How do i declare a static generator method in ES6 class ?
class Person
{
static *getData(){
}
}
Build when no export of the class is specified
This is actually a problem with flow type.
static* getData<T>(): Iterable<T> {}
Try with this form.
Related
I would like to use a statically imported method in code generated with Xtend's active annotations. As an example, I want to get this output:
import static java.util.Collections.emptyList;
#MyActiveAnnotation
public class MyTest {
public void foo() {
emptyList();
}
}
My compilation participant looks like this:
override doTransform(MutableClassDeclaration clazz, extension TransformationContext context) {
clazz.addMethod("foo", [
body = '''
«Collections».emptyList();
])
While this code works and imports Collections, it doesn't statically import the emptyList method.
How can I statically import methods using Xtend's active annotations?
According to Xtend developers, this doesn't seem possible.
just like in the topic. I have my resource class :
public class HelloWorldEndpoint implements IRest {
public String sayHello()
{
return "Hello world!";
}
}
And Interface :
#Path("/helloworld")
public interface IRest {
#GET
#Path("/hello")
String sayHello();
}
Is it possible to match sayHello() from HelloWorldEndpoint using only #Path class annotation? This is very specific example of resource class implementation, but it shows that it is possible to have REST endpoint without any annotation in class.. I've tried with inheritsAnnotation() and isAnnotatedWith() but it's not working that way unfortunatly. My goal is to find all resource classes :)
Annotations of interfaces are not inherited in accordance to the Java Langauge specification. They are neither exposed by the reflection API, for example.
In order to discover the annotation, you can manually travers the class hierarchy and look for the annotation in question. This is possible by hasSuperType(isAnnotatedWith(...)). Note that this is a rather expensive matching condition.
In my application I'll need to create a functions library to be accessed from different components. What is the best way to do this? Do I need to make a service with all the functions or a class or a module or a component?
In this library if I call a function from a component and this function need to access a variable in the caller, will it be possible to do?
If it's just a set of one off helper functions the easiest way is create an #Injectable service with your helper methods then inject that into any component that requires them. You can provide public vars as well so they're accessible in your html.
#Injectable()
export class Helpers {
helper1() { return "hello"; }
helper2(x) { return x + 1 }
}
#Component({
providers: [Helpers],
template: "<div>{{helper1()}}</div>" // will display 'hello'
)}
export class MyComponent {
public helper1: Function = Helpers.helper1;
constructor() {
console.log(Helpers.helper2(5)); // will output '6'
}
}
This works great for a simple set of random utility functions. If you need something more in depth please explain and we can provide alternate solutions.
Most of my components are registered using the code-based (fluent) approach, but there is one particular component that I need to resolve differently at runtime. This is the interface and a couple of concrete implementations:-
public interface ICommsService ...
public class SerialCommsService : ICommsService ...
public class TcpCommsService : ICommsService ...
Some of our users will need the serial service while others will need the TCP service. My current solution (which works btw) is to use a typed factory and a custom component selector - the latter reads an app.config setting to determine which implementation the typed factory will resolve and return.
First the typed factory (nothing special about this):-
public interface ICommsServiceFactory
{
ICommsService Create();
void Release(ICommsService component);
}
Next, the custom component selector, which reads the fully-qualified type name from app.config (e.g. "MyApp.SomeNamespace.TcpCommsService"):-
public class CommsFactoryComponentSelector : DefaultTypedFactoryComponentSelector
{
protected override string GetComponentName(MethodInfo method, object[] arguments)
{
return ConfigurationManager.AppSettings["commsServiceType"];
}
}
Then the registration stuff:-
var container = new WindsorContainer();
container.AddFacility<TypedFactoryFacility>();
container.Register(Component.For<ITypedFactoryComponentSelector>()
.ImplementedBy<CommsFactoryComponentSelector>());
container.Register(Component.For<ICommsFactory>()
.AsFactory(o => o.SelectedWith<CommsFactoryComponentSelector>()));
container.Register(Component.For<ICommsService>()
.ImplementedBy<SerialCommsService>().LifeStyle.Singleton);
container.Register(Component.For<ICommsService>()
.ImplementedBy<TcpCommsService>().LifeStyle.Singleton);
Finally, an example class with a dependency on ICommsService:-
public class Test
{
public Test(ICommsFactory commsFactory)
{
var commsService = commsFactory.Create();
...
}
}
As already mentioned, the above solution does work, but I don't like having to inject the factory. It would be more intuitive if I could just inject an ICommsService, and let something somewhere figure out which implementation to resolve and inject - similar to what I'm doing now but earlier in Windsor's "resolving pipeline". Is something like that possible?
You can use UsingFactoryMethod here:
container.Register(Component.For<ICommsService>().UsingFactoryMethod(kernel => kernel.Resolve<ICommsServiceFactory>().Create()));
You can inject ICommsService to any class now. ICommsServiceFactory can be a simple interface now:
interface ICommsServiceFactory
{
ICommsService Create();
}
I have a Struts2 Action Class configured via annotations. All of the "normal" methods that are annotated with #Action work fine.
However, I need to add a method into the action that returns JSON.
Here is a trimmed down version of my class (dao autowired with Spring):
#Namespace("featureClass")
// define success and input actions for class here
public class FeatureClassAction extends ActionSupport {
FeatureClassDao featureClassDao;
#Autowired
public setFeatureClassDao(FeatureClassDeao featureClassDao) {
this.featureClassDao = featureClassDao;
}
List<FeatureClass> featureClasses;
// snip normal actions
#Action("/featureClassesJSON")
#JSON
public String getFeatureClassesJSON() throws Exception {
featureClasses = featureClassDao.getAll();
return SUCCESS;
}
}
Can anyone assist? If I have to go the struts.xml route, that means moving all of my other actions (which work fine) into it.
I figured I would share the answer, since anyone else with the same problem would likely also face the silence.
I created two actions: FeatureClassAction and FeatureClassJsonAction. FeatureClassAction was annotated as such:
#ParentPackage("struts-default")
#Namespace("/featureClass")
public class FeatureClassAction extends ActionSupport {
FeatureClassJsonAction is annotated like this:
#ParentPackage("json-default")
#Namespace("/featureClass")
public class FeatureClassJsonAction extends ActionSupport {
The method in the JSON Action was annotated like this:
#Action(value="featureClassesJson", results = {
#Result(name="success", type="json")
})
public String getFeatureClassesJSON() throws Exception {
Hope it helps someone.