org.glassfish.hk2.api.JustInTimeInjectionResolver Maven / Gradle / Ivy
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package org.glassfish.hk2.api;
import org.jvnet.hk2.annotations.Contract;
/**
* The JustInTimeInjectionResolver is called when an injection point
* cannot find anything to inject. It allows a third party systems
* to dynamically add descriptors to the system whenever
* an injection point would have failed to resolve (or an Optional
* injection point found no service definitions).
*
* All injection resolvers registered with the system will be called
* in a random order. Resolvers should therefore not rely on the ordering
* of installed injection resolvers. Any injection resolvers added as a
* result of this callback will NOT be called until the next injection
* resolution failure.
*
* Implementations of this interface are placed into the registry like
* any other service. One use-case would be to inject the
* {@link DynamicConfigurationService} into the implementation in order
* to add services if this resolver can do so. Another option would
* be to inject a {@link ServiceLocator} and use one of the methods
* in {@link org.glassfish.hk2.utilities.ServiceLocatorUtilities} in order
* to add services to the registry
*
* If any of the registered injection resolvers commits a dynamic change
* then the system will try one more time to resolve the injection before
* failing (or returning null if the injection point is Optional).
*
* @author jwells
*/
@Contract
public interface JustInTimeInjectionResolver {
/**
* This method will be called whenever an injection point cannot be resolved. If this
* method adds anything to the configuration it should return true. Otherwise it
* should return false. The injection point that failed to be resolved is given
* in failedInjectionPoint.
*
* If this method throws an exception that exception will be added to the set of
* exceptions in the MultiException that may be thrown from the injection resolver
*
* @param failedInjectionPoint The injection point that failed to resolve
* @return true if this method has added a descriptor to the {@link ServiceLocator}
* which may be used to resolve the {@link Injectee}. False if this method
* did not add a descriptor to the {@link ServiceLocator} that might help
* resolve the injection point
*/
public boolean justInTimeResolution(Injectee failedInjectionPoint);
}