如何确保OSGi包以正确的顺序加载

Question

我有一个以编程方式启动OSGi容器的类,加载bundle,然后启动它们.我遇到的问题是捆绑包没有按正确的顺序启动.一些bundle在依赖于它们开始之前加载并启动.

如何确保所有捆绑包以正确的顺序开始,而不是在它们依赖的那些之前？

PS: 到目前为止我所建议的任何代码改进都是受欢迎的.

谢谢大家.

import java.io.File;
import java.net.URISyntaxException;
import java.net.URL;
import java.util.HashMap;
import java.util.Map;
import java.util.ServiceLoader;

import org.osgi.framework.Bundle;
import org.osgi.framework.BundleException;
import org.osgi.framework.Constants;
import org.osgi.framework.ServiceReference;
import org.osgi.framework.launch.Framework;
import org.osgi.framework.launch.FrameworkFactory;

public class App {

    public static void main(String[] args) throws BundleException, URISyntaxException {
        App app = new App();
        app.initialize();
    }

    private void initialize() throws BundleException, URISyntaxException {
        Map<String, String> map = new HashMap<String, String>();

        // make sure the cache is cleaned
        map.put(Constants.FRAMEWORK_STORAGE_CLEAN, Constants.FRAMEWORK_STORAGE_CLEAN_ONFIRSTINIT);

        map.put("ds.showtrace", "true");
        map.put("ds.showerrors", "true");

        FrameworkFactory frameworkFactory = ServiceLoader.load(FrameworkFactory.class).iterator().next();
        Framework framework = frameworkFactory.newFramework(map);

        System.out.println("Starting OSGi Framework");
        framework.init();

        File baseDir = new File("target/dist-1.0-SNAPSHOT-bin/plugins/");

        loadScrBundle(framework);

        // get all the Bundles from our plugins directory
        File[] fList = baseDir.listFiles();

        for (File file : fList) {
            if (file.isFile()) {
                System.out.println(file.getAbsolutePath());

                if (file.getName().endsWith(".jar")) {
                    framework.getBundleContext().installBundle(file.toURI().toString());
                }
            } else if (file.isDirectory()) {
                // recurse
            }
        }

        for (Bundle bundle : framework.getBundleContext().getBundles()) {
            bundle.start();
            System.out.println("Bundle: " + bundle.getSymbolicName());
            if (bundle.getRegisteredServices() != null) {
                for (ServiceReference<?> serviceReference : bundle.getRegisteredServices())
                    System.out.println("\tRegistered service: " + serviceReference);
            }
        }
    }

    private void loadScrBundle(Framework framework) throws URISyntaxException, BundleException {
        URL url = getClass().getClassLoader().getResource("org/apache/felix/scr/ScrService.class");
        if (url == null)
            throw new RuntimeException("Could not find the class org.apache.felix.scr.ScrService");
        String jarPath = url.toURI().getSchemeSpecificPart().replaceAll("!.*", "");
        System.out.println("Found declarative services implementation: " + jarPath);
        framework.getBundleContext().installBundle(jarPath).start();
    }
}

Answer 1

如果你写的是依赖于启动顺序OSGi的代码,那么你没有一个OSGi代码...任何人我知道,在过去的18年里试图与开始以淤泥有很多的使用OSGi预防的问题.因为在OSGi中,任何捆绑包都可以随时启动/停止,您可以在启动时使其工作一次,但任何干扰都会导致代码中断.

如果您使用OSGi声明式服务,那么这些问题就不存在了.只需将任何时间依赖关系转换为服务并依赖于该服务.

真的,克服它,OSGi没有订购......