protected override IEnumerable GetEntities(IEnumerable <string> identifiers)
{
var identifiersToRequest = identifiers.Except(_savable.GetAllPendingChangesIdentifiers());
var entities = GetEntitiesFromCache(identifiers);
return(_savable.CombineWithPendingChanges(entities, _predicate));
}
protected override IEnumerable <string> GetIdentifiersToRequest()
{
// here we need to get entities from cache, execute the expression on them,
// get the result and grab only identifiers from the result;
// read all entites from cache
var entites = _cachedDataProvider.GetCachedEntities();
// merge with the all the pending changes
var mergedEntities = _savable.CombineWithPendingChanges(entites, null);
var queryableEntities = mergedEntities.AsQueryable();
// execute expression on the cached entities
var newExpressionTree = ModifyExpressionAndReturnResult(_expressionInfo.OriginalExpression, queryableEntities);
object result;
if (_expressionInfo.IsEnumerableResult)
{
result = queryableEntities.Provider.CreateQuery(newExpressionTree);
}
else
{
result = queryableEntities.Provider.Execute(newExpressionTree);
}
if (result == null)
{
return(Enumerable.Empty <string>());
}
if (result is T item)
{
return new[] { _keyGetter(item) }
}
;
if (result is IEnumerable <T> items)
{
return(items.Select(_keyGetter));
}
throw new NotSupportedException($"Expression is not supported");
}
protected override IEnumerable GetEntities(IEnumerable <string> identifiers)
{
var method = _expressionInfo.InnerMostExpression.Method;
if (!IsNonReplacableMethod(method))
{
return(_savable.CombineIdentifiersRangeWithPendingChanges(identifiers, _predicate));
}
// non - replacable methods, we need entities
var identifiersToRequest = identifiers.Except(_savable.GetAllPendingChangesIdentifiers());
// assume we can just get if from the cache directly for no other properties except key are used.
var entities = identifiersToRequest.Any() ? _cachedDataProvider.GetCachedEntities(identifiersToRequest) : Enumerable.Empty <T>();
//var entities = identifiersToRequest.Any() ? _cachedDataProvider.GetEntitiesBasedOnCache(identifiersToRequest) : Enumerable.Empty<T>();
return(_savable.CombineWithPendingChanges(entities, _predicate));
}
protected override IEnumerable GetEntities(IEnumerable <string> identifiers)
{
IEnumerable <T> entities;
if (identifiers == null)
{
entities = GetAllEntitiesFromDao();
}
else if (!identifiers.Any())
{
entities = Enumerable.Empty <T>();
}
else
{
var identifiersToRequest = identifiers.Except(_savable.GetAllPendingChangesIdentifiers());
entities = identifiersToRequest.Any() ? GetEntitiesFromDao(identifiersToRequest) : Enumerable.Empty <T>();
}
return(_savable.CombineWithPendingChanges(entities, _predicate));
}
