I've got my application setup to use CDI and all is going well. Now I'm creating a new bean that extends a class from a 3rd party library. I attempted to create something like the below example:
#Named("myNewClass")
#ConversationScoped
public class MyNewClass extends ThirdPartyClass {
#Inject
private ApplicationConfig applicationConfig;
#Override
public void doStuff() {
// In this code, applicationConfig will be null.
}
}
When doStuff is called, applicationConfig was always null. I added a no args constructor & a method tagged with #PostConstruct to try and see what was going on. The constructor gets called then the doStuff method. As doStuff is being called at construction time I cannot use the #Inject annotations at this point.
So my question is how do I get a hold of applicationConfig at this point?
I've been tinkering with BeanManager (this is in a function I call with ApplicationConfig.class as a parameter):
Context initCtx = new InitialContext();
Context envCtx = (Context) initCtx.lookup("java:comp/env");
BeanManager beanManager = (BeanManager) envCtx.lookup("BeanManager");
Bean myBean = beanManager.getBeans(clazz).iterator().next();
return beanManager.getReference(myBean, clazz, beanManager.createCreationalContext(myBean));
Which works but it's creating a new ApplicationConfig instance. I want to get the one that I know already exists on my ConversationScope.
A little info: I'm using Seam 3.0, Weld Servlet 1.1.1 and this is running on Tomcat 6.
You can annotate a constructor with #Inject then any parameters of the constructor become injection points which the BeanManager will resolve. It's certainly not the desired way of doing it, but if it works for you, go for it.
Related
When using spring-data-rest there is a post processing of Resource classes returned from Controllers (e.g. RepositoryRestControllers). The proper ResourceProcessor is called in the post processing.
The class responsible for this is ResourceProcessorHandlerMethodReturnValueHandler which is part of spring-hateoas.
I now have a project that only uses spring-hateoas and I wonder how to configure ResourceProcessorHandlerMethodReturnValueHandler in such a scenario. It looks like the auto configuration part of it still resides in spring-data-rest.
Any hints on how to enable ResourceProcessorHandlerMethodReturnValueHandler in a spring-hateoas context?
I've been looking at this recently too, and documentation on how to achieve this is non-existent. If you create a bean of type ResourceProcessorInvokingHandlerAdapter, you seem to lose the the auto-configured RequestMappingHandlerAdapter and all its features. As such, I wanted to avoid using this bean or losing the WebMvcAutoConfiguration, since all I really wanted was the ResourceProcessorHandlerMethodReturnValueHandler.
You can't just add a ResourceProcessorHandlerMethodReturnValueHandler via WebMvcConfigurer.addReturnValueHandlers, because what we need to do is actually override the entire list, as is what happens in ResourceProcessorInvokingHandlerAdapter.afterPropertiesSet:
#Override
public void afterPropertiesSet() {
super.afterPropertiesSet();
// Retrieve actual handlers to use as delegate
HandlerMethodReturnValueHandlerComposite oldHandlers = getReturnValueHandlersComposite();
// Set up ResourceProcessingHandlerMethodResolver to delegate to originally configured ones
List<HandlerMethodReturnValueHandler> newHandlers = new ArrayList<HandlerMethodReturnValueHandler>();
newHandlers.add(new ResourceProcessorHandlerMethodReturnValueHandler(oldHandlers, invoker));
// Configure the new handler to be used
this.setReturnValueHandlers(newHandlers);
}
So, without a better solution available, I added a BeanPostProcessor to handle setting the List of handlers on an existing RequestMappingHandlerAdapter:
#Component
#RequiredArgsConstructor
#ConditionalOnBean(ResourceProcessor.class)
public class ResourceProcessorHandlerMethodReturnValueHandlerConfigurer implements BeanPostProcessor {
private final Collection<ResourceProcessor<?>> resourceProcessors;
#Override
public Object postProcessAfterInitialization(Object bean, String beanName)
throws BeansException {
if (bean instanceof RequestMappingHandlerAdapter) {
RequestMappingHandlerAdapter requestMappingHandlerAdapter = (RequestMappingHandlerAdapter) bean;
List<HandlerMethodReturnValueHandler> handlers =
requestMappingHandlerAdapter.getReturnValueHandlers();
HandlerMethodReturnValueHandlerComposite delegate =
handlers instanceof HandlerMethodReturnValueHandlerComposite ?
