/// <summary>
/// Allocate an object from the pool.
/// </summary>
/// <remarks>
/// <para>
/// If there are idle instances available in the pool, the first element is activated, and
/// return to the client.
/// If there are no idle instances available, <see cref="IObjectFactory{T}.Make" /> is invoked to create a
/// new instance.
/// </para>
/// <para>
/// All instances are <see cref="IObjectFactory{T}.Activate" /> before being returned to the client. If the
/// instances fail the activation, it will be destoryed.
/// </para>
/// <para>
/// Exceptions throws by <see cref="IObjectFactory{T}.Activate" /> or
/// <see cref="IObjectFactory{T}.Destory" /> instances are silently swallowed.
/// </para>
/// </remarks>
/// <returns>An instance from the pool.</returns>
/// <exception cref="Exception">
/// When <see cref="IObjectFactory{T}.Make" /> or
/// <see cref="IObjectFactory{T}.Make" /> throws an exception.
/// </exception>
public override T Allocate()
{
var obj = _firstItem;
// Try to get first item
if (obj == null || obj != Interlocked.CompareExchange(ref _firstItem, null, obj))
{
obj = SlowAllocate(); // Failed to get from first item, use slower method instead.
}
else
{
// Success to get from first item,
try
{
// Activate object
_factory.Activate(obj);
}
catch (Exception activateException)
{
// Failed activation
// Check the exception rethrow setting
CheckExceptionRethrow(activateException);
try
{
// Destroy object
_factory.Destory(obj);
}
catch (Exception destoryException)
{
// Failed to destroy
// Check the exception rethrow setting
CheckExceptionRethrow(destoryException);
}
// Failed to get from first item, use slower method instead.
obj = SlowAllocate();
}
}
return(obj);
}
/// <summary>
/// Allocate an object from the pool.
/// </summary>
/// <remarks>
/// <para>
/// If there are idle instances available on the stack, the top element of the stack is popped to activate, and
/// return to the client.
/// If there are no idle instances available, <see cref="IObjectFactory{T}.Make" /> is invoked to create a
/// new instance.
/// </para>
/// <para>
/// All instances are <see cref="IObjectFactory{T}.Activate" /> before being returned to the client.
/// </para>
/// </remarks>
/// <returns>An instance from the pool.</returns>
/// <exception cref="Exception">
/// When <see cref="IObjectFactory{T}.Make" /> or
/// <see cref="IObjectFactory{T}.Make" /> throws an exception.
/// </exception>
public override T Allocate()
{
T obj = null;
while (obj == null)
{
// Try to get cached object from stack
if (_pool.Count > 0)
{
obj = _pool.Pop();
try
{
// Activate object
_factory.Activate(obj);
}
catch (Exception activateException)
{
// Failed activation
// Check the exception rethrow setting
CheckExceptionRethrow(activateException);
try
{
// Destroy object
_factory.Destory(obj);
}
catch (Exception destoryException)
{
// Failed to destroy
// Check the exception rethrow setting
CheckExceptionRethrow(destoryException);
}
}
finally
{
obj = null;
}
}
else
{
// Failed to get cached object, create a new one
obj = _factory.Make();
if (obj == null)
{
throw new Exception("Factory failed to create a object.");
}
}
}
return(obj);
}