I am struggling on how to implement the following in the best way:
public abstract class Expr extends CFGNode {
...
}
public abstract class Stmt extends CFGNode {
...
}
public class CFGBuilder extends BaseVisitor<CFGNode> {
public CFGNode visitWhileStmt(#NotNull Parser.WhileStmtContext ctx) {
Expr nExpr = visit(ctx.expr()); => not working as it returns CFGNode
Stmt nStmt = visit(ctx.stmt()); => not working as it returns CFGNode
return new WhileStmt(nExpr, nStmt);
}
...
Option 1: Always return CFGNode, which contains 2 fields. Depending on the case, we use one of the two fields or both fields.
public abstract class CFGNode {
public Expr expr;
public Stmt stmt;
}
...
public CFGNode visitWhileStmt(#NotNull Parser.WhileStmtContext ctx) {
CFGNode nExpr = visit(ctx.expr());
CFGNode nStmt = visit(ctx.stmt());
return new WhileStmt(nExpr.expr, nStmt.stmt);
}
Option 2: Use casting
public abstract class CFGNode {
// No real fields
}
...
public CFGNode visitWhileStmt(#NotNull Parser.WhileStmtContext ctx) {
Expr nExpr = (Expr)(visit(ctx.expr());
Stmt nStmt = (Stmt)(visit(ctx.stmt());
return new WhileStmt(nExpr, nStmt);
}
Option 3: Use different visitors for each type that can be returned.
public class CFGBuilder extends BaseVisitor<Expr> {
...
public class CFGBuilder extends BaseVisitor<Stmt> {
...
Not very sure how this would work.
Option 4: Maybe there is an even better solution??
I would choose Option 2.
Option 1 means that CFGNode contains one field for every Type of AST node. And accessing these fields will produce a NullPointerException (where Option 2 would produce a ClassCastException) so there is no advantage over Option 2.
Option 3 will afford that you have a visitor for each AST node. And each visitor will mostly implement only one method.
Yet Option 2 will be not sufficient if the result is dependent on the context (a function call could be a statement or an expression, dependent on the result being used or discarded). In this case you will need to pass the expected type down the parse tree. Terrence Parr explains solutions for that in 'The Definitive ANTLR4 Reference'
use the java call stack (would be Option 2)
maintain a separate stack (allows to pass information down the parse tree, by pushing it on the stack)
annotate the parse tree (maintain a map of parse tree nodes to attributes, see ParseTreeProperty<T>)
Related
I have a Spring MVC survey application where the Controller method called by each form POST is virtually identical:
#PostMapping("/1")
public String processGroupOne (
Model model,
#ModelAttribute("pageNum") int pageNum,
#ModelAttribute(GlobalControllerAdvice.SESSION_ATTRIBUTE_NAME) #Validated(SurveyGroupOne.class) SurveyCommand surveyCommand,
BindingResult result) {
if (result.hasErrors()) {
LOG.debug(result.getAllErrors().toString());
model.addAttribute("pageNum", pageNum);
return "survey/page".concat(Integer.toString(pageNum));
}
pageNum++;
model.addAttribute("pageNum", pageNum);
return "redirect:/survey/".concat(Integer.toString(pageNum));
}
The only difference is what part of the SurveyCommand object is validated at each stop along the way. This is designated by the marker interface passed to the #Validated() annotation. The marker interfaces (SurveyGroupOne, SurveyGroupTwo, etc) are just that, markers:
public interface SurveyGroupOne {}
public interface SurveyGroupTwo {}
...
and they are applied to properties of objects in the SurveyCommand object:
public class Person {
#NotBlank(groups = {
SurveyGroupTwo.class,
SurveyGroupThree.class})
private String firstName;
#NotBlank(groups = {
SurveyGroupTwo.class,
SurveyGroupThree.class})
private String lastName;
...
