如何使用CDI构建插件架构 - 我正在使用Wildfly 10 [英] How to build a plugin architecture using CDI - I'm using Wildfly 10
问题描述
我想构建一个基于JEE插件的架构。主要的想法是做类似于eclipse的东西，但是在JEE的背景下。
我的目标是以最少的模块为核心，并允许其他模块扩展其功能。
为此，我使用了4个模块实现了测试：
I want to build a JEE plugin based architecture. The main idea is do something similar to what eclipse is, but in the context of JEE. My goal is to have a minimum of modules as the core, and allow others modules extend its functionality. To this, I have implemented a test using 4 modules:
gauges: Defines and implements a gaugesregistry service, also defines a gauge POJO.
cashgauges: implements a gauge producer using CDI. this is a plugin mock.
othergauges: implements a gauge producer using CDI. this is a second plugin mock.
gauges-web: Contains a basic JSF view to query the gauges registry.
依赖关系如下：
cashgauges --> gauges
othergauges --> gauges
gauges-web --> gauges
这是通过使用 jboss-deployment-structure.xml 。
部署是作为单个文件完成的：
The deployment is done as individual files:
gauges.jar
cashgauges.jar
othergauges.jar
gauges-web.war
所有服务都开始了，但我看到的是，我的 gaugesregistry 被多次实例化。我在调试模式下启动了wildfly，我看到每个模块都有自己的gaugesregistry实例：cashgauges和othergauges在注册表上调用相同的方法（ addGauge ），但是这个注册表的实例不一样。
All services start, but what I see is, my gaugesregistry is instantiated several times. I started wildfly in debug mode and what I see is each module has its own instance of gaugesregistry: cashgauges and othergauges call same method (addGauge) on registry, but instances of this registry are not the same.
在这两种情况下都会发生这种情况，使用 @ApplicationScoped 和 @单身人士注释。我做错了什么？
This happens in both cases, using @ApplicationScoped and @Singleton annotations. What am I doing wrong?
源代码可在上找到https://github.com/hatit/research
几天后，我正在考虑使用ServiceLocator模式和远程引用而不是CDI 。有什么建议吗？
After a couple of days, I'm considering using a ServiceLocator pattern and remote references instead of CDI. Any suggestions?
推荐答案
太棒了，我得到了两次-2票（-4点声），因为我问过软件开发人员的高级主题？
Great, i got twice -2 votes (-4 reputation) because i asked an advanced topic for software developers?
我搜索了一下stackoverflow，发现了这个
I searched in about stackoverflow and found this
成立于2008年，Stack溢出是最大，最值得信赖的在线社区，供开发人员学习，分享知识，建立自己的职业......
Founded in 2008, Stack Overflow is the largest, most trusted online community for developers to learn, share their knowledge, and build their careers...
如果有的话那么对这个主题感兴趣：
If any interested in this topic, then:
在用作独立模块（JBoss模块）后，了解CDI Beans和EJB生命周期之间的差异几个小时后，我发现：
After some hours understanding differences between CDI Beans and EJBs lifecycle when used as independent modules (JBoss Modules), i found:
Singleton CDI Beans每个模块实例化一次，而不是所有模块中的单独实例。
Singleton CDI Beans are instantiated one time per module, not really singleton among all modules.
为了避免这种情况，我必须创建注册表作为Singleton企业会话Bean。
这带来了新的问题，CDI注入在模块之间不起作用，所以我不得不打包一个CDI生产者（我不在乎它是否是单身，它只是一个生产者），它可以被任何实例化模块。这个生产者的主要职责是查找Registry EJB，这样可以避免每次需要访问Registry时硬编码jndi路径。
To avoid this i had to create Registry as a Singleton Enterprise Session Bean. This cames with new problems, CDI injection doesn't works among modules, so i had to package a CDI producer (i don't care if it's singleton or not, its only a producer) which can be instantiated by any module. Main responsibility of this producer is to lookup Registry EJB, this to avoid hardcoding jndi path each time i need access the Registry.
我改变了我的简单示例以支持JSF插件，这是我目前使用的一个例子。
I changed my trivial example to support JSF plugins also, this is an example of what i am using currently.
模块facelets：
Module facelets:
注册表界面：
public interface FaceletsModuleRegistry {
void registerModule(String module);
List<String> getRegisteredModules();
}
注册表实施：
@Local(FaceletsModuleRegistry.class)
@Singleton(name="FaceletsModuleRegistry")
@TransactionAttribute(TransactionAttributeType.NOT_SUPPORTED)
@Vetoed
public class FaceletsModuleRegistryImpl implements FaceletsModuleRegistry {
private Set<String> registeredModuleNames = new TreeSet<>();
@Override
public void registerModule(String module) {
registeredModuleNames.add(module);
}
@Override
public List<String> getRegisteredModules() {
return Collections.unmodifiableList(new ArrayList<>(registeredModuleNames));
}
}
注册管理机构制作人：
@ApplicationScoped
public class FaceletsModuleRegistryBuilder {
@EJB(lookup="java:global/facelets/FaceletsModuleRegistry!co.hatit.enterprise.facelets.services.FaceletsModuleRegistry")
protected FaceletsModuleRegistry faceletsModuleRegistry;
@Produces
public FaceletsModuleRegistry getFaceletsModuleRegistry(){
return faceletsModuleRegistry;
}
}
我想插件的任何其他模块都会实现此代码（请参阅 @Inject 可用于任何需要访问Registry单例实例的模块）：
Any other module that i want to plugin implements this code (please see @Inject can be used on any module requiring access the Registry singleton instance):
@ApplicationScoped
public class InmueblesActivator {
@Inject
private FaceletsModuleRegistry faceletsModuleRegistry;
public void init(@Observes @Initialized(ApplicationScoped.class) Object init){
String moduleName = Module.getCallerModule().getIdentifier().getName();
String name = StringUtils.substringBetween(moduleName, "deployment.", ".jar");
faceletsModuleRegistry.registerModule(name);
}
}
然后我可以从任何地方引用注册表模块作为一个真正的单例实例（解决了我的问题，当在几个模块中使用CDI单例bean时，有多个相同类的实例）。
Then i can reference Registry from any module as a really singleton instance (solved my problem having multiple instances of same class when used CDI singleton beans among several modules).
现在，我可以插入JEE模块，而不是只是java代码，但facelets资源也是：
Now, i can plugin JEE modules, not just java code, but facelets resources also:
public class FaceletsResourceHandler extends ResourceHandlerWrapper {
Logger logger = LoggerFactory.getLogger(FaceletsResourceHandler.class);
@Inject
FaceletsModuleRegistry faceletsModuleRegistry;
private ResourceHandler wrapped;
public FaceletsResourceHandler(ResourceHandler wrapped) {
this.wrapped = wrapped;
}
@Override
public ViewResource createViewResource(FacesContext context, final String name) {
ViewResource resource = super.createViewResource(context, name);
if (resource == null) {
resource = new ViewResource() {
@Override
public URL getURL() {
try {
//iterates over plugins to find the required resource.
for(String module : faceletsModuleRegistry.getRegisteredModules()){
URL resource = Module.getCallerModule().getModuleLoader()
.loadModule(ModuleIdentifier.create("deployment." + module + ".jar"))
.getExportedResource("META-INF/resources" + name);
if (resource != null) return resource;
}
} catch (ModuleLoadException e) {
throw new FacesException(e);
}
return null;
}
};
}
return resource;
}
@Override
public ResourceHandler getWrapped() {
return wrapped;
}
}
这篇关于如何使用CDI构建插件架构 - 我正在使用Wildfly 10的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