(HandlerMethodReturnValueHandlerComposite) handlers :
new HandlerMethodReturnValueHandlerComposite().addHandlers(handlers);
requestMappingHandlerAdapter.setReturnValueHandlers(Arrays.asList(
new ResourceProcessorHandlerMethodReturnValueHandler(delegate,
new ResourceProcessorInvoker(resourceProcessors))));
return requestMappingHandlerAdapter;
}
else return bean;
}
}
This has seemed to work so far...
I want to load Spring initial context inside a AWS lambda handler class. This class is the starting point of my application. I did it in the below way.
#SpringBootApplication
public class LambdaFunctionHandler implements RequestHandler<KinesisEvent, Object> {
#Override
public Object handleRequest(KinesisEvent input, Context context) {
AnnotationConfigApplicationContext appContext = new AnnotationConfigApplicationContext(LambdaFunctionHandler.class);
LambdaFunctionHandler lambdaHandlerBean = appContext.getBean(LambdaFunctionHandler.class);
// some business logic call
return null;
}
}
This is working fine but I'm getting warning on appContext that it should be closed as it is resource leak. this can be fixed by calling appContext.close() but my doubt is whether this way of initializing Spring application context in a non main method is correct ? Most recommended way to do in a main method is like below
SpringApplication app = new SpringApplication(LambdaFunctionHandler.class);
ConfigurableApplicationContext context = app.run(args);
LambdaFunctionHandler lambdaFunctionHandler =
context.getBean(LambdaFunctionHandler.class);
But I don't have the value to replace the args in my case. can anyone suggest the right way of doing this
You can simple class with main method for #SpringBootApplication and
use CommandLineRunner for loading AWS lambda handler. Just implement the run to load the bean
https://docs.spring.io/spring-boot/docs/current/api/org/springframework/boot/CommandLineRunner.html
First of all I want to say I'm pretty new in programming with ejb and jsf, and I'm trying to complete a project started by a friend of mine.
I'm getting a NullPointerException caused by the invoke of the method utenteSessionBean.CheckUtentebyId(username) of the session bean object called utenteSessionBean, declared inside the managed bean called Neo4jMBean.
I learned that it's not necessary creating and initializing a session bean (as you must do with a normal java object) in managed bean, but it's enough declaring it.
Here is the code of the session bean, which retrieves data from a DB
#Stateless
#LocalBean
public class UtenteSessionBean {
EntityManagerFactory emf = Persistence.createEntityManagerFactory("EnterpriseApplication2-ejbPU");
public boolean CheckUtentebyId(String username){
EntityManager em = emf.createEntityManager();
Query query = em.createNamedQuery("Utente.findByUsername");
query.setParameter("username", username);
List<Utente> Res=query.getResultList();
//completare funzione ctrl+spazio
System.out.println("pre");
System.out.println("pre"+Res.isEmpty());
em.close();
System.out.println("post");
System.out.println("post"+Res.isEmpty());
if(Res.size()>=1)
{
return true;
}
else
{
return false;
}
}
}
Here's the code of the managed bean:
#ManagedBean
#ViewScoped
public class Neo4jMBean {
#EJB
private UtenteSessionBean utenteSessionBean;
static String SERVER_ROOT_URI = "http://localhost:7474/db/data/";
public Neo4jMBean() {
}
public boolean getUser(String username) {
return utenteSessionBean.CheckUtentebyId(username);
}
}
I've searched on StackOverFlow many times a solution for fixing this problem, but I haven't found something that works for me yet.
I fixed it accessing the EJB Components using JNDI.
In few words, if i use an EJB in a managed bean method, i need to add the next lines of code:
InitialContext ic = new InitialContext();
SessionBeanName = (SessionBeanClass) ic.lookup("java:global/NameOfTheApplication/NameOfTheEJBpackage/NameOfTheSessionBean");
It must be surronded by a try-catch statement
Create empty beans.xml file in your WEB-INF folder to enable CDI
I'm new to EJB and I'm facing my first problem. I'm trying to use an #Schedule method contained in a Stateless EJB. I'd like this method to use a private member variable which would be set at bean creation:
Here's a short example:
#Singleton
#LocalBean
#Startup
public class Starter {
#PostActivate
private void postActivate() {
ScheduleEJB scheduleEjb = new ScheduleEJB("Hello");
}
}
And the schedule bean:
#Stateless
#LocalBean
public class ScheduleEJB {
private String message;
public ScheduleEJB() {
super();
}
public ScheduleEJB(String message) {
super();
this.message= message;
}
#Schedule(second="*/3", minute="*", hour="*", dayOfMonth="*", dayOfWeek="*", month="*", year="*")
private void printMsg() {
System.out.println("MESSAGE : " + message);
}
}
The problem is that my "message" variable is always null when printed in the printMsg() method... What's the best way to achieve this?
