With the nDepend API, would something like the following be possible?
I want to keep a watch out for instances where our object factory has been bypassed and a concrete class is being instantiated directly.
Obviously I'd need to be able to filter out things like:
StringBuilder stringBuilder = new StringBuilder();
perhaps by adding to the Where clause type names to exclude, or namespaces in which to check, but I want to make sure we see:
IMyCustomType item = ObjectFactory.Get<IMyCustomType>();
and not this:
MyCustomType item = new MyCustomType();
Thanks.
Maybe such code rule below could help you, hopefully it is understandable enough to not have to comment it:
warnif count > 0
let ctors = Application.Namespaces.WithNameLike("Namespaces1*").ChildMethods().Where(m => m.IsConstructor)
let codeThatMustNotCallCtors = Application.Namespaces.WithNameLike("Namespaces2*").ChildMethods()
from m in codeThatMustNotCallCtors.UsingAny(ctors)
select new { m, ctorsCalled = m.MethodsCalled.Intersect(ctors ) }
Related
I'm trying to use Drools with Scala and i would like to know if it is possible to call a chain of events and create var/val when the function has a return.
Here is what i'm trying but i'm stuck:
import com.models.*
import com.service.*
rule "First Fule"
when
person:Person(name == 'aa')
then
//Here should return a string
//and i should set this string
//something like:
//var x = new Person(ServiceLongDong.sayHello(), person.age, person.name)
//or var y = ServiceLongDong.sayHello();
ServiceLongDong.sayHello();
ServiceLongDong.finish(x);
end
Is possible to create varl/vals and pass it to another function?
Thank in advance.
Rules aren't functions (or methods) and don't "return" values or objects. The right hand side is just Java code. You can call static methods, but stick to correct Java syntax:
Person p = new Person(ServiceLongDong.sayHello(),
person.age, person.name);
ServiceLongDong.sayHello();
ServiceLongDong.finish(x);
This can't be correct Java if ServiceLongDong is a class:
... = ServiceLongDong().sayHello();
Hi,
I'm developing an Eclipse plugin. I
need to find all the references in the
source using AST's or jdt.core.dom
or something like that. I need this
references like ASTNodes in order to
get the parent node and check several
things in the expression where
references are involved.
Thanks beforehand.
Edited:
I want to concrete a little more, My problem is that I try to catch some references to a constant but... I have not idea how I can do to catch in the matches this references. I need check the expressions which the references to a determined constant are involved. I only get the source of the method where they are used.
I think the problem is the scope or the pattern:
pattern = SearchPattern.createPattern(field, IJavaSearchConstants.REFERENCES);
scope = SearchEngine.createJavaSearchScope(declaringType.getMethods());
Thanks beforehand!
I used something like:
Search for the declaration of an
method, returns an IMethod
Search for references to the
IMethod, record those IMethods
For each IMethod returned, create an
AST from its compilation unit
Searching for declarations or references looks like the following code.
SearchRequestor findMethod = ...; // do something with the search results
SearchEngine engine = new SearchEngine();
IJavaSearchScope workspaceScope = SearchEngine.createWorkspaceScope();
SearchPattern pattern = SearchPattern.createPattern(searchString,
IJavaSearchConstants.METHOD, IJavaSearchConstants.DECLARATIONS,
SearchPattern.R_EXACT_MATCH);
SearchParticipant[] participant = new SearchParticipant[] { SearchEngine
.getDefaultSearchParticipant() };
engine.search(pattern, participant, workspaceScope, findMethod,
monitor);
Once you have your IMethod references, you can get to the AST using:
ASTParser parser = ASTParser.newParser(AST.JLS3);
parser.setResolveBindings(true);
if (methodToSearch.isBinary()) {
parser.setSource(methodToSearch.getClassFile());
} else {
parser.setSource(methodToSearch.getCompilationUnit());
}
CompilationUnit cu = (CompilationUnit) parser.createAST(null);
See http://help.eclipse.org/helios/index.jsp?topic=/org.eclipse.jdt.doc.isv/guide/jdt_int_core.htm for more details on java search, the java model, and the AST.
In all examples of F# classes and records I see that records an classes are instantiated/created via new keyword or simply by the type name.
So for example if I have this record:
type MyRecord = {field1: int; field2:int}
let myvar = {new MyRecord with field1 = 3 and field2 = 3}
let myvar2 = {MyRecord with field1 = 1 and field2 = 2}
let myvar3 = {field1 = 34; field2 = 23}
They seem to be all the same.
It is the same for this example too:
type MyClass(x: int) =
let mutable xx = x
let myvar = MyClass(12)
let myvar2 = new MyClassw(234)
Well what is new for?? Thnkyou
Ah... I know that there are answers for the question of new regarding classes, but there is no mention for records. Furthermore, I do not understand why new should be an optional and abosultely indifferent keywork when constructing classes? Is it possible that using new or not using it for classes does change nothing?
