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)
Related
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();
}
Suppose I have two sets of controllers in Spring:
/jsonapi1/*
/jsonapi2/*
both of which return objects that are to be interpretted as JSON text.
I'd like some kind of filter to wrap the responses from one set of these controllers so that:
the original response is contained within another object.
For example, if /jsonapi1/count returns:
{"num_humans":123, "num_androids":456}
then the response should be wrapped and returned as follows:
{ "status":0,
"content":{"num_humans":123, "num_androids":456}
}
if an exception happens in the controller, then filter should catch the exception and report it as follows
{ "status":5,
"content":"Something terrible happened"
}
The responses from the other controllers are returned unchanged.
We're currently customizing a MappingJackson2HttpMessageConverter passed to WebMvcConfigurerAdapter.configureMessageConverters in order to perform the above tasks. Works great except that it doesn't seem possible for this approach to be selective about the URLs (or controller classes) it applies to.
Is it possible to apply these kinds of wrappers to individual controller classes or URLs?
Update: Servlet filters look like a solution. Is it possible chose which filter gets applied to which controller methods, or which URLs?
I was struggling on this for multiple days. The solution by #Misha didn't work for me. I was able to finally get this working using ControllerAdvice and ResponseBodyAdvice.
ResponseBodyAdvice allows to inject custom transformation logic on the response returned by a controller but before it is converted to HttpResponse and committed.
This is how my controller method looks:
#RequestMapping("/global/hallOfFame")
public List<HallOfFame> getAllHallOfFame() {
return hallOfFameService.getAllHallOfFame();
}
Now i wanted to add some standard fields around the response like devmessage and usermessage. That logic goes into the ResponseAdvice:
#ControllerAdvice
public class TLResponseAdvice implements ResponseBodyAdvice<Object> {
#Override
public boolean supports(MethodParameter returnType, Class<? extends HttpMessageConverter<?>> converterType) {
return true;
}
#Override
public Object beforeBodyWrite(Object body, MethodParameter returnType, MediaType selectedContentType,
Class<? extends HttpMessageConverter<?>> selectedConverterType, ServerHttpRequest request,
ServerHttpResponse response) {
// TODO Auto-generated method stub
final RestResponse<Object> output = new RestResponse<>();
output.setData(body);
output.setDevMessage("ResponseAdviceDevMessage");
output.setHttpcode(200);
output.setStatus("Success");
output.setUserMessage("ResponseAdviceUserMessage");
return output;
}
}
The entity classes look like this:
#Setter // All lombok annotations
#Getter
#ToString
public class RestResponse<T> {
private String status;
private int httpcode;
private String devMessage;
private String userMessage;
private T data;
}
#Entity
#Data // Lombok
public class HallOfFame {
#Id
private String id;
private String name;
}
To handle exceptions, simply create another ControllerAdvice with ExceptionHandler. Use the example in this link.
Advantages of this solution:
It keeps your controllers clean. You can support any return type from your controller methods.
Your controller return type class does not need to extend some base class as required by the AOP approach.
You do not need to hack your way through Spring filters by using HttpServletResponseWrappers. They come up with a performance penalty.
EDIT - 17th September 2019
To handle exceptions use #ExceptionHandler. Refer code below.
#ExceptionHandler(Exception.class)
#ResponseBody
public MyResponseEntity<Object> handleControllerException(HttpServletRequest request, Throwable ex) {
// default value
int httpCode = HttpStatus.INTERNAL_SERVER_ERROR.value();
if(ex instanceof ResourceNotFoundException) {
httpCode = HttpStatus.NOT_FOUND.value();
}
...
}
The way I understand your question, you have exactly three choices.
Option #1
Manually wrap your objects in simple SuccessResponse, ErrorResponse, SomethingSortOfWrongResponse, etc. objects that have the fields you require. At this point, you have per-request flexibility, changing the fields on one of the response wrappers is trivial, and the only true drawback is code repetition if many of the controller's request methods can and should be grouped together.
Option #2
As you mentioned, and filter could be designed to do the dirty work, but be wary that Spring filters will NOT give you access to request or response data. Here's an example of what it might look like:
#Component
public class ResponseWrappingFilter extends GenericFilterBean {
#Override
public void doFilter(
ServletRequest request,
ServletResponse response,
FilterChain chain) {
// Perform the rest of the chain, populating the response.
chain.doFilter(request, response);
// No way to read the body from the response here. getBody() doesn't exist.
response.setBody(new ResponseWrapper(response.getStatus(), response.getBody());
}
}
If you find a way to set the body in that filter, then yes, you could easily wrap it up. Otherwise, this option is a dead end.
