OSGi如何运行一项服务的多个实例 [英] OSGi how to run mutliple instances of one service

问题描述

是否可以在osgi框架中运行同一服务的多个实例? 更具体地说，我需要启动一个服务的多个实例，但是每个实例应接收不同的参数.这是因为服务具有相似的功能.但是，我不想为每个变体编写服务，而是要重用一个实现类.

Is it possible to run multiple instance of the same service in the osgi framework? More specific, I need to start multiple instances of a service, but each instance should recieve different parameters. This is because the services have similar functionality. But instead of writing a service for every variation, I want to reuse one implementing class.

我已经在框架api中找到了registerService方法.

I've already found the registerService method in the framework api.

    ServiceRegistration<?> registration = bundlecontext.registerService(
            className, class, null);

但是，我似乎只为每个类创建一个实例.有解决方法吗?

however, i seem to create only one instance of each class. Is there a workaround for this?

最好是类似

    ServiceRegistration<?> registration = bundlecontext.registerService(
            className + "#" + (++counter), new classInstance(), null);

推荐答案

请注意，将声明式服务与相应的注释配合使用非常容易，这是Apache Sling代码库的摘录(

Note that using Declarative Services with the corresponding annotations makes this quite easy, here's an excerpt from the Apache Sling codebase (ConfiguredFeature.java):

@Component(
        name = "org.apache.sling.featureflags.Feature",
        metatype = true,
        configurationFactory = true,
        policy = ConfigurationPolicy.REQUIRE)
@Service
public class ConfiguredFeature implements Feature {

    @Property(label = "Name", description = "Short name of this feature")
    private static final String NAME = "name";

    private String name;

    @Activate
    private void activate(final Map<String, Object> configuration) {
        this.name = PropertiesUtil.toString(configuration.get(NAME), "");
    }

    ...
}

使用configurationFactory = true和policy = ConfigurationPolicy.REQUIRE会为每个对应的OSGi配置创建此服务的一个实例，这是创建多个实例的自然方法.

Using configurationFactory = true and policy = ConfigurationPolicy.REQUIRE causes one instance of this service to be created for each corresponding OSGi configuration, which is a natural way of creating multiple instances.

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