[cdi-dev] [JBoss JIRA] Issue Comment Edited: (CDI-127) Add support for annotation scanning of Java enums

[ https://issues.jboss.org/browse/CDI-127?page=com.atlassian.jira.plugin.sy... ] Pete Muir edited comment on CDI-127 at 6/21/11 9:16 AM: -------------------------------------------------------- h1. Notes Enums are somewhat different to normal classes, as Java guarantees that any instances are singletons. Therefore we cannot treat them as classes. Furthermore, do we want to support them as beans, allowing them to be injected? Differences are: * No callback on instantiation, when do we inject? * Shared between deployments as singletons, how do we handle dependent scoped injections? * We do not control instantiation, cannot perform constructor injection h1. Proposal We should support enums as non-contextual objects, performing field and method injection only. Enums should be assumed to be injected only after the application is fully initialized for portability. If an enum is on a shared classloader, any injections should correctly resolve to the deployment of the calling context. In other words, if a shared library or installed library has an enum A: {code} enum A { FOO, BAR; @Inject B b; String getName() { return b.name; } } {code} where B is a class defined in the shared library {code} @ApplicationScoped class B { String name; } {code} Then assuming that the name has been set to Pete in deployment 1, and Marius in deployment 2, when the enum A is used in deployment 1, the method getName() should return Pete, and in deployment 2 it should return Marius. was (Author: petemuir): h1. Notes Enums are somewhat different to normal classes, as Java guarantees that any instances are singletons. Therefore we cannot treat them as classes. Furthermore, do we want to support them as beans, allowing them to be injected? Differences are: * No callback on instantiation, when do we inject? * Shared between deployments as singletons, how do we handle dependent scoped injections? * We do not control instantiation, cannot perform constructor injection h1. Proposal We should support enums as non-contextual objects, performing field injection only. Enums should be assumed to be injected only after the application is fully initialized for portability. If an enum is on a shared classloader, any injections should correctly resolve to the deployment of the calling context. In other words, if a shared library or installed library has an enum A: {code} enum A { FOO, BAR; @Inject B b; String getName() { return b.name; } } {code} where B is a class defined in the shared library {code} @ApplicationScoped class B { String name; } {code} Then assuming that the name has been set to Pete in deployment 1, and Marius in deployment 2, when the enum A is used in deployment 1, the method getName() should return Pete, and in deployment 2 it should return Marius. -- This message is automatically generated by JIRA. For more information on JIRA, see: http://www.atlassian.com/software/jira