I have the following code.
public void GetMessages(Expression<Func<IMessageQueryable, bool>> messageSpecification, string folder = "INBOX")
{
// Implementation stripped
}
How can i provide default value for messageSpecification?. Specification says the value must be a compile time constant. Is this possible?.
EDIT: Not lookig for specifying it as Expression<Func<IMessageQueryable, bool>> messageSpecification = null
You can OverLoad it. What would your default value be?
Why bother? Create an overload for the same method without messageSpecification parameter and define it's default value yourself inside the overloaded method and pass it to your original method. Default parameters are actually never meant to be used like that anyway.
public void GetMessages(string folder = "INBOX")
{
this.GetMessages(DEFAULT_VALUE, folder);
}
Related
The setters with the int values say int cannot be dereferenced, and string value cannot find the method. I may not understand completely, but they look fine to me.
Please advise, thank you!
private void setMachineID(int machineID) {
machineID.set(machineID);
}
public int getMachineID(){
return machineID.get();
}
public IntegerProperty machineIDProperty(){
return machineID;
}
}
You're using the same identifier for the fields and the method parameters.
If there are more than 1 variable with the same identifier visible in a part of the code, java will use the one that is declared "closer" to this part of the code.
In this case the scope of the method parameter is the method which is "closer" to the method body than the fields. For this reason you must tell java explicitly that you want to use the field, not the method parameter.
You need to add change your setters like this:
Before
private void setMachineID(int machineID) {
machineID.set(machineID);
// ^^^^^^^^^ references method parameter
// ^^^^^^^^^ references method parameter
}
After
private void setMachineID(int machineID) {
this.machineID.set(machineID);
// ^^^^^^^^^^^^^^ References field
// ^^^^^^^^^ references method parameter
}
I want to be sure that mocked is called with specific set of strings as parameter.
For example, I have the following code:
public class SomeLogic {
#Autowired
private SpecificService specificService;
public void action() {
Set<String> args = fillArgsMethod();
specificService.handleArgs(args);
}
}
And my current try to test it is the following
#Mock
private SpecificService specificService
#InjectMocks
private SomeLogic someLogic;
#Test
public void testAction() {
someLogic.action();
verify(specificService).handleArgs(anySet());
}
But I want to be sure, that handleArgs() will receive the exact set of strings, that I expect. How can I modify verifying to check that handleArgs is called with set "first","second"?
Thanks
Isah gave a valid answer, but I want to turn your attention to a more general feature of Mockito which is ArgumentCaptor
In you case you would do something along the following lines:
Class<HashSet<String>> setClass = (Class<HashSet<String>>)(Class)HashSet.class;
ArgumentCaptor<Set<String>> setCaptor= ArgumentCaptor.forClass(setClass .class);
verify(specificService).create(setCaptor.capture());
HashSet<String> capturedSet = setCaptor.getValue();
//do whatever test you want with capturedSet
Prepare your Set parameters before calling the test method
#Test
public void testAction() {
Set<String> expectedParams = new HashSet(Arrays.asList("first", "second");
//call tested method
verify(specificService).handleArgs(expectedParams);
}
isah's solution is perfect for you if you want to confirm that the set contains exactly the two items you specify; Mockito compares using .equals by default, and Set.equals is defined as refer to equal elements in any order.
For a more-flexible "contains" test that matches your question title, that allows for set members beyond your expected values, you can also use the Hamcrest contains matcher:
someLogic.action();
verify(specificService).handleArgs(argThat(contains("first", "second")));
At least, that's how it should look. Unfortunately, argThat infers its return type from the Matcher, which infers its return type from the arguments, so Java assumes your first argument is not a Set<String> but a Iterable<capture#1-of ? extends String>. You'll need to cast explicitly and suppress warnings to get it to work:
// requires #SuppressWarnings("unchecked")
verify(specificService).handleArgs(
(Set<String>) argThat(contains("first", "second")));
I have the following method:
public void SetList<T>(IList<T> listINeedToStore)
{
//Store the list in instance level scope
}
I would like to take the listINeedToStore parameter and store it in a private variable but I have failed to find a way. I tried to do something like private IList<object> _tempVariable; and then set _tempVariable to the listINeedToStore variable so I can use it later to remove or add items to it. I would set the list like _tempVariable = (IList<object>)listINeedToStore;. This does not work and will not compile. Something I should note is that T is a type of Enum.
I am sure there is a way to do this but I do not know it.
Thanks,
You can't do it in a generic way without making the type generic instead of the method, basically. You can store the reference, but it would have to be via a field of a non-generic type, e.g. IEnumerable or even just object. To really use the list, you'd have to fetch it again with a generic method, and cast. For example:
private object list;
public void SetList<T>(IList<T> list)
{
this.list = list;
}
public List<T> GetList<T>()
{
return (List<T>) list;
}
The fetch will fail at execution time if you specify the wrong type argument, of course.
I'd try to avoid this design if possible, but if you really need to do it, it will work. It just adds the burden of getting the type right to all the callers.
Note that if you change the parameter from IList<T> to List<T>, you could then store it in an IList (non-generic) which could be slightly more useful - but which would restrict the circumstances in which you could call the method, of course.
Suppose I have a List<IMyInterface>...
