/**
* Returns the current maximum Message position within the given Conversation, or
* Long.MIN_VALUE if no messages are found.
*
* @param conversationId Conversation whose maximum Message position to return.
* @return the current maximum Message position or Long.MIN_VALUE.
*/
private long GetMaxPosition(Uri conversationId)
{
LayerClient layerClient = App.GetLayerClient();
LayerQuery query = LayerQuery.InvokeBuilder(Java.Lang.Class.FromType(typeof(IMessage)))
.Predicate(new Predicate(MessageProperty.Conversation, Predicate.Operator.EqualTo, conversationId))
.SortDescriptor(new SortDescriptor(MessageProperty.Position, SortDescriptor.Order.Descending))
.Limit(1)
.Build();
IList <IQueryable> results = layerClient.ExecuteQueryForObjects(query);
if (results.Count == 0)
{
return(long.MinValue);
}
var message = results[0] as IMessage;
if (message == null)
{
return(long.MinValue);
}
return(message.Position);
}