I'm experimenting with Angular 2 and Dart. By the end of this step of the tutorial the class DisplayComponent has a Component annotation with viewBindings set:
#Component(selector: 'display', viewBindings: const [FriendsService])// this viewBinding
#View(...)
class DisplayComponent {
...
}
Atom with the angular2-dart plugin tells me that viewBindings is deprecated. This seems in-line with the documentation.
I've tried simply removing the variable from the annotation but I get an Exception saying No provider for FriendsService. What should I be doing instead?
for the sake of completeness
In Alpha 46 is viewProviders (viewBindings => viewProviders) and providers (bindings => providers) up to date.
https://angular.io/docs/ts/latest/api/core/ComponentMetadata-class.html
https://github.com/angular/angular/blob/master/CHANGELOG.md
Related
I am newbie for Guice and seeking help for the following use case :
I have developed one package say (PCKG) where the entry class of that package depends on other class like:
A : Entry point class --> #Inject A(B b) {}
B in turn is dependent on C and D like --> #Inject B(C c, D d) {}
In my binding module I am doing :
bind(BInterface).to(Bimpl);
bind(CInterface).to(CImpl);
...
Note I am not providing binding information for A as i want to provide its binding by its consumer class. (this is how the design is so my request is to keep the discussion on main problem rather than design).
Now my consumer class is doing like:
AModule extends PrivateModule {
protected void configure() {
bind(AInterface.class).annotatedWith(AImpl.class);
}
}
Also in my consumer package:
.(new PCKGModule(), new AModule())
Q1. Am i doing the bindings correctly in consumer class. I am confused because when i am doing some internal testing as below in my consumer package:
class testModule {
bind(BInterface).to(Bimpl);
bind(CInterface).to(CImpl)...
}
class TestApp {
public static void main(..) {
Guice.createInstance(new testModule());
Injector inj = Guice.createInstance(new AModule());
A obj = inj.getInstance(A.class);
}
}
It is throwing Guice creation exception.Please help me get rid of this situation.
Also one of my friend who is also naive to Guice was suggesting that I need to create B's instance in AModule using Provides annotation. But i really didn't get his point.
Your main method should look like this:
class TestApp {
public static void main(..) {
Injector injector = Guice.createInjector(new TestModule(), new AModule());
A obj = injector.getInstance(A.class);
}
Note that the Java convention is for class names to have the first letter capitalised.
I'm pretty sure your implementation of AModule isn't doing what you think it's doing either, but it's hard to be certain based on the information you've provided. Most likely, you mean to do this:
bind(AInterface.class).to(AImpl.class)`
There's no need to do anything "special" with A's binding. Guice resolves all the recursion for you. That's part of its "magic".
annotatedWith() is used together with to() or toInstance(), like this:
bind(AInterface.class).to(AImpl.class).annotatedWIth(Foo.class);
bind(AInterface.class).to(ZImpl.class).annotatedWIth(Bar.class);
Then you can inject different implementations by annotating your injection points, e.g.:
#Inject
MyInjectionPoint(#Foo AInterface getsAImpl, #Bar AInterface getsZImpl) {
....
}
It's worth also pointing out that you can potentially save yourself some boilerplate by not bothering with the binding modules (depending how your code is arranged) and using JIT bindings:
#ImplementedBy(AImpl.class)
public interface AInterface {
....
}
These effectively act as "defaults" which are overridden by explicit bindings, if they exist.
I have read several articles on dependency injection and cannot seem to get it working the way I think it should. From what I have read, you can use the #Injectable decorator on a class and then the metadata is created for the DI like so:
import {Hero} from './hero.model';
import {Injectable} from 'angular2/angular2'
#Injectable()
export class HeroService {
constructor() {
console.log('Hero Service Created');
}
}
Then in your component, you can use it in your constructor (with the proper import) like this:
constructor(heroService: HeroService) {
console.log('App Component Created');
}
However, I get the following error: Cannot resolve all parameters for AppComponent(?). Make sure they all have valid type or annotations.
I am able to get it working properly if I remove the #Injectable syntax from the service and instead have my constructor like this:
constructor(#Inject(HeroService) heroService: HeroService) {
console.log('App Component Created');
}
With everything that I've read, these should do the same thing, but they aren't. Any ideas as to why? I am using Typescript 1.6.2 with VS 2013, angular 2 v2.0.0-alpha.46, and systemjs v0.19.5.
Make sure that you've specified "emitDecoratorMetadata" option in your TypeScript configuration.
I'm following the tutorials display-data in angular.io.
