如何在当前视图（范围）中找到/的CDI bean？ [英] How do you find CDI beans of/in the current view (scope)?

问题描述

在 Java EE 6，CDI 1.1.x，Seam 3等环境中，我们需要查找当前视图的所有CDI bean（ @ViewScoped ）。我到目前为止尝试使用的是：

In a Java EE 6, CDI 1.1.x, Seam 3 etc. environment, we need to find all CDI beans of the current view (@ViewScoped). What I have tried so far is using:

@Named
@ViewScoped
public class ViewHelper
{
    @Inject
    private BeanManager beanManager;

    public doSomethingWithTheBeanInstances()
    {
        Set<Bean<?>> beans = this.getBeanManager().getBeans( 
            Object.class, new AnnotationLiteral<Any>(){}
        );

        // do something
        ...
    }
}

然而，这会返回它管理的所有 bean。

However, this returns all beans it manages.

我只需找到那些中的当前视图的范围和 - 这将是理想的 - 只有那些实现特定接口（通过多个层次结构级别继承）。

I need to find only those within the scope of the current view and - that would be ideal - only those that implement a specific interface (inherited over over multiple hierarchy levels).

这是什么方式要做吗？

注意，由于CDI没有视图范围，我们使用 Seam 3 来注释我们所有的视图范围bean如：

Note since CDI has no view scope, we're using Seam 3 to be able to annotate all our view-scoped beans like:

@Named
@ViewScoped
public class ResultManagerColumnHandler extends BaseColumnHandler
{
    ....
}

以上是寻找的实例（ @ViewScoped 是Seam 3的CDI替代品。）

The above would be an instance to look for (the @ViewScoped is a CDI replacement by Seam 3).

怎么办？

推荐答案

我不熟悉Seam，但来自CDI标准t，这就是我想要的。但是，请注意，如果 beanManager.getContext（ViewScoped.class）; 为您返回一个有效的上下文实例> ：

I am not familiar with Seam, but from CDI standpoint, this is what I would try. However, bean it mind that it will only work if beanManager.getContext(ViewScoped.class); returns a valid context instance for you:

@Inject
BeanManager bm;

public List<Object> getAllViewScoped() {
    List<Object> allBeans = new ArrayList<Object>();
    Set<Bean<?>> beans = bm.getBeans(Object.class);
    // NOTE - context has to be active when you try this
    Context context = bm.getContext(ViewScoped.class);

    for (Bean<?> bean : beans) {
        Object instance = context.get(bean);
        if (instance != null) {
            allBeans.add(instance);
        }
    }

    return allBeans;
}

您还要求只获取实现特定接口的bean。为此，只需修改代码行，检索所需类型的所有bean：

You also asked to only obtain beans that implement certain interface. For that, simply modify the code line retrieving all beans with desired type:

Set<Bean<?>> beans = bm.getBeans(MyInterface.class);

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