private ObjectPoolSegment <T> CreateSegment(bool allowSegmentToBeCleanedUp)
{
if (_disposed)
{
throw new ObjectDisposedException("ObjectPoolBase");
}
// This method is called inside a lock, so no interlocked stuff required.
int segmentToAdd = _activeSegment;
_activeSegment++;
Queue <T> buffers = new Queue <T>();
for (int i = 1; i <= this._itemsPerSegment; i++)
{
T obj = GetObjectInstance();
buffers.Enqueue(obj);
}
// certain segments we don't want to ever be cleaned up (the initial segments)
DateTime cleanupTime = (allowSegmentToBeCleanedUp) ? DateTime.Now.Add(this._minimumAgeToCleanup) : DateTime.MaxValue;
ObjectPoolSegment <T> segment = new ObjectPoolSegment <T>(segmentToAdd, buffers, cleanupTime);
return(segment);
}
/// <summary>
/// Checks in an instance of T owned by the object pool. This method is only intended to be called
/// by the <c>WrappedObject</c> class.
/// </summary>
/// <param name="owningSegment">The segment from which the instance is checked out.</param>
/// <param name="instance">The instance of <c>T</c> to check back into the segment.</param>
internal void CheckIn(ObjectPoolSegment <T> owningSegment, T instance)
{
lock (_syncRoot)
{
owningSegment.CheckInObject(instance);
}
}
protected void Initialize(int itemsPerSegment, int minimumSegmentCount, bool gcOnPoolGrowth, int cleanupFrequenceMS)
{
_itemsPerSegment = itemsPerSegment;
_minimumSegmentCount = minimumSegmentCount;
_gc = gcOnPoolGrowth;
// force garbage collection to make sure these new long lived objects
// cause as little fragmentation as possible
if (_gc)
{
System.GC.Collect();
}
lock (_syncRoot)
{
while (_segments.Count < this.MinimumSegmentCount)
{
ObjectPoolSegment <T> segment = CreateSegment(false);
_segments.Add(segment.SegmentNumber, segment);
}
}
// This forces a compact, to make sure our objects fill in any holes in the heap.
if (_gc)
{
System.GC.Collect();
}
_timer = new Timer(CleanupThreadCallback, null, cleanupFrequenceMS, cleanupFrequenceMS);
}
/// <summary>
/// Checks an instance of <c>T</c> from the pool. If the pool is not sufficient to
/// allow the checkout, a new segment is created.
/// </summary>
/// <returns>A <c>WrappedObject</c> around the instance of <c>T</c>. To check
/// the instance back into the segment, be sureto dispose the WrappedObject
/// when finished. </returns>
public WrappedObject <T> CheckOut()
{
if (_disposed)
{
throw new ObjectDisposedException("ObjectPoolBase");
}
// It's key that this CheckOut always, always, uses a pooled object
// from the oldest available segment. This will help keep the "newer"
// segments from being used - which in turn, makes them eligible
// for deletion.
lock (_syncRoot)
{
ObjectPoolSegment <T> targetSegment = null;
// find the oldest segment that has items available for checkout
for (int i = 0; i < _activeSegment; i++)
{
ObjectPoolSegment <T> segment;
if (_segments.TryGetValue(i, out segment) == true)
{
if (segment.AvailableItems > 0)
{
targetSegment = segment;
break;
}
}
}
if (targetSegment == null)
{
// We couldn't find a sigment that had any available space in it,
// so it's time to create a new segment.
// Before creating the segment, do a GC to make sure the heap
// is compacted.
if (_gc)
{
GC.Collect();
}
targetSegment = CreateSegment(true);
if (_gc)
{
GC.Collect();
}
_segments.Add(targetSegment.SegmentNumber, targetSegment);
}
WrappedObject <T> obj = new WrappedObject <T>(this, targetSegment, targetSegment.CheckOutObject());
return(obj);
}
}
internal WrappedObject(ObjectPoolBase <T> owningPool, ObjectPoolSegment <T> ownerSegment, T activeInstance)
{
_owningObjectPool = owningPool;
_owningSegment = ownerSegment;
_instance = activeInstance;
}
