Seed value in Weld CDI custom scope - cdi

Coming from a Guice background, I know that it is possible to seed an object value from a scope using.
scope.seed(Key.get(SomeObject.class), someObject);
I suppose one could do this by registering a Bean that gets a value from an AbstractBoundContext, but examples just seeding one value from a Custom Scope seem hard to find. How do I create a custom scope that seeds a value that can be injected elsewhere?
Edit:
I am currently using the following workaround, that can be injected in an interceptor to set the Configuration when entering the scope, and can then be injected through its thread local provider. I am still looking for options that feel less hacky / are more integrated with the scope/scope context system in Weld though.
#Singleton
public class ConfigurationProducer {
private final InheritableThreadLocal<Configuration> threadLocalConfiguration =
new InheritableThreadLocal<>();
#Produces
#ActiveDataSet
public ConfigurationConfiguration() {
return threadLocalConfiguration.get()
}
public void setConfiguration(Configuration configuration) {
threadLocalConfiguration.set(configuration);
}
}

The answer is to register a custom bean with the AfterBeanDiscovery event, like so:
event.addBean()
.createWith(ctx -> commandContext.getCurrentCommandExecution())
.addType(CommandExecution.class)
.addQualifier(Default.Literal.INSTANCE)
.scope(CommandScoped.class)
.beanClass(CommandExtension.class);
There is a quite sophisticated example available at https://github.com/weld/command-context-example

Related

How to properly create an instance of AnnotatedControllerConfigurer

I'm trying to define a configuration to create an ExecutionGraphQlService to wire into an existing application as a proof of concept, but I'm a bit confused about how to create an instance of a AnnotatedControllerConfigurer. Here is what I currently have settled upon.
AnnotatedControllerConfigurer annotatedControllerConfigurer = new AnnotatedControllerConfigurer();
annotatedControllerConfigurer.setApplicationContext(applicationContext);
annotatedControllerConfigurer.afterPropertiesSet();
annotatedControllerConfigurer.configure(runtimeWiringBuilder);
AnnotatedControllerConfigurer implements ApplicationContextAware, InitializingBean so it seems to expect to be initialized as a bean, but attempts to autowire an instance of it fail due to Could not autowire. No beans of 'AnnotatedControllerConfigurer' type found.
I've attempted constructor injection public ExecutionGraphQlService defaultExecutionGraphQlService(AnnotatedControllerConfigurer annotatedControllerConfigurer) as well as manual instantiation autowireCapableBeanFactory.autowireBean(annotatedControllerConfigurer) (which should be basically the same thing).
It seems like this class is not a bean, but expects to be managed by Spring's bean lifecycle? Is my approach the expected approach?
The AnnotatedControllerConfigurer type is meant to be a bean in the Spring container, and is using the bean lifecycle to setup the infrastructure.
Creating it as a bean (given other pieces are contributed as beans as well). The runtime wiring should be configured on the GraphQlSource directly.
#Configuration(proxyBeanMethods = false)
class GraphQlConfiguration {
#Bean
public AnnotatedControllerConfigurer annotatedControllerConfigurer() {
return new AnnotatedControllerConfigurer();
}
}

Override beans from an external library (Quarkus)

I want to override a bean that's used by Quarkus to disable authentication/authorization.
With the following implementation, it works that REST endpoints can be configured at start time to not be secured:
#Alternative
#Priority(1)
#ApplicationScoped
public class CustomOidcAuthController extends TestAuthController {
private static final Logger LOGGER = Logger.getLogger(CustomOidcAuthController.class);
#ConfigProperty(name = "quarkus.oidc.enabled", defaultValue = "false")
boolean quarkusOidcEnabled;
#PostConstruct
public void check() {
LOGGER.info("isAuthorizationEnabled(): " + isAuthorizationEnabled());
}
#Override
public boolean isAuthorizationEnabled() {
return quarkusOidcEnabled;
}
}
This is with the Bean residing in the same Quarkus module.
However, I want to externalize this class into a separate library and if I do this, it no longer works.
Noteworthy:
Yes, the #Priority of my bean (1) is higher than the default (3000)
The beans are discovered, if I explicitly inject them.
They are however not used, if I inject the subtype that Quarkus uses internally (either TestAuthController or AuthorizationController).
Therefore the endpoints are always secured
As can be seen here from the IntelliJ debugger
Currently I have an empty beans.xml, but with building a Jandex Index I also observe the same behavior (related How to create a Jandex index in Quarkus for classes in a external module)
I can get the behavior I want, if I use quarkus.arc.selected-alternatives=com.xxx.CustomOidcAuthController, however this is not preferable, since each Service using the library would need to configure this and this will certainly cause problems, because it can be easily forgotten.
Well, the priority of the TestAuthController is indeed 3000 and therefore it takes precedence. Injection of CustomOidcAuthController works because there's no other bean that has CustomOidcAuthController in its set of bean types.
In other words, it works as expected (and defined by the spec).
Yes, the #Priority of my bean (1) is higher than the default (3000)
According to CDI specification, an alternative with highest priority is selected. See this part of the CDI 2.0 specification.
Here is a CDI TCK test asserting that higher priority 'wins' during typesafe resolution.
Therefore, your approach is correct and you just need to make sure your custom bean is an alternative with priority value higher than that of TestAuthController.

