[cdi-dev] [JBoss JIRA] (CDI-484) Provide forwarding implementations of SPI interfaces

Provide forwarding implementations of SPI interfaces ---------------------------------------------------- Key: CDI-484 URL: https://issues.jboss.org/browse/CDI-484 Project: CDI Specification Issues Issue Type: Feature Request Components: Portable Extensions Affects Versions: 1.2.Final Reporter: Jozef Hartinger Fix For: 2.0 (discussion) The decorator design pattern is commonly used in CDI extensions to modify existing metadata by wrapping it with a wrapper implementation that overrides certain method. This can be done in the following callbacks: ProcessAnnotatedType, ProcessProducer, ProcessInjectionTarget, ProcessInjectionPoint and ProcessBeanAttributes. In order to do this it is often very convenient to have a forwarding implementation available, e.g.: {code:JAVA} void wrap(@Observes ProcessAnnotatedType<Foo> event) { final AnnotatedType<Foo> delegate = event.getAnnotatedType(); event.setAnnotatedType(new ForwardingAnnotatedType<Foo>(delegate) { @Override public <A extends Annotation> A getAnnotation(Class<A> annotationType) { return null; } @Override public Set<Annotation> getAnnotations() { return Collections.emptySet(); } @Override public boolean isAnnotationPresent(Class<? extends Annotation> annotationType) { return false; } } {code} We should consider providing these utility forwarding implementations as part of the CDI API. This is similar to e.g. Servlet specification doing this for their decorable APIs (http://tomcat.apache.org/tomcat-5.5-doc/servletapi/javax/servlet/http/Htt...)