public ISelectExecutor GetSelectExecutor(ExecuteSelectStage selectStage)
{
var t = typeof(DefaultSelectExecutor <,>).MakeGenericType(selectStage.InType, selectStage.OutType);
var executor = (ISelectExecutor)Activator.CreateInstance(t);
return(executor);
}
public async ValueTask <IQueryable> Visit(ExecuteSelectStage executeSelectStage)
{
Debug.Assert(queryable != null);
var selectExecutor = _selectExecutorFactory.GetSelectExecutor(executeSelectStage);
var selectResult = await selectExecutor.Execute(queryable, executeSelectStage);
columns = selectResult.Columns;
return(selectResult.Queryable);
}
protected Expression <Func <InType, OutType> > GetLambda(ExecuteSelectStage selectStage)
{
var lambda = Expression.Lambda <Func <InType, OutType> >(selectStage.Expression, selectStage.ParameterExpression);
return(lambda);
}
public abstract ValueTask <IQueryable <OutType> > ExecuteSelect(IQueryable <InType> queryable, ExecuteSelectStage selectStage);
public async ValueTask <SelectResult> Execute(IQueryable queryable, ExecuteSelectStage selectStage)
{
return(new SelectResult(await ExecuteSelect((IQueryable <InType>)queryable, selectStage), selectStage.Columns));
}
public override ValueTask <IQueryable <OutType> > ExecuteSelect(IQueryable <InType> queryable, ExecuteSelectStage selectStage)
{
return(new ValueTask <IQueryable <OutType> >(queryable.Select(GetLambda(selectStage))));
}
