OSGi - 服务实现是否可以使用其他服务？

程序员大家好，

我最近开始研究OSGi项目 . 我试图使用Declarative Services来习惯OSGi服务 . 我创建了一个接口包（A），一个实现此接口的包（B）和一个使用该服务的包（C） . 到现在为止还挺好 . 但是当我尝试创建一个实现另一个接口（D）的包时，我发现我无法使用bundle（A）提供的服务 .

所以我有4个捆绑：

• 捆绑A：API

• Bundle B：Bundle实现A

• 捆绑D：实现E

• 捆绑E：另一个api捆绑

为什么我不能从捆绑B中消费服务E？

Bundle A

package liqueurplant.osgi.silo.driver.api;

import org.osgi.annotation.versioning.ProviderType;

@ProviderType
public interface SiloDriverIf {

void openDriver();

void closeDriver();
}

Bundle B

package liqueurplant.osgi.silo.driver;

import liqueurplant.osgi.silo.controller.api.SiloCtrlIf;
import liqueurplant.osgi.silo.driver.api.SiloDriverIf;
import org.osgi.service.component.annotations.*;

@Component
public class SimpleSiloDriver implements SiloDriverIf {

private SiloCtrlIf siloCtrl;

@Activate
public void activate() {
    System.out.println("Driver activated.");
}

@Deactivate
public void deactivate() {
    siloCtrl.put2EventQueue("High lever reached");
}

@Override
public void openDriver() {

}

@Override
public void closeDriver() {

}

@Reference(
        name = "siloCtrl.service",
        service = SiloCtrlIf.class,
        /* Cardinality (Whether the bundle works with or without service.
        // Mandatory: mandatory and unary 1..1
        // At least one: mandatory and multiple 1..n
        // Multiple: optional and multiple 0..n
        // Optional: optional and unary 0..1
        //*/
        cardinality = ReferenceCardinality.MANDATORY,
        policy = ReferencePolicy.DYNAMIC,
        unbind = "unsetSiloCtrlIf"
)
protected void setSiloCtrlIf(SiloCtrlIf siloCtrl){
    System.out.println("Binding silo controller service");
    this.siloCtrl = siloCtrl;
}

protected void unsetSiloCtrlIf(SiloCtrlIf siloCtrl){
    System.out.println("Unbinding silo controller service.");
    this.siloCtrl = null;
}
}

Bundle D

package liqueurplant.osgi.silo.controller;

import liqueurplant.osgi.silo.controller.api.SiloCtrlIf;
import org.osgi.service.component.annotations.*;

import java.util.concurrent.ArrayBlockingQueue;

@Component
public class SimpleSiloCtrl implements SiloCtrlIf, Runnable {

private ArrayBlockingQueue<String> eventQueue;

public SimpleSiloCtrl() {
    eventQueue = new ArrayBlockingQueue<String>(20);
}

@Activate
public void activate() {
    System.out.println("Silo controller activated.");
}

@Override
public void put2EventQueue(String event) {
    try {
        eventQueue.put(event);
        System.out.println(eventQueue.take());
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
}

@Override
public void run() {
    while(true){
        if(!eventQueue.isEmpty()){
            try {
                System.out.println(eventQueue.take());
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}


}

Bundle E

package liqueurplant.osgi.silo.controller.api;

import org.osgi.annotation.versioning.ProviderType;

@ProviderType
public interface SiloCtrlIf {

    void put2EventQueue(String event);
}

当我尝试运行代码时，Bundle B上的@Activate方法不起作用，而且服务siloCtrl.service没有绑定 . 任何帮助，将不胜感激 . 先感谢您！