I only recently completed a unit on software patterns and am now attempting to comprehend the PureMVC framework. One thing has got my stumped however, something which is simple to the gurus here.
I'm attempting to create an instance of the singleton Facade class. In the constructor, the comments state:
This IFacade implementation is a Singleton, so you should not call the constructor directly, but instead call the static Singleton Factory method Facade.Instance
How can you call the instance method when the Facade object has not even been created?
The Facade.Instance method looks like this:
public static IFacade Instance
{
get
{
if (m_instance == null)
{
lock (m_staticSyncRoot)
{
if (m_instance == null) m_instance = new Facade();
}
}
return m_instance;
}
}
You are accessing a static property. Static properties are part of the class definition, not class instances. To access a static member (property, field, method), simply use the class name dot member:
var myFacade = SomeClass.Instance;
Related
I'd like you ask a few questions and ask you for advice:
I want to test my public method (I use Spring Boot, Mockito, JUnit):
#Service
public class MyClass{
public Long getClientId(List<String> nameSurname) throws AuthorizationException {
Long operatorId;
if(...){
(... something not interesting ...)
User user = getUserByLogin("AnthonyGates2");
operatorId = nonNull(user) ? user.getOperatorId() : null;
} else {
List<User> users = getUserListByLogin("AnthinyGates");
operatorId = isNotEmpty(users) ? return operatorId;
return operatorId;
}
How to test the method getClientId?
Methods getUserByLogin and getUserListByLogin are private in this class (MyClass) but I have to mock the results of these private methods because these methods retrieve data from an external service.
These private methods looks like:
User user = DelegateImpl.getDelegate().getUserByLogin(nameAndSurname);
DelegateImpl.getDelegate().getUserByLogin get data from database and that data have to be mocked like:
when(DelegateImpl.getDelegate().getUserByLogin(any())).thenReturn(user);
How can I test my public class? Should I use PowerMock/PowerMockito? Making these methods public is in my opinion ugly because these methods are called only in MyClass. I can't find a good tutorial in Internet for my case (Spring Boot, Mockito, JUnit).
Thank you very much for all your tips!
Best regards
Matthew
Test the unit only by calling the public methods. I think that your example is a class in the service layer (contains business logic) and the two getUser... methods should be in a different class (I think in the data layer) where they can be public. Inject that class via the constructor as a dependency (in the service object) so you can mock it when testing the service class. The data layer class (with the getUser... methods) can also be tested by it's own unit tests.
If you are not able to unit test a method/class then it most probably means that it just does too much. Try extracting your private methods to a separate class. It does not need to be public - you can e.g. have it package-local in the same package.
Later, in the test, you would have to inject a mock of this class and simulate its behaviour.
The setup of MyClass in its unit test could look similar to this:
AnotherClass anotherClassMock = Mockito.mock(AnotherClass.class);
MyClass myClass = new MyClass(anotherClassMock);
Where AnotherClass would have methods getUserListByLogin and getUserByLogin.
EDIT:
It seems that the logic within in your private methods already call an external class. The problem is that you obtain an instance of an object via a call to a static getDelegate() method in another class.
Here's what you can do:
Create a new field in MyClass which would have the same type as the one returned by getDelegate() method (I don't know what that is, I'll call it Delegate)
Have 2 constructors: a default one which would assign the result of getDelegate method to your new field and another one which would take an instance of Delegate as a parameter and assign it to your field
In tests use the second constructor to create an instance of MyClass and pass a mock of Delegate class
It would look more ore less like this:
class MyClass() {
private Delegate delegate;
MyClass() {
this.delegate = DelegateImpl.getDelegate();
}
MyClass(Delegate delegate) {
this.delegate = delegate;
}
// ... the rest
}
I am a little confused about these types.
Especially XXXDelegate_Extention classes. If I want to implement an optional protocol method, will this XXXDelegate_Extention be useful? Or I always need to subclass the XXXDelegate class?
Thanks!
Delegates on iOS can have optional methods. Since the interface IXXDelegate only declares the non-optional functions, XXXDelegate only implements the non-optional functions. The XXXDelegate_Extention adds the optional functionsto the delegate (interface). So you can either inherit from XXXDelegate or implement IXXXDelegate completely on your own. I'd prefer inheriting, unless you really need to have a totally custom implementation.
Extension methods in C# are methods, that can be called like instance methods, but are not declared within the type of this instance.
