public static IChangeSet <TObject, TKey> RefreshFilteredFrom <TObject, TKey>(this ChangeAwareCache <TObject, TKey> filtered, Cache <TObject, TKey> allData, Func <TObject, bool> predicate)
where TKey : notnull
{
if (allData.Count == 0)
{
return(ChangeSet <TObject, TKey> .Empty);
}
foreach (var kvp in allData.KeyValues)
{
var existing = filtered.Lookup(kvp.Key);
var matches = predicate(kvp.Value);
if (matches)
{
if (!existing.HasValue)
{
filtered.Add(kvp.Value, kvp.Key);
}
}
else
{
if (existing.HasValue)
{
filtered.Remove(kvp.Key);
}
}
}
return(filtered.CaptureChanges());
}
public static void FilterChanges <TObject, TKey>(this ChangeAwareCache <TObject, TKey> cache,
IChangeSet <TObject, TKey> changes,
Func <TObject, bool> predicate)
{
var concreteType = changes.ToConcreteType();
foreach (var change in concreteType)
{
var key = change.Key;
switch (change.Reason)
{
case ChangeReason.Add:
{
var current = change.Current;
if (predicate(current))
{
cache.Add(current, key);
}
}
break;
case ChangeReason.Update:
{
var current = change.Current;
if (predicate(current))
{
cache.AddOrUpdate(current, key);
}
else
{
cache.Remove(key);
}
}
break;
case ChangeReason.Remove:
cache.Remove(key);
break;
case ChangeReason.Refresh:
{
var exisiting = cache.Lookup(key);
if (predicate(change.Current))
{
if (!exisiting.HasValue)
{
cache.AddOrUpdate(change.Current, key);
}
else
{
cache.Refresh(key);
}
}
else
{
if (exisiting.HasValue)
{
cache.Remove(key);
}
}
}
break;
}
}
}