I introduced a new class FriendsService to separate the controller logic and model concern. I Called FriendsService class in DisplayComponent class by using dependency injection, the dependency injection not working.
There's no errors in the console. The page doesn't display the component. This is the line causing the component not to display on the page.
constructor(friendsService: FriendsService)
The page loads and displays the components (display) if change the constructor to:
constructor()
I'm using angular2.alpha.34 , Typescript, ES6.
I solved it. Eclipse-Plugin was causing the issue. The plugin wasn't generating the ES5 complaint correct code.
I used "tsc --watch -m commonjs -t es5 --emitDecoratorMetadata app.ts" command described in angular.io website.
The eclipse-plugin generated code and the command "tsc" generated code is slightly different.
When using the "tsc" command I was achieving the expected behavior.
First you have to define the Service before that any component or directive.
If you have something like this
class Component {
constructor(svc: Service) {
}
}
class Service {
}
It will fail. In cases like this you should use fordwardRef or you just can declare it before your component.
class Service {
}
class Component {
constructor(svc: Service) {
}
}
Another thing is that you have to inject your service using viewBindings (see ComponentAnnotation documentation).
class Service {
}
#Component({
viewBindings: [Service]
})
class Component {
constructor(svc: Service) {
}
}
And you are good to go. I hope it helps.
I need to intercept calls to private methods in Grails services. The following aspect IS working for any annotated public methods, however nothing happens when the annotation is at PRIVATE methods.
import exceptions.DwcpExeption
import org.aspectj.lang.ProceedingJoinPoint
import org.aspectj.lang.annotation.Around
import org.aspectj.lang.annotation.Aspect
import org.slf4j.Logger
import org.slf4j.LoggerFactory
import org.springframework.stereotype.Component
#Aspect
#Component
public class LoggerInterceptor {
private static Logger log = LoggerFactory.getLogger(LoggerInterceptor.class);
#Around("#annotation(newAnnotation)")
public Object aroundEvents(ProceedingJoinPoint proceedingJoinPoint, NewAnnotation newAnnotation) {
log.info newAnnotation.value()
String logMessage = String.format("%s.%s(%s)",
proceedingJoinPoint.getTarget().getClass().getName(),
proceedingJoinPoint.getSignature().getName(),
Arrays.toString(proceedingJoinPoint.getArgs()));
log.info "*Entering $logMessage"
def result
try {
result = proceedingJoinPoint.proceed()
catch (ex) {
log.error '', ex
}
log.info "*Exiting $logMessage. Result: $result"
return result
}
}
Maybe the problem is in config? I've tried in applicationContext.xml
<aop:aspectj-autoproxy proxy-target-class="true"/>
and in resources.groovy
aop.config("proxy-target-class": true)
Nevertheless, only public methods are intercepted.
Spring AOP is a proxy-based "AOP lite" approach in comparison to AspectJ. It only works for Spring components and only for public, non-static methods. This is also explained in the Spring AOP documentation as follows:
Due to the proxy-based nature of Spring’s AOP framework, protected methods are by definition not intercepted, neither for JDK proxies (where this isn’t applicable) nor for CGLIB proxies (where this is technically possible but not recommendable for AOP purposes). As a consequence, any given pointcut will be matched against public methods only!
If your interception needs include protected/private methods or even constructors, consider the use of Spring-driven native AspectJ weaving instead of Spring’s proxy-based AOP framework. This constitutes a different mode of AOP usage with different characteristics, so be sure to make yourself familiar with weaving first before making a decision.
Bottom line: Please switch to AspectJ which can be easily integrated into Spring applications via LTW (load-time weaving) as described in Section 9.8, “Using AspectJ with Spring applications”.
If you don't specify the scope it defaults to public. Add a pointcut for private methods:
#Around("#annotation(newAnnotation) && execution(private * *(..))")
This question is a follow up question to this question. After upgrading to polymer 0.8.7 the following code stopped working:
DocumentFragment instanceTemplate(Element template) =>
template.createInstance(this,
new PolymerExpressions(globals: {
'splitnewline': (String input) => input.split("\n")
}));
Looks like Element doesn't contain a method createInstance anymore. How can I register a own polymer expression in polymer 0.8.7?
PS: I also used the method job() in the past, does anybody know where I can find it now?
With polymer 0.8.7 you have to import an additional package and call templateBind on the element.
import 'package:template_binding/template_binding.dart';
// ... fancy code in between ...
DocumentFragment instanceTemplate(Element template) =>
templateBind(template).createInstance(this,
new PolymerExpressions(globals: {
'splitnewline': (String input) => input.split("\n")
}));
Don't know about the job() method though.