Example on Extension methods
public class MyClass
{
public int Foo(int a)
{
return a + 1;
}
}
public static class MyClassExtension
{
public static int Bar(this MyClass my, int a)
{
return my.Foo(a+1);
}
}
var x = new MyClass();
x.Foo(2); // returns 3
x.Bar(2); // returns 4
More info: https://msdn.microsoft.com/en-us//library/bb383977.aspx
I have a code that looks like this
public class EmployeeController : Controller
{
public ContextWrapper contextWrapper;
public EmployeeController (IContextWrapper wrapper)
{
contextWrapper = wrapper;
}
In my dependency resolver I have the binding for IContextWrapper
kernel.Bind<IContextWrapper>().To<ContextWrapper>();
The implementation of ContextWrapper has an object which is of type Linq DataContext.
public class ContextWrapper : IContextWrapper
{
public MyDataContext dataContext;
public ContextWrapper(MyDataContext context)
{
this.dataContext = context;
}
Now my action method in this controller looks like this
var empRepository = new EmployeeRepository(contextWrapper);
//do some tests with this repository.
some values = contextWrapper.datacontext.get some values from the database table
//do some tests with these values.
To be able to test this method
I should be able to provide some sort of mock database(not literally) or
make the contextWrapper.datacontext return mocked values or
I even thought of creating another implementation of the IContextWrapper that doesn't use a Linq DataContext object. And creating another constructor for this controller and pass that fake implementation. Also in my dependency resolver I would bind the fake object to the IContextWrapper. Although I do not know how to make Ninject
As a last resort test my method against a test database since it all boils down to this Linq DataContext object and it seems I cannot get rid of it past a certain level.
Problem is the more I read about it, more I get confused. I have tried to give as much detail as possible to explain my problem. If any one has a clear cut idea about how to get this, please suggest.
Hey this is a very simple question. Can I call a variable, in this case an array, from a void method? I have declared my arrays at the class level and initialized them in a void method. Not sure it I am doing this correctly but I am trying to call the array from another class. I am a beginner. Thank you for the help.
ex:
public class HeyThere{
public double me[];
public void yeahYou(int you){
me = new me[69]
}
}
Here you declarate a public variable (array)
public double me[ ];
and here you instantiate it in a method
me = new me[69]
Yes, since your class level array me is scoped as Public, you will be able to access it from another class after you instantiate the HeyThere class.
Ex:
public class HeyThereCaller
{
..
....
public void SomeMethod()
{
...
....
HeyThere heyThereInstance = new HeyThere();
double[] meArray = heyThereInstance.me;
}
}
HeyThere obj1; double a = obj1.me[0]; This is going to give an error in Java though, because me is not instantiated
Yes, you certainly can! Because me is public, you can access it from outside of the class in which it is stored.
Also, you spoke of accessing it from a void method. The return type of a method has no effect on the data it can access; void only means that the method doesn't return a value when called.
If you want to study how variables can be accessed in Java, there is some useful info on this page.
From my controller I would like to dynamically select a service based on a parameter.
Currently I have a base service and some other services that extent this base service. Based on the parameter I call a class that does creates a bean name based on the param and eventually calls the following:
import org.codehaus.groovy.grails.web.context.ServletContextHolder as SCH
import org.codehaus.groovy.grails.web.servlet.GrailsApplicationAttributes as GA
class Resolver {
def ctx
def getBean(String beanName) {
if(!ctx) {
ctx = SCH.servletContext.getAttribute(GA.APPLICATION_CONTEXT)
}
return ctx."${beanName}"
}
}
This returns the service I want. However I feel rather dirty doing it this way. Does anyone have a better way to handle getting a service (or any other bean) based on some parameter?
Thank you.
ctx."${beanName}" is added to the ApplicationContext metaclass so you can do stuff like def userService = ctx.userService. It's just a shortcut for ctx.getBean('userService') so you could change your code to
return ctx.getBean(beanName)
and it would be the same, but less magical.
Since you're calling this from a controller or a service, I'd skip the ServletContextHolder stuff and get the context by dependency-injecting the grailsApplication bean (def grailsApplication) and getting it via def ctx = grailsApplication.mainContext. Then pass it into this helper class (remember the big paradigm of Spring is dependency injection, not old-school dependency-pulling) and then it would be simply
class Resolver {
def getBean(ctx, String beanName) {
ctx.getBean(beanName)
}
}
But then it's so simple that I wouldn't bother with the helper class at all :)