The new keyword is typically not used to instantiate F# records. The first example is the OCaml-ish syntax for record declarations:
let myvar = {new MyRecord with field1 = 3 and field2 = 3}
// Normal F#: let myvar = { MyRecord.field1 = 3; field2 = 3}
The second example doesn't compile any more:
// Not F#: let myvar2 = {MyRecord with field1 = 1 and field2 = 2}
For classes, you can always omit new. However, you get a compiler warning if you instantiate an IDisposable class without using the new keyword.
// These two are the same
let myvar = MyClass(12)
let myvar2 = new MyClass(234)
// Compiler warning
let f = FileStream("hello.txt", FileMode.Open)
// No warning
use f = new FileStream("hello.txt", FileMode.Open)
Edit: In response to your comment -
isn't there a rule or s rationale why new is so "flexible"? Why is it the same using or not using new for classes
new is optional - I'm not aware of a rationale for making it flexible; it would be nice if there was some guidance one way or the other. (My preference is to never use new, except in response to the compiler warning.)
why do I get a compiler warning when implementing IDisposable
Since I never use new normally, I take this to be the compiler's way of reminding me to write use or using when I allocate an IDisposable.
and why records do not use the second syntax I wrote before?
{ new MyRecord with ... } is the Haskell syntax. It may have been valid in one of the F# compiler betas, but it doesn't parse on F# 2.0. (Why do you think this ought to be valid?)
I'm trying to find a general logic rule/guideline rather than learning byheart a bunch or scattered syntax rules...
I know how you feel -- F# is a little like this, particularly when you come from a language like C#, where there's a right way and a wrong way to do something. My advice is to pick one of the alternatives and stick to it.
This may help: the F# Component Design guidelines [PDF] from Microsoft. It's a set of advice -- dos and don'ts -- for your F# code.
I could use some really good links that explain Generics and how to use them. But I also have a very specific question, relater to working on a current project.
Given this class constructor:
public class SecuredDomainViewModel<TDomainContext, TEntity> : DomainViewModel<TDomainContext, TEntity>
where TDomainContext : DomainContext, new()
where TEntity : Entity, new()
public SecuredDomainViewModel(TDomainContext domainContext, ProtectedItem protectedItem)
: base(domainContext)
{
this.protectedItem = protectedItem;
}
And its creation this way:
DomainViewModel d;
d = new SecuredDomainViewModel<MyContext, MyEntityType>(this.context, selectedProtectedItem);
Assuming I have 20 different EntityTypes within MyContext, is there any easier way to call the constructor without a large switch statement?
Also, since d is DomainViewModel and I later need to access methods from SecuredDomainViewModel, it seems I need to do this:
if (((SecuredDomainViewModel<MyContext, MyEntityType>)d).CanEditEntity)
But again "MyEntityType" could actually be one of 20 diffent types. Is there anyway to write these types of statements where MyEntityType is returned from some sort of Reflection?
Additional Info for Clarification:
I will investigate ConstructorInfo, but I think I may have incorrectly described what I'm looking to do.
Assume I have the DomainViewModel, d in my original posting.
This may have been constructed via three possible ways:
d = new SecuredDomainViewModel<MyContext, Order>(this.context, selectedProtectedItem);
d = new SecuredDomainViewModel<MyContext, Invoice>(this.context, selectedProtectedItem);
d = new SecuredDomainViewModel<MyContext, Consumer>(this.context, selectedProtectedItem);
Later, I need to access methods on the SecuredDomainViewModel, which currently must be called this way:
ex: if (((SecuredDomainViewModel<MyContext, Order)d).CanEditEntity)
ex: if (((SecuredDomainViewModel<MyContext, Invoice)d).CanEditEntity)
ex: if (((SecuredDomainViewModel<MyContext, Consumer)d).CanEditEntity)
Assuming I have N+ entity types in this context, what I was hoping to be able to do is
something like this with one call:
ex: if (((SecuredDomainViewModel<MyContext, CurrentEntityType)d).CanEditEntity)
Where CurrentEntityType was some sort of function or other type of call that returned Order, Invoice or Consumer based on the current item entity type.
Is that possible?
You can create a non-generic interface that has the CanEditEntity property on it, make SecuredDomainViewModel inherit off that, then call the property through the interface...
Also, the new() constructor allows you to call a constructor on a generic type that has no arguments (so you can just write new TEntity()), but if you want to call a constructor that has parameters one handy trick I use is to pass it in as a delegate:
public void Method<T>(Func<string, bool, T> ctor) {
// ...
T newobj = ctor("foo", true);
// ...
}
//called later...
Method((s, b) => new MyClass(s, b));
I can't help on the links, and likely not on the type either.
Constructor
If you have the Type, you can get the constructor:
ConstructorInfo construtor = typeof(MyEntityType).GetConstructor(new object[]{TDomainContext, ProtectedItem});
Type
I'm not really sure what you're looking for, but I can only see something like
if (((SecuredDomainViewModel<MyContext, entityType>)d).CanEditEntity)
{
entityType=typeof(Orders)
}
being what you want.