Option #3
A-ha. So you got this far. Code duplication is not an option, but you insist on wrapping responses from your controller methods. I'd like to introduce the true solution - aspect-oriented programming (AOP), which Spring supports fondly.
If you're not familiar with AOP, the premise is as follows: you define an expression that matches (like a regular expression matches) points in the code. These points are called join points, while the expressions that match them are called pointcuts. You can then opt to execute additional, arbitrary code, called advice, when any pointcut or combination of pointcuts are matched. An object that defines pointcuts and advice is called an aspect.
It's great for expressing yourself more fluently in Java. The only drawback is weaker static type checking. Without further ado, here's your response-wrapping in aspect-oriented programming:
#Aspect
#Component
public class ResponseWrappingAspect {
#Pointcut("within(#org.springframework.stereotype.Controller *)")
public void anyControllerPointcut() {}
#Pointcut("execution(* *(..))")
public void anyMethodPointcut() {}
#AfterReturning(
value = "anyControllerPointcut() && anyMethodPointcut()",
returning = "response")
public Object wrapResponse(Object response) {
// Do whatever logic needs to be done to wrap it correctly.
return new ResponseWrapper(response);
}
#AfterThrowing(
value = "anyControllerPointcut() && anyMethodPointcut()",
throwing = "cause")
public Object wrapException(Exception cause) {
// Do whatever logic needs to be done to wrap it correctly.
return new ErrorResponseWrapper(cause);
}
}
The final result will be the non-repeating response wrapping that you seek. If you only want some or one controller receive this effect, then update the pointcut to match methods only within instances of that controller (rather than any class holding the #Controller annotation).
You'll need to include some AOP dependencies, add the AOP-enabling annotation in a configuration class, and make sure something component-scans the package this class is in.
Simplest way i manage custom responses from controllers is by utilising the Map variable.
so your code ends up looking like:
public #ResponseBody Map controllerName(...) {
Map mapA = new HashMap();
mapA.put("status", "5");
mapA.put("content", "something went south");
return mapA;
}
beauty of is is that you can configure it any thousand ways.
Currently i use for object transmition, custom exception handling and data reporting, too easy.
Hope this helps
I am also using AOP with #Around. Developed a custom annotation and using that for point cut. I am using a global Response. It has the status, Message and data which is of type List of type
List <? extends parent> dataList
( which can solve your class cast exception). All the entities extends this Parent class. This way I can set all the data into my List.
Also I am using the message key as param with the custom annotation and setting it in action.
Hope this helps.
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.
Hi I am new to unit testing. Is it possible to access methods that are private?
A very simple example
ObjectA
----------
File file;
private void setupFile (){
//do something
file = "C:\file.dat"
}
In TestCase
File sth = ObjectA.setupFile();
assertNotNull(sth);
I am unable to test whether the file variable is null in method ObjectA.setup()
as I cannot run ObjectA.setupFile()
I am not sure about whether doing like this make sense in terms of unit testing.
So is that a better practice to write every method returning sth and set them public for easier unit testing?
Thanks in advance
In general, you should avoid changing the access of a method/field to enable testing. If you do this then you risk developers using the method directly.
However, if you do need to, then making it protected as Deco says is a good way, so it's accessible from the JUnit tests. If you do this, make sure that it is well documented that this is an method for internal use.
A better way is to test the behaviour of the public methods; you shouldn't care about internal implementation details of a class, so you should only be testing public methods. It's hard to tell from your code, but presumably, the setupFile() has effects later on other methods, so you can test those effects, not the fact that file is not null.
External dependencies (such as dependencies on file system, environment variables) can be worked around in your tests, or injected directly into the class. For the general principle, see my answer to How to test code dependent on environment variables using JUnit?
If it is not absolutely necessary to have the method as private, you can have it as package private (i.e. default access) so that you can call it directly in a JUnit test.
Package private methods can only be used in the package that they are declared, and do not become part of the API of the class. You declare a method package private by putting no modifier on it's declaration.
Here's an example to demonstrate:
public class MyClass() {
int foo;
public MyClass() {
this.foo = 0;
}
void notSoComplexCalculationMethod(int a) {
foo = a * 2;
}
//Other methods here . . .
}
public class MyClassTest extends TestCase {
private MyClass myClass;
protected void setUp() {
super.setUp();
myClass = new MyClass();
}
public void testNotSoComplexCalculationMethod() {
int a = 2;
assertEquals(4, myClass.notSoComplexCalculationMethod(a));
//Unit test passes, yay! Now you've tested a package private method.
}
}
I am working on a web application which I need to localize and internationalize. It occurred to me that I could do this using a dependency injection framework. Let's say I declare an interface ILocalResources (using C# for this example but that's not really important):
interface ILocalResources {
public string OkString { get; }
public string CancelString { get; }
public string WrongPasswordString { get; }
...
