I need ActionScript Proxy to be castable to a particular interface.
Here is an example without interface:
public dynamic class Tracer extends Proxy {
flash_proxy override function callProperty(method:*, ... args):* {
trace(method + " " + args)
}
}
var t:* = new Tracer()
t.sayHello("123") // prints: "sayHello [123]"
Now I need "t" to be of Talker type (don't ask why, I just love static typing):
public interface Talker {
function sayHello(s:String):void
}
var t:Talker = new Tracer() // throws class cast exception
t.sayHello("123")
The question is: how to cast a proxy?
For example, a solution for Java would be passing a list of interfaces when you create a new Proxy http://download.oracle.com/javase/6/docs/api/java/lang/reflect/Proxy.html
Is it really possible with ActionScript 3?
That's unfortunately not possible in plain actionscript. But I think you can do it with the as commons bytecode API.
what about declaring public dynamic class Tracer extends Proxy implements Talker with all methods that need to be defined?
Related
Does Jodd framework provide mechanism to inject petitebeans references for the objects created by other frameworks.
Below are scenarios
- Domain/Service objects are created by Spring Framework
- Domain objects created are by ORM Frameworks
- These objects need to be injected with Repository/DAO object (Singleton objects registered as PetiteBean via AutomagicPetiteConfigurator)
Below is sample code, after petite container is shutdown, initMethod() is invoked when pc.getBean(Greetings.class).message(null) is invoked and destroyMethod() is not invoked, can you please point me what I am doing wrong?
#PetiteBean("greetings")
public class EnglishGreetings implements Greetings {
#Override
public String message(String message) {
if (message == null) {
return "defaultMessage";
}
return message;
}
#PetiteInitMethod
public void initMethod() {
System.out.println("Entered initMethod");
}
#PetiteDestroyMethod
public void destroyMethod() {
System.out.println("Entered destroyMethod");
}
}
public class GreetingRunner {
final static Logger logger = LoggerFactory.getLogger(GreetingRunner.class);
#PetiteInject
public Greetings greetings;
public static void main(String s[]) {
jodd.log.LoggerFactory.setLoggerFactory(new Slf4jLoggerFactory());
PetiteContainer pc = new PetiteContainer();
AutomagicPetiteConfigurator configurator = new AutomagicPetiteConfigurator();
configurator.setIncludedEntries("com.rans.*");
configurator.configure(pc);
pc.shutdown();
System.out.println(pc.getBean(Greetings.class).message(null));
}
}
Destroy method has not been invoked because of lazy aspect of Petite - if bean has not been used, no destroy method will be called. The same applies to init methods. If bean is not used, Petite simple ignores it.
Now back to the question:
Does Jodd framework provide mechanism to inject petitebeans references for the objects created by other frameworks.
Technically, yes - if you overwrite it :) See PetiteProxettaContainer. You may override getBean and use 3rd party container to fetch the bean. Actually, you may override createBeanDefinitionForRegistration method to register the bean in the different container. To be honest, we might make this more obvious :)
(Sorry for late response)
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();
}
My application uses the "SignalR" client/server comms framework. If you aren't familiar with it, the server-side app typically contains one or more "hub" classes (similar to asmx web services), each providing methods that can be called by a client. During startup, the client needs to first create a connection, then create a "proxy" for each hub that it will need to talk to, e.g.:-
var hubConnection = new HubConnection("http://...");
var fooHubProxy = hubConnection.CreateHubProxy("FooHub");
var barHubProxy = hubConnection.CreateHubProxy("BarHub");
...etc...
The string parameter passed to CreateHubProxy() is the name of the server-side hub class. The method return type is IHubProxy.
It feels like I should be able to utilise Windsor here, but I'm struggling to find a solution. My first thought was to instantiate the hub proxies and register these instances with Windsor (by name), e.g.
var fooHubProxy = hubConnection.CreateHubProxy("FooHub");
container.Register(Component.For<IHubProxy>().Instance(fooHubProxy).LifestyleSingleton().Named("FooHub"));
...etc...
The problem is that when a class needs a hub proxy, the only way to resolve it by name is to use service locator pattern, which isn't recommended. What other Windsor features (e.g. typed factories, etc.) might be useful here?
Edit
I've just found Windsor's .UsingFactoryMethod, and am wondering if this would work, to simplify hub registration:
container.Register(Component.For<IHubProxy>()
.UsingFactoryMethod((kernel, context) => hubConnection.CreateHubProxy("FooHub"))
.LifestyleSingleton()
.Named("FooHub"));
I guess I still have the problem of how to resolve by name though.