How to use the strategy pattern with managed objects

I process messages from a queue. I use data from the incoming message to determine which class to use to process the message; for example origin and type. I would use the combination of origin and type to look up a FQCN and use reflection to instantiate an object to process the message. At the moment these processing objects are all simple POJOs that implement a common interface. Hence I am using a strategy pattern.
The problem I am having is that all my external resources (mostly databases accessed via JPA) are injected (#Inject) and when I create the processing object as described above all these injected objects are null. The only way I know to populate these injected resources is to make each implementation of the interface a managed bean by adding #stateless. This alone does not solve the problem because the injected members are only populated if the class implementing the interface is itself injected (i.e. container managed) as opposed to being created by me.
Here is a made up example (sensitive details changed)
public interface MessageProcessor
{
public void processMessage(String xml);
}
#Stateless
public VisaCreateClient implements MessageProcessor
{
#Inject private DAL db;
…
}
public MasterCardCreateClient implements MessageProcessor…
In the database there is an entry "visa.createclient" = "fqcn.VisaCreateClient", so if the message origin is "Visa" and the type is "Create Client" I can look up the appropriate processing class. If I use reflection to create VisaCreateClient the db variable is always null. Even if I add the #Stateless and use reflection the db variable remains null. It's only when I inject VisaCreateClient will the db variable get populated. Like so:
#Stateless
public QueueReader
{
#Inject VisaCreateClient visaCreateClient;
#Inject MasterCardCreateClient masterCardCreateClient;
#Inject … many more times
private Map<String, MessageProcessor> processors...
private void init()
{
processors.put("visa.createclient", visaCreateClient);
processors.put("mastercard.createclient", masterCardCreateClient);
… many more times
}
}
Now I have dozens of message processors and if I have to inject each implementation then register it in the map I'll end up with dozens of injections. Also, should I add more processors I have to modify the QueueReader class to add the new injections and restart the server; with my old code I merely had to add an entry into the database and deploy the new processor on the class path - didn't even have to restart the server!
I have thought of two ways to resolve this:
Add an init(DAL db, OtherResource or, ...) method to the interface that gets called right after the message processor is created with reflection and pass the required resource. The resource itself was injected into the QueueReader.
Add an argument to the processMessage(String xml, Context context) where Context is just a map of resources that were injected into the QueueReader.
But does this approach mean that I will be using the same instance of the DAL object for every message processor? I believe it would and as long as there is no state involved I believe it is OK - any and all transactions will be started outside of the DAL class.
So my question is will my approach work? What are the risks of doing it that way? Is there a better way to use a strategy pattern to dynamically select an implementation where the implementation needs access to container managed resources?
Thanks for your time.
In a similar problem statement I used an extension to the processor interface to decide which type of data object it can handle. Then you can inject all variants of the handler via instance and simply use a loop:
public interface MessageProcessor
{
public boolean canHandle(String xml);
public void processMessage(String xml);
}
And in your queueReader:
#Inject
private Instance<MessageProcessor> allProcessors;
public void handleMessage(String xml) {
MessageProcessor processor = StreamSupport.stream(allProcessors.spliterator(), false)
.filter(proc -> proc.canHandle(xml))
.findFirst()
.orElseThrow(...);
processor.processMessage(xml);
}
This does not work on a running server, but to add a new processor simply implement and deploy.

