/* ****************************************************************************************************** *
* --------------------------- HELPING METHODS ------------------------------ *
* ****************************************************************************************************** */
private FunctionInformation BasicAggregateImplementation(MethodCallExpression methodExpression, string functionName, FunctionInformation.FunctionType functionType)
{
int argumentCount = methodExpression.Arguments.Count;
FunctionInformation information = new FunctionInformation()
{
Name = functionName,
Type = functionType,
MeaningfulArguments = new object[1]
};
System.Type argumentType = methodExpression.Arguments[0].Type.GenericTypeArguments[0];
string entityFullName = argumentType.IsInterface ? default(string) : argumentType.FullName;
string fqn = new FullyQualifiedNameVisitor().BringFQN(methodExpression);
fqn = fqn ?? entityFullName + (argumentCount > 1 ? GetSelectorBody(methodExpression.Arguments[1]) : "");
information.MeaningfulArguments[0] = fqn;
information.WhereContribution = argumentCount > 1 ? OQLBuilder.BuildWhereClause(currentContext, methodExpression.Arguments[1], out OQLBuilder oqlBuilder).Trim() : default(string);
Logger.Log(
"Function Information: " + information.ToLog(),
Microsoft.Extensions.Logging.LogLevel.Debug
);
return(information);
}
public override FunctionInformation OrderBy(MethodCallExpression methodExpression)
{
FunctionInformation information = new FunctionInformation
{
Name = "ORDER BY",
MeaningfulArguments = new object[1],
WhereContribution = default(string),
Type = FunctionInformation.FunctionType.Miscellaneous
};
Expression expression = ((LambdaExpression)((UnaryExpression)methodExpression.Arguments[1]).Operand).Body;
if (expression.NodeType == ExpressionType.MemberAccess)
{
information.MeaningfulArguments[0] = ((MemberExpression)expression).Member.Name;
}
else if (expression.NodeType == ExpressionType.Parameter)
{
// Handling cases of OrderBy(a => a)
string fqn = new FullyQualifiedNameVisitor().BringFQN(methodExpression);
string[] splitFQN = fqn.Split('.');
information.MeaningfulArguments[0] = splitFQN[splitFQN.Length - 1];
}
Logger.Log(
"Function Information: " + information.ToLog(),
Microsoft.Extensions.Logging.LogLevel.Debug
);
return(information);
}
public override FunctionInformation Select(MethodCallExpression methodExpression)
{
FunctionInformation information = new FunctionInformation();
Logger.Log(
"Function Information (Select): " + information.ToLog(),
Microsoft.Extensions.Logging.LogLevel.Debug
);
return(information);
}
public override FunctionInformation OrderByDescending(MethodCallExpression methodExpression)
{
FunctionInformation information = OrderBy(methodExpression);
Logger.Log(
"Function Information (Descending): " + information.ToLog(),
Microsoft.Extensions.Logging.LogLevel.Debug
);
return(information);
}
public override FunctionInformation Count(MethodCallExpression methodExpression)
{
FunctionInformation information = BasicAggregateImplementation(methodExpression, "COUNT", FunctionInformation.FunctionType.Aggregate);
// Remove attribute from the COUNT's argument as OQL works on the supposition that the COUNT's argument
// is an entity and it is indexed.
information.MeaningfulArguments[0] = RemoveAttributeAndCheckExistence(information.MeaningfulArguments[0].ToString());
Logger.Log(
"Function Information: " + information.ToLog(),
Microsoft.Extensions.Logging.LogLevel.Debug
);
return(information);
}
private string BuildFunction(FunctionInformation information, out string whereCriteria)
{
StringBuilder builder = new StringBuilder();
whereCriteria = information.WhereContribution;
switch (information.Type)
{
case FunctionInformation.FunctionType.None:
//
// Do nothing
//
break;
case FunctionInformation.FunctionType.Aggregate:
builder.Append(information.Name).Append("(");
for (int i = 0; i < information.MeaningfulArguments.Length; i++)
{
object arg = information.MeaningfulArguments[i];
builder.Append(i > 0 ? Comma + Space : "");
builder.Append(arg.ToString());
}
builder.Append(")");
break;
case FunctionInformation.FunctionType.QueryMethod:
//
// It would would seem that nothing needs to be done here as of yet
//
break;
case FunctionInformation.FunctionType.Miscellaneous:
for (int i = 0; i < information.MeaningfulArguments.Length; i++)
{
object arg = information.MeaningfulArguments[i];
builder.Append(i > 0 ? Comma + Space : "");
builder.Append("this").Append(Dot).Append(arg.ToString());
}
break;
}
return(builder.ToString());
}
private object EvaluateMethodAndCall(MethodCallExpression methodExpression)
{
//
// Halt user from using unsupported operations
//
if (IsUnsupportedQueryMethod(methodExpression.Method.Name))
{
throw new Exception(methodExpression.Method.Name + " feature is not supported.");
}
if (IsUnsupportedAggregate(methodExpression.Method.Name))
{
throw new Exception(methodExpression.Method.Name + " aggregate is not supported.");
}
if (IsUnsupportedMiscellaneous(methodExpression.Method.Name))
{
throw new Exception(methodExpression.Method.Name + " is not supported.");
}
//
// Now let's see what we can do with the stuff we support
//
if (IsSupportedQueryMethod(methodExpression.Method.Name))
{
// Do nothing. Go with the flow.
Logger.Log(methodExpression.Method.Name + " is a supported query method.", Microsoft.Extensions.Logging.LogLevel.Trace);
return(null);
}
if (IsSupportedAggregate(methodExpression.Method.Name))
{
// Keep the aggregate in mind and go with the flow.
Logger.Log(methodExpression.Method.Name + " is a supported aggregate function.", Microsoft.Extensions.Logging.LogLevel.Trace);
if (aggregateFunction == default(string))
{
FunctionInformation information = functionParser.Parse(methodExpression.Method.Name, methodExpression);
//
// If something else needs to be done.
//
aggregateFunction = BuildFunction(information, out string where);
}
else
{
throw new Exception("More than one aggregates are not supported!");
}
return(null);
}
if (IsSupportedMiscellaneous(methodExpression.Method.Name))
{
Logger.Log(methodExpression.Method.Name + " is a supported miscellaneous function.", Microsoft.Extensions.Logging.LogLevel.Trace);
if (miscellaneousOperations.ContainsKey(methodExpression.Method.Name.ToLower()))
{
throw new Exception("More than one " + methodExpression.Method.Name + " is not supported.");
}
else
{
FunctionInformation information = functionParser.Parse(methodExpression.Method.Name, methodExpression);
//
// If something else needs to be done.
//
miscellaneousOperations.Add(
methodExpression.Method.Name.ToLower(),
BuildFunction(information, out string where)
);
}
return(null);
}
if (IsDateTime(methodExpression))
{
Logger.Log("Encountered DateTime in Method Call.", Microsoft.Extensions.Logging.LogLevel.Trace);
whereBuilder
.Append("DateTime('")
.Append(InvokeMethodCall(methodExpression).ToString())
.Append("')");
return('\t');
}
else
{
// We have a method that needs to be invoked and the result needs to be
// returned to the calling method. This method is not part of LINQ. The
// user passed this method for criteria checking.
if (methodExpression.Object != null)
{
}
// [NOTE] : Behavioral methods are still invoked.
try
{
return(InvokeMethodCall(methodExpression));
}
catch (TargetInvocationException tie)
{
Logger.Log(tie, Microsoft.Extensions.Logging.LogLevel.Critical);
}
}
return(null);
}