private IObservable <INode> Fetcher(Guid id)
{
return(Observable.Defer(() =>
{
INode node;
return NodeCache.TryGetValue(id, out node)
? Observable.Return(node)
: _lazyStorage.Value.Fetch(id).Do(x => NodeCache[id] = x);
}));
}
public IObservable <INode> Fetch(IObservable <Guid> ids)
{
return(Observable
.CreateWithDisposable <INode>(observer =>
ids.Subscribe(x =>
{
INode node;
if (NodeCache.TryGetValue(x, out node))
{
observer.OnNext(node);
}
else
{
node = _lazyStorage.Value.Fetch(x);
NodeCache[x] = node;
observer.OnNext(node);
}
}, observer.OnError, observer.OnCompleted)));
}