Two years later, but I have a more elegant solution for other people that stummble accross this problem too.
It is possible to use TypedFactory facility and adapt it to you needs like here.
first create the factory interface (only! no need for the actual implementation, castle will take care of that):
public interface IHubProxyFactory
{
IHubProxy GetProxy(string proxyName);
}
Now we need a class that extend the default typed facotory and retreives the component's name from the input (proxyName):
class NamedTypeFactory : DefaultTypedFactoryComponentSelector
{
protected override string GetComponentName(MethodInfo method, object[] arguments)
{
string componentName = null;
if (arguments!= null && arguments.Length > 0)
{
componentName = arguments[0] as string;
}
if (string.IsNullOrEmpty(componentName))
componentName = base.GetComponentName(method, arguments);
return componentName;
}
}
And then register the factory with castle and specify that your NamedTypeFactory will be used:
Component.For<IHubProxyFactory>().AsFactory(new NamedTypeFactory())
Now every class can get the factory interface in its constructor:
public class SomeClass
{
private IHubProxy _fooHub;
private IHubProxy _barHub;
public SomeClass(IHubProxyFactory hubProxyFactory)
{
_fooHub = hubProxyFactory.GetProxy("FooHub");
_barHub = hubProxyFactory.GetProxy("BarHub");
}
}
Okay, I think I've found a possible solution, partly using the approach detailed here which shows how it is possible to register Func<>s with Windsor.
First, I register a delegate (Func<>) that uses the container to resolve by name:-
Container.Register(Component.For<Func<string, IHubProxy>>()
.Instance(name => Container.Resolve<IHubProxy>(name))
.LifestyleSingleton());
Think of this as an IHubProxy "factory".
Next, I register my hub proxies as detailed in my original question:-
container.Register(Component.For<IHubProxy>()
.UsingFactoryMethod((kernel, context) => hubConnection.CreateHubProxy("FooHub"))
.LifestyleSingleton()
.Named("FooHub"));
container.Register(Component.For<IHubProxy>()
.UsingFactoryMethod((kernel, context) => hubConnection.CreateHubProxy("BarHub"))
.LifestyleSingleton()
.Named("BarHub"));
Here is an example of a class that needs instances of the hub proxies:-
public class SomeClass
{
private IHubProxy _fooHub;
private IHubProxy _barHub;
public SomeClass(Func<string, IHubProxy> hubProxyFactory)
{
_fooHub = hubProxyFactory("FooHub");
_barHub = hubProxyFactory("BarHub");
}
}
Untried so far, but it looks promising. It's a clever solution but injecting the Func<> feels a little hacky, so I would still be keen to hear of other possible solutions to my problem.
I just used a similar method to yours. I use a typed Factory. Advantage is I have type safety for my hubs. Registering the hubs is the same. The rest differs a bit but is technical the same.
IServiceFactory {
IHubProxy GetFooHub();
IHubProxy GetBarHub();
}
And Registration:
Container.AddFacility<TypedFactoryFacility>();
Container.Register(Component.For<IServiceFactory>().AsFactory());
Usage:
public class SomeClass
{
private IHubProxy _fooHub;
private IHubProxy _barHub;
public SomeClass(IServiceFactry hubProxyFactory)
{
_fooHub = hubProxyFactory.GetFooHub();
_barHub = hubProxyFactory.GetBarHub();
}
}
Btw. Factory.Get"Name"() resolves by name.
I'm experimenting with interception in Castle Windsor and notice that interceptors seem to be created as decorators of my service interface.
In other words, if I have an interface "ISomethingDoer" and a concrete "ConcreteSomethingDoer", the proxy implements ISomethingDoer but does not inherit from ConcreteSomethingDoer.
This is fine, and no doubt by design, but what I'm wondering is whether I can intercept protected virtual methods in my concrete classes that wouldn't be known by the public interface. I am doing this in order to add logging support, but I might want to log some of the specific internal details of a class.
In my slightly unimaginative test case I have this:
public interface ISomethingDoer
{
void DoSomething(int Count);
}
[Loggable]
public class ConcreteSomethingDoer : ISomethingDoer
{
public void DoSomething(int Count)
{
for (var A = 0; A < Count; A++)
{
DoThisThing(A);
}
}
[Loggable]
protected virtual void DoThisThing(int A)
{
("Doing a thing with " + A.ToString()).Dump();
}
}
So what I want to do is log calls to "DoThisThing" even though it's not part of the interface.