I have three classes which implement IMyInterface: MyClass1, MyClass2, and MyClass3
I have a readonly Dictionary:
private static readonly Dictionary<Type, Type> DeclarationTypes = new Dictionary<Type, Type>
{
{ typeof(MyClass1), typeof(FunnyClass1) },
{ typeof(MyClass2), typeof(FunnyClass2) },
{ typeof(MyClass3), typeof(FunnyClass3) },
};
I have another interface, IFunnyInteface<T> where T : IMyInterface
I have a method:
public static IFunnyInterface<T> ConvertToFunnyClass<T>(this T node) where T : IMyInterface
{
if (DeclarationTypes.ContainsKey(node.GetType())) {
IFunnyInterface<T> otherClassInstance = (FunnyInterface<T>) Activator.CreateInstance(DeclarationTypes[node.GetType()], node);
return otherClassInstance;
}
return null;
}
I'm trying to call the constructor of FunnyClasses and insert as parameter my MyClass object. I don't want to know which object it is: I just want to instantiate some FunnyClass with MyClass as a parameter.
What happens when I call ConvertToFunnyClass, T is of type IMyInterface, and when I try to cast it to FunnyInterface<T>, it says I can't convert FunnyClass1, for instance, to FunnyInterface<IMyInterface>
My current workaround (not a beautiful one), is this:
public static dynamic ConvertToFunnyClass<T>(this T node) where T : IMyInterface
{
if (DeclarationTypes.ContainsKey(node.GetType())) {
var otherClassInstance = (FunnyInterface<T>) Activator.CreateInstance(DeclarationTypes[node.GetType()], node);
return otherClassInstance;
}
return null;
}
And I don't like it because the return type is dynamic, so when I access it from somewhere else, I have no idea what type it is, and I lose intellisense, and stuff. I don't know about any performance implications either.
Any clues?
Thanks in Advance!
Resolution
As I'm using C# 4.0, I could stop casting errors using covariance (output positions only), and so I changed my IFunnyInterface to
IFunnyInteface<out T> where T : IMyInterface
Thank you all for the replies.
Essentially, your problem is that you are trying to convert FunnyInterface<T> to FunnyInterface<IMyInterface>. As has been mentioned several times (one example is here, more information here), this is not valid in most circumstances. Only in .NET 4, when the generic type is an interface or delegate, and the type parameter has been explicitly declared as variant with in or out, can you perform this conversion.
Is FunnyInterface actually an interface?
thecoop answer points you exactly to why you can't do it.
A cleaner solution to the problem (besides using dynamic) would be a base non-Generics Interface:
public interface IFunnyInterfaceBase
{
}
public interface IFunnyInteface<T> : IFunnyInterfaceBase
where T : IMyInterface
{
}
And you need to move methods signature you use in that code from IFunnyInteface to IFunnyInterfaceBase.
This way you would be able to write something like this:
MyClass2 c2 = new MyClass2();
IFunnyInterfaceBase funnyInstance = c2.ConvertToFunnyClass();
The Exception you said you got in your code is not due to the extension method signature itself (the method is fine)..it is originated by the type of your lvalue (the type of the variable you use to store its return value)!
Obviously this solution applies only if you can modify IFunnyInterface source code!
There are a lot of workarounds for the missing support of enumerations in the Entity Framework 4.0. From all of them I like this one at most:
http://blogs.msdn.com/b/alexj/archive/2009/06/05/tip-23-how-to-fake-enums-in-ef-4.aspx?PageIndex=2#comments
This workaround allows you to use enums in your LINQ queries which is what i exactly need. However, I have a problem with this workaround. I get for every complex type I'm using a new partial autogenerated class.Therefore the code does not compile any more because I already have a wrapper class with this name in the same namespace which converts betwen the backed integer in the database and the enum in my POCO classes. If I make my wrapper a partial class, the code still does not compile as it now contains two properties with the same name "Value". The only possibility is to remove the Value property by hand everytime I generate the POCO classes because the DB model changed (which during the development phase happens very often).
Do you know how to prevent a partial class to be generated out of complex property everytime the EF model changes?
Can you recommend me some other workarounds supporting enumerations in LINQ queries?
That workaround is based on the fact that you are writing your POCO classes yourselves = no autogeneration. If you want to use it with autogeneration you must heavily modify T4 template itself.
Other workaround is wrapping enum conversion to custom extension methods.
public static IQueryable<MyEntity> FilterByMyEnum(this IQueryable<MyEntity> query, MyEnum enumValue)
{
int val = (int)enumValue;
return query.Where(e => e.MyEnumValue == val);
}
You will then call just:
var data = context.MyEntitites.FilterByMyEnum(MyEnum.SomeValue).ToList();
I am using an approach based on the one described in your link without any modifications of the T4 templates. The contents of my partial wrapper classes are as follows:
public partial class PriorityWrapper
{
public Priority EnumValue
{
get
{
return (Priority)Value;
}
set
{
Value = (int)value;
}
}
public static implicit operator PriorityWrapper(Priority value)
{
return new PriorityWrapper { EnumValue = value };
}
public static implicit operator Priority(PriorityWrapper value)
{
if (value == null)
return Priority.High;
else
return value.EnumValue;
}
}
I've only changed that instead of a back store variable with enum value I am using the autogenerated int typed Value property. Consequently Value can be an auto-implemented property and EnumValue property needs to do the conversion in getter and setter methods.