Thanks for your help !
You're mixing few things here.
The #PostActivate annotation is to be used on Stateful Session Beans (SFSB), and you use it on the singleton. I guess that you mean the #PostConstruct method which applies to every bean which lifecycle is managed by the container.
You're using a constructor from your EJB. You cannot do:
ScheduleEJB scheduleEjb = new ScheduleEJB("Hello");
as it creates just an instance of this class. It's not an EJB - the container didn't create it, so this class does not have any EJB nature yet.
That's the whole point of dependency injection - you just define what you want and the container is responsible for providing you with an appropriate instance of the resource.
The Stateless Bean (SLSB) is not intented to hold the state. The SFSB is. Even if you would set the message in one SLSB method (i.e. in some ScheduleEJB#setMessage(String) method) than you need to remember that the EJB's are pooled. You don't have any guarantee that the next time you invoke a method on the ScheduleEJB you will get to the same instance.
In your case it would be the easies solution just to add the #Schedule method to your singleton class. Than you can define the variable of your choice in the #PostConstruct method. You can be sure that there is only one Singleton instance per JVM, so your variable will be visible in the Schedule annotated method of the same class.
HTH.
My app has a ProviderFactory static class that has static utility methods passing back static instances of things like a logger. The rest of my app then can just grab a/the reference to the logger from anywhere without having to pass in the logger (common design practice).
So, another part of my app, the DbCacheProvider, has methods that make calls to the logger so internally it gets a reference to the logger from the factory and then issues calls to it.
My question is that using Moq, I want to verify methods on the logger are being called by the methods within the DbCacheProvider. I can do this using dependency injection when I pass a mock logger into the DbCacheProvider as a parameter, but I'm not passing the logger in (not do I want to). So, how would I verify the DbCacheProvider is making calls to the logger?
If you don't want to pass the logger in through the constructor you'd need to change your ProviderFactory while running unit tests to return your mocked logger.
Anyway there are a couple of reasons it's often suggested to set up dependency injection:
Your tests are more straightforward and don't involve finagling with custom factories
IoC frameworks like Unity, Ninject and Autofac make it easy to create objects when their dependencies are set up this way. If you set up all of your objects this way, the framework will do all the heavy lifting of creating the right objects and passing them in for you. The dependency injection is done automatically and won't be a burden for you.
Old question without an answer, I had a similar problem and solved it like this:
I have the following sample code and need to verify that not only was a method called but was called with a specific value.
public interface ILog
{
void Info(string message);
}
public interface ILogFactory
{
ILog GetLogger();
}
This is the class being tested, where the interface items are being injected:
public class NewAction
{
readonly ILogFactory _logger;
public NewAction(ILogFactory logger)
{
_logger = logger;
}
public void Step1()
{
_logger.GetLogger().Info("Step 1");
}
public void Step2()
{
_logger.GetLogger().Info("Step 2");
}
}
This is obviously a very simplistic view of my actual code, but I needed to verify that Step1 and Step2 are behaving as expected and passed the correct values to the Log, this would mean I also needed to ensure they occurred in the right order. My test:
[TestClass]
public class UnitTest1
{
[TestMethod]
public void TestMethod1()
{
// Arrange
var log = new Mock<ILog>();
var factory = new Mock<ILogFactory>();
factory.Setup(l => l.GetLogger()).Returns(log.Object);
// Act
var action = new NewAction(factory.Object);
action.Step1();
action.Step2();
// Assert
factory.Verify(l => l.GetLogger());
log.Verify(l => l.Info(It.Is<string>(s => s == "Step 1")));
log.Verify(l => l.Info(It.Is<string>(s => s == "Step 2")));
}
}
Hope this helps.