock (sequence)
{
var block = sequence.Block;
if (block == null || block.__Remaining <= 0) //need to get Next
{
block = sequence.NextBlock; //atomic
if (block == null)
{
block = allocateBlock(sequence, blockSize, vicinity);
}
else
{
sequence.NextBlock = null;
sequence.FetchingNextBlock = null;
}
sequence.Block = block;
block.__Remaining = block.BlockSize;
}
var counter = block.StartCounterInclusive + (ulong)(block.BlockSize - block.__Remaining);
block.__Remaining--;
var result = new GDID(block.Era, block.Authority, counter);
//check LWM
if (!noLWM && block.BlockSize > 7 && sequence.FetchingNextBlock == null)
{
double curlvl = (double)block.__Remaining / (double)block.BlockSize;
if (curlvl <= BLOCK_LOW_WATER_MARK) //start fetching next block
{
sequence.FetchingNextBlock = Task.Factory.StartNew(() =>
{
try
{
var nextBlock = allocateBlock(sequence, blockSize, vicinity);
sequence.NextBlock = nextBlock;//atomic assignment
}
catch (Exception error)
{ //todo Perf counter
log(MessageType.Error, GetType().Name + ".Generate().Task{}", "Error getting NextBlock", error);
}
});
}
}
return(result);
}//lock
}
