java - 如何启动 immediate = false 组件？

Question

我有以下组件:

@Component(
    label = "Service name",
    description = "Service description",
    metatype = true,
    immediate = false)
@Properties({
    @Property(
            label = "My Label"
            name = "property-name",
            value = "my value",
            propertyPrivate = true
    )
})
@Service
public class SampleServiceImpl implements SampleService {
    private final Logger log = 
        LoggerFactory.getLogger(this.getClass());

    /**
     * OSGi Properties *
     */
    private static final String DEFAULT_SAMPLE = "hello!";
    private String mySample = DEFAULT_SAMPLE;
    @Property(label = "Prop name", 
              description = "Prop description", 
              value = DEFAULT_SAMPLE)
    public static final String PROP_SAMPLE = "sample";

    ...

    @Activate
    protected void activate(final Map<String, String> config) { 
        mySample = PropertiesUtil.toString(config.get(PROP_SAMPLE), DEFAULT_SAMPLE);
    }

    @Deactivate
    protected void deactivate(final Map<String, String> config) { }
}

是在cq启动后注册的。这是预期的行为。

如何开始？我找不到这个界面。

Answer 1

是的，这是非直接组件的预期行为。来自 a blog post作者:Felix Meschberger 在 dev.day.com 上，

The OSGi Declarative services specification defines three types of components:

• Immediate Components are immediately created when the providing bundle is started and may or may not provide services

• Delayed Components provide services but are only created when used by a service consumer.

• Factory Components are created on demand by calling the ComponentFactory.newInstance(Dictionary) method of the Component Factory service registered for the component.

因此，如果您设置 immediate = false，您将拥有一个延迟组件，它由运行时按需激活 — 您不需要自己显式启动该组件。

您应该检查的主要内容是组件处于“已启用”或“已注册”状态(正如您提到的那样)而不是“不满意”(它找不到对它需要的依赖项)。

From the Felix documentation ……

STATE_REGISTERED

The Component has successfully been activated but is a Delayed or Service Factory Component pending instantiation on first use (value is 32).