package org.jboss.seam.solder.bean;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
import java.util.Set;
import javax.enterprise.context.spi.CreationalContext;
import javax.enterprise.inject.spi.Bean;
import org.jboss.seam.solder.reflection.Reflections;
/**
* <p>
* A narrowing bean allows you to build a general purpose bean (likely a
* producer method), and register it for a narrowed type (or qualifiers). For
* example, you could create a producer method which uses an a String ID to
* located an object (the object can have any class):
* </p>
*
* <pre>
* @Produces
* // Use some synthetic scope to prevent this from interfering with other
* // resolutions
* @MyProducer
* Object produce(InjectionPoint ip)
* {
* String id = ip.getAnnotated().getAnnotation(Id.class).value();
* // Lookup and return the object for the id
* }
* </pre>
*
* <p>
* The delegate bean <em>must</em> return an object which can be cast to the
* type <code>T</code>, otherwise a {@link ClassCastException} will be thrown at
* runtime when the bean is created.
* </p>
*
* <p>
* You can then register a narrowing bean for each type you need:
* </p>
*
* <pre>
* event.addBean(new NarrowingBeanBuilder<T>(delegateBean).readFromType(type).create());
* </pre>
*
* <p>
* {@link ImmutableNarrowingBean} will use the annotations on
* <code>defininingType</code> to discover the qualifiers, types, scope,
* stereotypes of the bean, as well as determine it's name (if any) and whether
* it is an alternative.
* </p>
*
* <p>
* The attributes are immutable, and collections are defensively copied on
* instantiation. It uses the defaults from the specification for properties if
* not specified.
* </p>
*
* @author Pete Muir
* @see NarrowingBeanBuilder
* @see ImmutablePassivationCapableNarrowingBean
*/
public class ImmutableNarrowingBean<T> extends AbstractImmutableBean<T>
{
private final Bean<Object> delegate;
/**
* Instantiate a new {@link ImmutableNarrowingBean}.
*
* @param delegate the bean to delegate the lifecycle to
* @param name the name of the bean
* @param qualifiers the qualifiers of the bean
* @param scope the scope of the bean
* @param stereotypes the bean's stereotypes
* @param types the types of the bean
* @param alternative whether the bean is an alternative
*/
public ImmutableNarrowingBean(Bean<Object> delegate, String name, Set<Annotation> qualifiers, Class<? extends Annotation> scope, Set<Class<? extends Annotation>> stereotypes, Set<Type> types, boolean alternative, boolean nullable, String toString)
{
super(delegate.getBeanClass(), name, qualifiers, scope, stereotypes, types, alternative, nullable, delegate.getInjectionPoints(), toString);
this.delegate = delegate;
}
public T create(CreationalContext<T> creationalContext)
{
return Reflections.<T> cast(delegate.create(Reflections.<CreationalContext<Object>> cast(creationalContext)));
}
public void destroy(T instance, CreationalContext<T> creationalContext)
{
delegate.destroy(instance, Reflections.<CreationalContext<Object>> cast(creationalContext));
}
}