}
My question: how can I make the method generic and still use the marker interface specific to the page being processed? Something like this:
#PostMapping("/{pageNum}")
public String processGroupOne (
Model model,
#PathVariable("pageNum") int pageNum,
#ModelAttribute(GlobalControllerAdvice.SESSION_ATTRIBUTE_NAME)
#Validated(__what goes here??__) SurveyCommand surveyCommand,
BindingResult result) {
if (result.hasErrors()) {
LOG.debug(result.getAllErrors().toString());
model.addAttribute("pageNum", pageNum);
return "survey/page".concat(Integer.toString(pageNum));
}
pageNum++;
model.addAttribute("pageNum", pageNum);
return "redirect:/survey/".concat(Integer.toString(pageNum));
}
How can I pass the proper marker interface to #Validated based solely on the pageNum #PathVariable (or any other parameter)?
Because #Validated is an annotation, it requires its arguments to be available during compilation and hence static. You can still use it but in this case you will have N methods, where N is a number of steps. To distinguish one step from another you can use params argument of #PostMapping annotation.
There is also another way where you need to inject Validator to the controller and invoke it directly with an appropriate group that you need.
Given an Activity (created via the designer) that has several OutArgument properties, is it possible to get their strongly-typed value from a property after invoking the workflow?
The code looks like this:
// generated class
public partial class ActivityFoo : System.Activities.Activity....
{
....
public System.Activities.OutArgument<decimal> Bar { ... }
public System.Activities.OutArgument<string> Baz { ... }
}
// my class
var activity = new ActivityFoo();
var result = WorkflowInvoker.Invoke(activity);
decimal d = activity.Bar.Get(?)
string s = activity.Baz.Get(?)
The T Get() method on OutArgument<T> that requires an ActivityContext which I'm not sure how to obtain in code.
I also realize it's possible to get the un-typed values from result["Bar"] and result["Baz"] and cast them, but I'm hoping there's another way.
Updated to make it clear there are multiple Out values, although the question would still apply even if there was only one.
If you look at workflows as code, an Activity is no more than a method that receives input arguments and (potentially) returns output arguments.
It happens that Activities allows one to return multiple output arguments, something that C# methods, for example, don't (actually that's about to change with C# 7 and tuples).
That's why you've an WorkflowInvoker.Invoke() overload which returns a Dictionary<string, object> because the framework obviously doesn't know what\how many\of what type output arguments you have.
Bottom line, the only way for you to do it fully strong-typed is exactly the same way you would be doing on a normal C# method - return one OutArgument of a custom type:
public class ActivityFooOutput
{
public decimal Bar { get; set }
public decimal Baz { get; set; }
}
// generated class
public partial class ActivityFoo : System.Activities.Activity....
{
public System.Activities.OutArgument<ActivityFooOutput> Result { ... }
}
// everything's strongly-typed from here on
var result = WorkflowInvoker.Invoke<ActivityFooOutput>(activity);
decimal d = result.Bar;
string s result.Baz;
Actually, if you don't want to create a custom type for it, you can use said tuples:
// generated
public System.Activities.OutArgument<Tuple<decimal, string>> Result { ... }
// everything's strongly-typed from here on
var result = WorkflowInvoker.Invoke<Tuple<decimal, string>>(activity);
decimal d = result.Item1;
string s result.Item2;
Being the first option obviously more scalable and verbose.
I'm looking for a way in java to find all classes that belongs to a certain superclass, and within that class refer to a static string with a known name (using reflection?);
public class Bar
extends ObjectInstance
{
public final static String Name = "Foo";
// more
}
From the example; there are n-occurences of classes that extend from ObjectInstance, and from all, i need the value of Name. The classes i am refering to are generated so i know for sure that there is a Name element that i can refer to, but i have no access to the generation sourcedata.
Perhaps the same question as How do you find all subclasses of a given class in Java?
This backs up my initial feeling that this can only be done like IDEs do it: by scanning everything down the tree, building your relationships as you go.
No Way.
One failing solution:
publc abstract class ObjectInstance {
public abstring String name();
private static Map<String, Class<? extends ObjectInstance> klasses =
new HashMap<>();
protected ObjectInstance() {
classes.put(name(), getClass());
}
Only collects instantiated classes! So fails.
With the idea to have the name provided by a function with return "foo";.
Collecting the class.