}
and create implementations of this interface, one for each language I need to support. I would then setup my DI framework to instantiate the proper implementation, either statically or dynamically (for example based on the requesting browsers preferred language).
Is there some reason I shouldn't be using a DI framework for this sort of thing? The only objection I could find myself is that it might be a bit overkill, but if I'm using a DI framework in my web app anyway, I might as well use it for internationalization as well?
A DI framework is built to do dependency injection and localization could just be one of your services, so in that case there's no reason not to use a DI framework IMO. Perhaps we should start discussing the provided ILocalResources interface. While I'm a favor of having compile time support, I'm not sure the supplied interface will help you, because that interface will be probably the type in your system that will change the most. And with that interface the type/types that implement it. Perhaps you should go with a different design.
When we look at most localization frameworks/providers/factories (or whatever), they're all string based. Because of this, think about the following design:
public interface ILocalResources
{
string GetStringResource(string key);
string GetStringResource(string key, CultureInfo culture);
}
This would allow you to add keys and cultures to the underlying message data store, without changing the interface. Downside is of course that you should never change a key, because that will probably be a hell.
Another approach could be an abstract base type:
public abstract class LocalResources
{
public string OkMessage { get { return this.GetString("OK"); } }
public string CancelMessage { get { return this.GetString("Cancel"); } }
...
protected abstract string GetStringResource(string key,
CultureInfo culture);
private string GetString(string key)
{
Culture culture = CultureInfo.CurrentCulture;
string resource = GetStringResource(key, culture);
// When the resource is not found, fall back to the neutral culture.
while (resource == null && culture != CultureInfo.InvariantCulture)
{
culture = culture.Parent;
resource = this.GetStringResource(key, culture);
}
if (resource == null) throw new KeyNotFoundException(key);
return resource;
}
}
And implementation of this type could look like this:
public sealed class SqlLocalResources : LocalResources
{
protected override string GetStringResource(string key,
CultureInfo culture)
{
using (var db = new LocalResourcesContext())
{
return (
from resource in db.StringResources
where resource.Culture == culture.Name
where resource.Key == key
select resource.Value).FirstOrDefault();
}
}
}
This approach takes best of both worlds, because the keys won't be scattered through the application and adding new properties just has to be done in one single place. Using your favorite DI library, you can register an implementation like this:
container.RegisterSingleton<LocalResources>(new SqlLocalResources());
And since the LocalResources type has exactly one abstract method that does all the work, it is easy to create a decorator that adds caching to prevent requesting the same data from the database:
public sealed class CachedLocalResources : LocalResources
{
private readonly Dictionary<CultureInfo, Dictionary<string, string>> cache =
new Dictionary<CultureInfo, Dictionary<string, string>>();
private readonly LocalResources decoratee;
public CachedLocalResources(LocalResources decoratee) { this.decoratee = decoratee; }
protected override string GetStringResource(string key, CultureInfo culture) {
lock (this.cache) {
string res;
var cultureCache = this.GetCultureCache(culture);
if (!cultureCache.TryGetValue(key, out res)) {
cultureCache[key] = res= this.decoratee.GetStringResource(key, culture);
}
return res;
}
}
private Dictionary<string, string> GetCultureCache(CultureInfo culture) {
Dictionary<string, string> cultureCache;
if (!this.cache.TryGetValue(culture, out cultureCache)) {
this.cache[culture] = cultureCache = new Dictionary<string, string>();
}
return cultureCache;
}
}
You can apply the decorator as follows:
container.RegisterSingleton<LocalResources>(
new CachedLocalResources(new SqlLocalResources()));
Do note that this decorator caches the string resources indefinitely, which might cause memory leaks, so you wish to wrap the strings in WeakReference instances or have some sort of expiration timeout on it. But the idea is that you can apply caching without having to change any existing implementation.
I hope this helps.
If you cannot use an existing resource framework (like that built into ASP.Net) and would have to build your own, I will assume that you at some point will need to expose services that provide localized resources.
DI frameworks are used to handle service instantiation. Your localization framework will expose services providing localization. Why shouldn't that service be served up by the framework?
Not using DI for its purpose here is like saying, "I'm building a CRM app but cannot use DI because DI is not built for customer relations management".
So yes, if you're already using DI in the rest of your application, IMO it would be wrong to not use it for the services handling localization.
The only disadvantage I can see is that for any update to "resources", you would have to recompile the assembly containing resources. And depending on your project, this disadvantage may be a good advise to only use a DI framework for resolving a ResourceService of some kind, rather than the values itself.