I have a very simple mapping function called "BuildEntity" that does the usual boring "left/right" coding required to dump my reader data into my domain object. (shown below) My question is this - If I don't bring back every column in this mapping as is, I get the "System.IndexOutOfRangeException" exception and wanted to know if ado.net had anything to correct this so I don't need to bring back every column with each call into SQL ...
What I'm really looking for is something like "IsValidColumn" so I can keep this 1 mapping function throughout my DataAccess class with all the left/right mappings defined - and have it work even when a sproc doesn't return every column listed ...
Using reader As SqlDataReader = cmd.ExecuteReader()
Dim product As Product
While reader.Read()
product = New Product()
product.ID = Convert.ToInt32(reader("ProductID"))
product.SupplierID = Convert.ToInt32(reader("SupplierID"))
product.CategoryID = Convert.ToInt32(reader("CategoryID"))
product.ProductName = Convert.ToString(reader("ProductName"))
product.QuantityPerUnit = Convert.ToString(reader("QuantityPerUnit"))
product.UnitPrice = Convert.ToDouble(reader("UnitPrice"))
product.UnitsInStock = Convert.ToInt32(reader("UnitsInStock"))
product.UnitsOnOrder = Convert.ToInt32(reader("UnitsOnOrder"))
product.ReorderLevel = Convert.ToInt32(reader("ReorderLevel"))
productList.Add(product)
End While
Also check out this extension method I wrote for use on data commands:
public static void Fill<T>(this IDbCommand cmd,
IList<T> list, Func<IDataReader, T> rowConverter)
{
using (var rdr = cmd.ExecuteReader())
{
while (rdr.Read())
{
list.Add(rowConverter(rdr));
}
}
}
You can use it like this:
cmd.Fill(products, r => r.GetProduct());
Where "products" is the IList<Product> you want to populate, and "GetProduct" contains the logic to create a Product instance from a data reader. It won't help with this specific problem of not having all the fields present, but if you're doing a lot of old-fashioned ADO.NET like this it can be quite handy.
Although connection.GetSchema("Tables") does return meta data about the tables in your database, it won't return everything in your sproc if you define any custom columns.
For example, if you throw in some random ad-hoc column like *SELECT ProductName,'Testing' As ProductTestName FROM dbo.Products" you won't see 'ProductTestName' as a column because it's not in the Schema of the Products table. To solve this, and ask for every column available in the returned data, leverage a method on the SqlDataReader object "GetSchemaTable()"
If I add this to the existing code sample you listed in your original question, you will notice just after the reader is declared I add a data table to capture the meta data from the reader itself. Next I loop through this meta data and add each column to another table that I use in the left-right code to check if each column exists.
Updated Source Code
Using reader As SqlDataReader = cmd.ExecuteReader()
Dim table As DataTable = reader.GetSchemaTable()
Dim colNames As New DataTable()
For Each row As DataRow In table.Rows
colNames.Columns.Add(row.ItemArray(0))
Next
Dim product As Product While reader.Read()
product = New Product()
If Not colNames.Columns("ProductID") Is Nothing Then
product.ID = Convert.ToInt32(reader("ProductID"))
End If
product.SupplierID = Convert.ToInt32(reader("SupplierID"))
product.CategoryID = Convert.ToInt32(reader("CategoryID"))
product.ProductName = Convert.ToString(reader("ProductName"))
product.QuantityPerUnit = Convert.ToString(reader("QuantityPerUnit"))
product.UnitPrice = Convert.ToDouble(reader("UnitPrice"))
product.UnitsInStock = Convert.ToInt32(reader("UnitsInStock"))
product.UnitsOnOrder = Convert.ToInt32(reader("UnitsOnOrder"))
product.ReorderLevel = Convert.ToInt32(reader("ReorderLevel"))
productList.Add(product)
End While
This is a hack to be honest, as you should return every column to hydrate your object correctly. But I thought to include this reader method as it would actually grab all the columns, even if they are not defined in your table schema.
This approach to mapping your relational data into your domain model might cause some issues when you get into a lazy loading scenario.
Why not just have each sproc return complete column set, using null, -1, or acceptable values where you don't have the data. Avoids having to catch IndexOutOfRangeException or re-writing everything in LinqToSql.
Use the GetSchemaTable() method to retrieve the metadata of the DataReader. The DataTable that is returned can be used to check if a specific column is present or not.
Why don't you use LinqToSql - everything you need is done automatically. For the sake of being general you can use any other ORM tool for .NET
If you don't want to use an ORM you can also use reflection for things like this (though in this case because ProductID is not named the same on both sides, you couldn't do it in the simplistic fashion demonstrated here):
List Provider in C#
I would call reader.GetOrdinal for each field name before starting the while loop. Unfortunately GetOrdinal throws an IndexOutOfRangeException if the field doesn't exist, so it won't be very performant.
You could probably store the results in a Dictionary<string, int> and use its ContainsKey method to determine if the field was supplied.
I ended up writing my own, but this mapper is pretty good (and simple): https://code.google.com/p/dapper-dot-net/