I've managed to get this working in Autofac. (I've created a Linqpad script here: http://share.linqpad.net/frn5a2.linq) but am struggling with Castle Windsor (see http://share.linqpad.net/wn7877.linq)
In both cases my interceptor is the same and looks like this:
public class Logger : IInterceptor
{
public void Intercept(IInvocation Invocation)
{
String.Format("Calling method {0} on type {1} with parameters {2}",
Invocation.Method.Name,
Invocation.InvocationTarget.GetType().Name,
String.Join(", ", Invocation.Arguments.Select(a => (a ?? "*null*").ToString()).ToArray())).Dump();
Invocation.Proceed();
"Done".Dump();
}
}
What I really want to do is say "any classes with a [Loggable] attribute, should use the logging interceptor". In the Autofac example I've specifically attached a logger to the registration, whereas with Castle I'm using an IModelInterceptorsSelector which looks like this:
public class LoggerInterceptorSelector : IModelInterceptorsSelector
{
public bool HasInterceptors(ComponentModel Model)
{
return Model.Implementation.IsDefined(typeof(LoggableAttribute), true);
}
public InterceptorReference[] SelectInterceptors(ComponentModel Model, InterceptorReference[] Interceptors)
{
return new[]
{
InterceptorReference.ForType<Logger>()
};
}
}
Finally, the code to execute all this is:
var Container = new WindsorContainer();
Container.Register(
Component.For<Logger>().LifeStyle.Transient
);
Container.Kernel.ProxyFactory.AddInterceptorSelector(new LoggerInterceptorSelector());
Container.Register(
Component.For<ISomethingDoer>()
.ImplementedBy<ConcreteSomethingDoer>()
.LifeStyle.Transient
);
var Doer = Container.Resolve<ISomethingDoer>();
Doer.DoSomething(5);
When run I would expect to see "Calling method DoThisThing with parameters x" for each time the method is called. Instead I only get the call to DoSomething logged.
I can see why Castle Windsor is doing this, but I'm wondering if there is a way to tweak the behaviour?
(As a side-note I don't want to use Windsor's own interceptor attributes as I don't want to introduce dependencies to Castle outside of my composition root.)
I have tried resolving the ConcreteSomethingDoer specifically and this works, but not if I'm resolving the ISomethingDoer.
Apologies for the long post, and also apologies because I am pretty new to Castle Windsor!
I you could register like:
Container.Register(
Component.For<ISomethingDoer, ConcreteSomethingDoer>()
.ImplementedBy<ConcreteSomethingDoer>()
.LifeStyle.Transient
);
This should create a class proxy by deriving from ConcreteSomethingDoer. However this won't work with dynamic interceptors. However you probably can work around that by creating a facility which registers the interceptor when needed.
I am currently new in ActionScript and I am creating an Interface and Class where class implements Interface.
I have created Interface and Class both in src/com folder. Here is the code what I did till now.
Interface
package com
{
public interface TestData
{
function getInput(str:String):void
function getOutput():String
}
}
Class
package com
{
public class EntityEL implements TestData
{
public var uname:String;
function getOutput():String
{
return uname;
}
function getInput(str:String):void
{
uname = str;
}
public function EntityEL()
{
}
}
}
mxml file
public var etn:EntityEL = new EntityEL();
public function btnClick():void
{
etn.getInput(value.text);
Alert.show(etn.getOutput());
}
<mx:Button label="Button Click" click="{btnClick();}" />
<mx:TextInput id="value" />
I am getting an error "1044: Interface method getInput in namespace com:TestData not implemented by class com:EntityEL."
Please Help me to solve this problem.
The idea of an interface is to define a contract between the caller and callee objects: Which methods can be accessed, which parameters are required, and what kind of data will be returned.
In order for that contract to make any sense, these methods have to be accessible, so that the "outside world" is allowed to call them.
When you omit access modifiers, the Flex compiler assumes internal as the default, which means that classes from within the same package have permission to access the methods - and so to some extent, this contract seems fulfilled. The same would be true for any other namespace.
Strangely enough, Adobe clearly doesn't allow it: Your method implementations have to be public.
However, you can declare your interface as internal, so that only classes from the package are allowed to implement it, and that leaves a way to keep your API internal, as well - if that was your intent.