RESTEasy, CDI, embedded Jetty, bean validation is ignored

I've a Groovy project where I use RESTEasy with Weld and deploy to embedded Jetty. What I can't seem to get working is bean validation. RESTEasy documentation says that adding resteasy-validator-provider-11 along with hibernate validator dependencies (hibernate-validator, hibernate-validator-cdi, javax.el-api, javax.el) is enough. But the bean validation is simply ignored by RESTEasy. I curiously also get the following message in the logs:
plugins.validation.ValidatorContextResolver - Unable to find CDI supporting ValidatorFactory. Using default ValidatorFactory
Based on the suggestions on [this][1] post, I tried registering Hibernate InjectingConstraintValidatorFactory in META-INF/validation.xml but it depends on a BeanManager being injected and blows up at runtime.
The code can be found here https://github.com/abhijitsarkar/groovy/tree/master/movie-manager/movie-manager-web
A log gist is here: https://gist.github.com/anonymous/8947319
I've tried everything under the sun without any success. Pls help.
To do this without EE, I believe you'll need to fork the existing InjectingConstraintValidatorFactory but instead of using injection of the bean manager, use the CDI 1.1 class CDI to get a reference to the bean manager, e.g. CDI.current().getBeanManager(). http://docs.jboss.org/cdi/api/1.1/javax/enterprise/inject/spi/CDI.html
You do need to be on CDI 1.1 to do this (so Weld 2+, 2.1.1 is current I believe). Here's an example impl, based on: https://github.com/hibernate/hibernate-validator/blob/master/cdi/src/main/java/org/hibernate/validator/internal/cdi/InjectingConstraintValidatorFactory.java
public class InjectingConstraintValidatorFactory implements ConstraintValidatorFactory {
// TODO look for something with better performance (HF)
private final Map<Object, DestructibleBeanInstance<?>> constraintValidatorMap =
Collections.synchronizedMap( new IdentityHashMap<Object, DestructibleBeanInstance<?>>() );
private final BeanManager beanManager;
public InjectingConstraintValidatorFactory() {
this.beanManager = CDI.current().getBeanManager();
Contracts.assertNotNull( this.beanManager, "The BeanManager cannot be null" );
}
#Override
public <T extends ConstraintValidator<?, ?>> T getInstance(Class<T> key) {
DestructibleBeanInstance<T> destructibleBeanInstance = new DestructibleBeanInstance<T>( beanManager, key );
constraintValidatorMap.put( destructibleBeanInstance.getInstance(), destructibleBeanInstance );
return destructibleBeanInstance.getInstance();
}
#Override
public void releaseInstance(ConstraintValidator<?, ?> instance) {
DestructibleBeanInstance<?> destructibleBeanInstance = constraintValidatorMap.remove( instance );
destructibleBeanInstance.destroy();
}
}
I finally fixed this. Turns out, a validation.xml is not really required, resteasy-cdi module does a fine job of registering the BeanManager. What I was missing and not clearly documented anywhere, is that if an annotation is placed on a method, the validation engine just "decides" what should be validated. I placed a #NotNull on a method and it was validating the return type, not the parameters. One can use validationAppliesTo element in some cases but #NotNull doesn't have it. When I moved it from the method to the parameter, it started working.
Now I ran across what I believe is a Weld bug but I'll post that question separately.

CDI extension, altering processed type

Using Weld 1.1.13.Final in test with Arquillian....
Let's say I inject into a field something volatile. Something like a property subject to change that I want the bean owning the injection point to receive change events. Thought about creating a CDI extension.
Caught ProcessAnnotatedType event and looking for all fields that have an custom annotation on field injection points:
<T> void pat(#Observes ProcessAnnotatedType<T> event, BeanManager bm) {
final AnnotatedType<T> target = event.getAnnotatedType();
for (AnnotatedField<? super T> field : target.getFields())
if (field.isAnnotationPresent(Value.class)) { // ignore that I don't check #Inject here for the moment
CtClass wrapper = pool.get(target.getJavaClass().getName());
ConstPool cp = wrapper.getClassFile().getConstPool();
CtMethod m = CtNewMethod.make(....)
....
wrapper.addMethod(m);
event.setAnnotatedType(bm.createAnnotatedType(wrapper.toClass()));
}
}
Had even grabbed thereafter all the injection points for fields and replaced the underlying WeldField with a new Field corresponding the "wrapper" type. Otherwise bean validation fails.
But this only works for stuff setup during startup not when for example Arquillian uses the Bean Manager to initialize a class that injects one of my "wraps". Things fail since the Bean Resolver uses the Type as a hash key to find beans.
Basically I don't think I can "mask" a class that is annotated (made into a bean) by the CDI with an extra method to receive custom events. Would have been cool but a Type is a Type (i.e. no idea how to proxy or fake the equals/hashCode).
Got it. Turns out the compute value function (google extension) inside the TypeSafeBeanResolver resolver (at least the CDI Weld implementation) is smart. If I just extend the class:
CtClass wrapper = pool.makeClass(target.getJavaClass().getName()+"Proxy");
wrapper.setSuperclass(pool.get(target.getJavaClass().getName()));
.....
final AnnotatedType<T> other = bm.createAnnotatedType(wrapper
.toClass());
then everything works fine. Tested capturing an event in a bean. Will post the code on a Gist with a comment.

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