There are two unsatisfactory solutions:
The other way around: use the name as a factory pattern:
enum Name {
FOO(Bar.class),
BAZ(Baz.class),
QUX(Qux.class),
BAR(Foo.class);
public final Class<ObjectInstance> klass;
private Name(Class<ObjectInstance> klass) {
this.klass = klass;
}
}
Maybe as factory to create instances too.
Using a class annotation, and have a compile time scanning:
#ObjectInstanceName("foo")
public class Bar extends ObjectInstance {
}
How to apply this to your case: experiment.
There would be a more fitting solution of using your own ClassLoader, but that is far too over-engineered.
I am trying to run a parametrized tests... Was trying to implement it like it explained here:
http://docs.flexunit.org/index.php?title=Parameterized_Test_Styles
Here is what my test case looking
import org.flexunit.runners.Parameterized;
[RunWith("org.flexunit.runners.Parameterized")]
public class ArrayBasedStackTests
{
[Paremeters]
public static var stackProvider:Array = [new ArrayBasedStack(), new LinkedListBasedStack()] ;
private var _stack:IStack;
public function ArrayBasedStackTests(param:IStack)
{
_stack = param;
}
[Before]
public function setUp():void
{
}
[After]
public function tearDown():void
{
}
[Test ( description = "Checks isEmpty method of the stack. For empty stack", dataProvider="stackProvider" )]
public function isEmptyStackPositiveTest():void
{
var stack:IStack = _stack;
assertEquals( true, stack.isEmpty() );
}
But this code throws following initializing Error:
Error: Custom runner class org.flexunit.runners.Parameterized should
be linked into project and implement IRunner. Further it needs to have
a constructor which either just accepts the class, or the class and a
builder.
Need help to fix it
UPDATE
I've updated the code so it looks like this
[RunWith("org.flexunit.runners.Parameterized")]
public class ArrayBasedStackTests
{
private var foo:Parameterized;
[Parameters]
public static function stacks():Array
{
return [ [new ArrayBasedStack()], [new LinkedListBasedStack()] ] ;
}
[Before]
public function setUp():void
{
}
[After]
public function tearDown():void
{
}
[Test ( description = "Checks isEmpty method of the stack. For empty stack", dataProvider="stacks")]
public function isEmptyStackPositiveTest(stack:IStack):void
{
assertEquals( true, _stack.isEmpty() );
}
It works. But the result is a bit strange. I have 4 test executed instead of 2. (I have 2 items in data provider, so cant get why do I have 4 tests).
Output
http://screencast.com/t/G8DHbcjDUkJ
The [Parameters] meta-data specifies that the parameters are passed to the constructor of the test - so the test class is called for each parameter. You also have the dataProvider set for the specific test method, so the test method is also called once for each parameter. Two calls for the test, and two calls to the method, ends up running four tests.
The solution is to either use [Parameters] meta-tag which specifies the data to use for the whole test class, or use the dataProvider for each test method, but not both with the same data at the same time.
You're missing the static reference to Paramaterized, as shown here:
import org.flexunit.runners.Parameterized;
[RunWith("org.flexunit.runners.Parameterized")]
public class MyTestNGTest
{
private var foo:Parameterized;
...
Basically, that error means that the [Runner] defined isn't available at runtime, which occurs if there is no static reference in the class to cause it to get linked in.
In FlexUnit 4.5.1, this approach changed to using [Rule]'s like so:
public class MyTestNGTest
{
[Rule]
public function paramaterizedRule:ParamaterizedRule = new ParamaterizedRule();
...
}
However, I can't seem to see an actual implementation of IMethodRule for paramaterized tests (that example is fictional).
I am modifiying a class method which formats some input paramater dates which are subsequently used as params in a method call into the base class (which lives in another assembly).
I want to verify that the dates i pass in to my method are in the correct format when they are passed to the base class method so i would like to Moq the base class method call. Is this possible with Moq?
