That sounds good Matt, I say go for it. Gary
On Tue, Oct 8, 2019, 16:08 Matt Sicker <boa...@gmail.com> wrote: > I've been doing some experiments with the plugin system for 3.x > lately, and I've recently pushed some changes toward that end. One of > the insights I gained from it was that some of our plugin annotations > were redundant (result: @PluginBuilderFactory merged into > @PluginFactory; @PluginBuilderAttribute deprecated for merging into > @PluginAttribute). After making those changes, I realized that @Plugin > and @PluginFactory didn't necessarily need to be separate annotations, > though I hadn't written any code to try that out yet. However, I did > realize over time that I was essentially reinventing a mini dependency > injection framework (hence the historical references to Spring and > Java EE concepts in the code or comments). In that regard, I > identified that all the current plugin annotations can be categorized > as follows: > > * @Plugin - essentially identifies an injectable class and its name. > * @PluginAliases - alternative names for annotated elements > * @PluginFactory - marks the injection point for a plugin > * @PluginElement, @PluginNode, @PluginConfiguration - all type-based > dependency injection corresponding to other plugins (seems to apply > regardless of the element name as well) > * @PluginAttribute, @PluginValue, etc. - all name-based configuration > injection > > What I'd like to propose is a vast simplification of this system to > reuse the javax.inject API [1] since we've already split out > log4j-plugins into its own dependency. As you can see, it's a fairly > small package, though we could potentially reuse the API without the > package names, too. A general conversion of API usage would work like > such: > > * @Plugin name can be replaced by @Named annotation > * Aliases can still be specified by a separate annotation > * @PluginElement can be a specific @Scope annotation and generally > rely on @Inject > * @PluginFactory can be replaced by @Inject > * Builder<T> can be replaced by Provider<T> > * @PluginAttribute can be replaced by @Named @Inject of simple types > as well as maybe @Qualifier in general > > I can work on a PoC for this, though I wanted to see if this idea was > acceptable here. I don't want to introduce a full blown dependency > injection framework like Guice/Spring/CDI/etc. since all we need is a > way to bind configurations to a specific object graph, though the ad > hoc nature of plugins in the past has made some things harder to keep > a stable API for, and I think this could help improve that situation. > > By going with the standardized annotations, we might also be able to > take advantage of other tooling for generating static representations > of a configuration for AOT compilation in microservices or other neat > things. > > [1]: > https://docs.oracle.com/javaee/7/api/javax/inject/package-summary.html > > -- > Matt Sicker <boa...@gmail.com> >
