com.sun.hk2.component.InjectionResolver Maven / Gradle / Ivy
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package com.sun.hk2.component;
import org.jvnet.hk2.component.ComponentException;
import org.jvnet.hk2.component.Inhabitant;
import java.lang.annotation.Annotation;
import java.lang.reflect.AnnotatedElement;
import java.lang.reflect.Method;
import java.lang.reflect.Type;
/**
* Implementation of this abstract class are handling injection resolution
* for a particular injection annotation {@see Inject}
*
* Injection targets are identified by the generic parameter and the constructor
* of this class. Potential injection targets are fields and methods of the
* injected type.
*
* @param U is the annotation used to identify the injection targets.
*
* @author Jerome Dochez
*/
public abstract class InjectionResolver {
public final Class type;
/**
* Construct a resolver with a particular injection type
* @param type the injection annotation type
*/
public InjectionResolver(Class type) {
this.type = type;
}
/**
* Returns the setter method responsible for setting the resource identified by the
* passed annotation on the passed annotated method.
*
* This is useful when the annotation is specified on the getter for instance (due
* to external specification requirements for instance) while the setter should be used if
* values must be set using this injection resolver.
*
* By default, the setter method is the annotated method.
*
* @param annotated is the annotated {@link java.lang.reflect.Method}
* @param annotation the annotation on the method
* @return the setter method to use for injecting the annotation identified resource
*/
public Method getSetterMethod(Method annotated, U annotation) {
return annotated;
}
/**
* Returns true if the resolution of this injection identified by the
* passed annotation instance is optional
* @param annotated is the annotated java element {@link java.lang.reflect.Method}
* or {@link java.lang.reflect.Field}
* @param annotation the injection metadata
* @return true if the {@see getValue()} can return null without generating a
* faulty injection operation
*/
public boolean isOptional(AnnotatedElement annotated, U annotation) {
return false;
}
/**
* Returns the value to inject in the field or method of component annotated with
* the annotated annotation.
*
// * @param habitat the habitat containing component / inhabitant
* @param component injection target instance
* @param onBehalfOf inhabitant doing the injection for
* @param annotated is the annotated java element {@link java.lang.reflect.Method}
* or {@link java.lang.reflect.Field}
* @param genericType the generic type of the expected return
* @param type type of the expected return
* @return the resource to be injected
* @throws ComponentException if the resource cannot be located.
*/
public abstract V getValue(Object component,
Inhabitant onBehalfOf,
AnnotatedElement annotated,
Type genericType,
Class type) throws ComponentException;
}