public DedupingQueueAddResult AddItem(T item)
{
lock (itemSync)
{
string tokenValue = GetToken(item);
DedupingQueueItemWrapper <T> wrappedItem;
if (tokenValue != null && itemsWithTokens.TryGetValue(tokenValue, out wrappedItem)) //if token is already in queue then just swap.
{
wrappedItem.Item = item;
return(DedupingQueueAddResult.Duplicate);
}
//if no more room than item is dropped
if (maxCapacity != null && queue.Count >= maxCapacity.Value)
{
return(DedupingQueueAddResult.QueueFull);
}
DedupingQueueItemWrapper <T> transientItemWrapper = new DedupingQueueItemWrapper <T>(item);
queue.Enqueue(transientItemWrapper);
if (tokenValue != null)
{
itemsWithTokens[tokenValue] = transientItemWrapper;
}
return(DedupingQueueAddResult.NewItem);
}
}
/// <summary>
/// Retrieves the next item if there is one.
/// </summary>
/// <param name="item">output parameter to receive the dequeued item</param>
/// <returns>true if an item has been retrieved, false if the queue was empty.</returns>
public bool Dequeue(out T item) //using an output parameter rather than the return value for the dequeued item supports T being a value type.
{
item = default(T);
lock (itemSync)
{
if (queue.Count > 0)
{
DedupingQueueItemWrapper <T> dequeuedItemWrapper = queue.Dequeue();
item = dequeuedItemWrapper.Item;
String idToken = GetToken(item);
if (idToken != null)
{
itemsWithTokens.Remove(idToken);
}
return(true);
}
else
{
return(false);
}
}
}
