public Error GetLayerStack(out ILayerStack stack)
{
Error error = null;
if (cachedLayerStack != null)
{
stack = cachedLayerStack;
}
else
{
ILayer <TLayerData>[] layers;
error = GetNewLayers(out layers);
if (error == null)
{
stack = new LayerStack <TLayerData>(logger, layers);
}
else
{
stack = null;
}
}
return(error);
}
/// <summary>
/// Construct a layer stack provider from a set of layer providers.
/// </summary>
/// <param name="logger"></param>
/// <param name="layerProviders">Layer providers for this stack provider. Must be at least one and all must not be null.</param>
public LayerStackProvider(Logger logger, params ILayerProvider <TLayerData>[] layerProviders)
{
if ((layerProviders == null) || (layerProviders.Length == 0))
{
throw new ArgumentException("At least one layer provider must be provided", nameof(layerProviders));
}
for (int i = 0; i < layerProviders.Length; i++)
{
if (layerProviders[i] == null)
{
throw new ArgumentNullException($"Layer provider {i} was null");
}
}
this.layerProviders = layerProviders;
ILayer <TLayerData>[] layers;
Error error = GetNewLayers(out layers);
if (error == null)
{
bool stateless = layers.All(layer => layer is IStatelessLayer <TLayerData>);
if (stateless)
{
cachedLayerStack = new LayerStack <TLayerData>(logger, layers);
}
}
else
{
throw new InvalidOperationException(error.message);
}
this.logger = logger;
}