As of 2013 with latest Moq you can. Here is an example
public class ViewModelBase
{
public virtual bool IsValid(DateTime date)
{
//some complex shared stuff here
}
}
public class MyViewModel : ViewModelBase
{
public void Save(DateTime date)
{
if (IsValid(date))
{
//do something here
}
}
}
public void MyTest()
{
//arrange
var mockMyViewModel = new Mock<MyViewModel>(){CallBase = true};
mockMyViewModel.Setup(x => x.IsValid(It.IsAny<DateTime>())).Returns(true);
//act
mockMyViewModel.Object.Save();
//assert
//do your assertions here
}
If I understand your question correctly, you have a class A defined in some other assembly, and then an class B implemented more or less like this:
public class B : A
{
public override MyMethod(object input)
{
// Do something
base.MyMethod(input);
}
}
And now you want to verify that base.MyMethod is called?
I don't see how you can do this with a dynamic mock library. All dynamic mock libraries (with the exception of TypeMock) work by dynamically emitting classes that derive from the type in question.
In your case, you can't very well ask Moq to derive from A, since you want to test B.
This means that you must ask Moq to give you a Mock<B>. However, this means that the emitted type derives from B, and while it can override MyMethod (which is still virtual) and call its base (B.MyMethod), it has no way of getting to the original class and verify that B calls base.MyMethod.
Imagine that you have to write a class (C) that derives from B. While you can override MyMethod, there's no way you can verify that B calls A:
public class C : B
{
public override MyMethod(object input)
{
// How to verify that base calls its base?
// base in this context means B, not A
}
}
Again with the possible exception of TypeMock, dynamic mock libraries cannot do anything that you cannot do manually.
However, I would assume that calling the base method you are trying to verify has some observable side effect, so if possible, can you use state-based testing instead of behaviour-based testing to verify the outcome of calling the method?
In any case, state-based testing ought to be your default approach in most cases.
Agree with Mark, it's not possible using Moq.
Depending on your situation you may consider swithcing from inheritance to composition. Then you'll be able to mock the dependency and verify your method. Of course in some cases it just might not worth it.
wrap the base class method in a method and setup that method
e.g.
public class B : A
{
public virtual BaseMyMethod(object input)
{
// Do something
base.MyMethod(input);
}
public override MyMethod(object input)
{
// Do something
BaseMyMethod(input);
}
}
and now Setup the BaseMyMethod
It is quite possible mocking base class. But you will have to modify target class.
For ex. DerivedClass extends BaseClass.
BaseClass has methods MethodA(), MethodB(), MethodC()...
The DerivedClass has this method:
void MyMethod() {
this.MethodA();
this.MethodB();
this.MethodC();
}
You want to mock base class in order to validate that all MethodA(), MethodB(), MethodC() are being called inside MyMethod().
You have to create a field in the DerivedClass:
class DerivedClass {
private BaseClass self = this;
...
}
And also You have to modify the MyMethod():
void MyMethod() {
self.MethodA();
self.MethodB();
self.MethodC();
}
Also add a method, which can inject the this.self field with Mock object
public void setMock(BaseClass mock) {
this.self = mock;
}
Now you can mock:
DerivedClass target = new DerivedClass ();
BaseClass mock = new Mock(typeof(BaseClass));
target.setMock(mock);
target.MyMethod();
mock.verify(MethodA);
mock.verify(MethodB);
mock.verify(MethodC);
Using this technic, you can also mock nested method calls.
I found this solution - ugly but it could work.
var real = new SubCoreClass();
var mock = new Mock<SubCoreClass>();
mock.CallBase = true;
var obj = mock.Object;
mock
.Setup(c => c.Execute())
.Callback(() =>
{
obj.CallBaseMember(typeof(Action), real, "Execute");
Console.WriteLine(obj.GetHashCode());
}
);
public static Delegate CreateBaseCallDelegate(object injectedInstance, Type templateDelegate, object instanceOfBase, string methodName)
{
var deleg = Delegate.CreateDelegate(templateDelegate, instanceOfBase, methodName);
deleg.GetType().BaseType.BaseType.GetField("_target", BindingFlags.Instance | BindingFlags.NonPublic).SetValue(deleg, injectedInstance);
return deleg;
}
public static object CallBaseMember(this object injectedInstance, Type templateDelegate, object instanceOfBase, string methodName, params object[] arguments)
{
return CreateBaseCallDelegate(injectedInstance, templateDelegate, instanceOfBase, methodName).DynamicInvoke(arguments);
}