如何正确启动和关闭OSGi容器？

Question

I have made a bundle which has an Activator file that basically launches other bundles by their correct order. I needed this because the framework would start some bundles before their dependencies have finished starting. For example my bundles depending on my log service would start before it, so log messages would not be stored for those bundles. With this Activator I can choose who starts first, since there is no clear way to do it in felix .

The code for this is here:

package lumina.launcher;

import java.io.File;
import java.util.ArrayList;
import java.util.List;

import org.osgi.framework.Bundle;
import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;
import org.osgi.framework.BundleException;

public final class Launcher implements BundleActivator {

    private BundleContext context;

    private final String relativePath = "./bundle/";

    private final void print(String msg) {
        // System.out.println(msg);
    }

    private Bundle install(String path) throws BundleException {
        Bundle bundle = this.context.installBundle("file:/" + path);
        print("\tInstalling: " + bundle.getSymbolicName());
        return bundle;
    }

    private boolean isJar(String fileName) {
        final String[] tokens = fileName.split("\\.");
        return tokens.length != 0 && "jar".equals(tokens[tokens.length - 1]);
    }

    private String[] listFilesForFolder(final File folder)
            throws BundleException {
        final List<String> bundles = new ArrayList<String>();
        for (final File fileEntry : folder.listFiles()) {
            if (fileEntry.isDirectory()) {
                listFilesForFolder(fileEntry);
            } else {
                if (isJar(fileEntry.getName())) {
                    bundles.add(fileEntry.getAbsolutePath().replace(
                            File.separatorChar, '/'));
                }
            }
        }
        return bundles.toArray(new String[0]);
    }

    @Override
    public void start(BundleContext context) throws Exception {
        this.context = context;
        installStart("third-party");
        installStart("shared-components");
        installStart("lumina");
        installStart("webconsole");
        System.out
                .println("-> You can access Felix WebConsole at http://localhost:8080/system/console");
        Thread.sleep(2000);
        installStart("plugins");
    }

    private final void installStart(String path) throws BundleException {
        print("Installing " + path);
        final String[] targetBundles = listFilesForFolder(new File(relativePath
                + path));
        final Bundle[] bundles = new Bundle[targetBundles.length];
        for (int i = 0; i < targetBundles.length; i++) {
            bundles[i] = install(targetBundles[i]);
        }
        print("\tStarting installed bundles...");
        for (Bundle b : bundles)
            b.start();
    }

    @Override
    public void stop(BundleContext arg0) throws Exception {
    }

}

And this is how I organized my bundles in felix's bundle/ folder.

C:\felix\BUNDLE
│   .gitignore
│   lumina.launcher-1.0.0-SNAPSHOT.jar
│
├───lumina
│       .gitignore
│       lumina.api-0.0.4-SNAPSHOT.jar
│
├───plugins
│       .gitignore
│       lumina.assembler-0.0.1-SNAPSHOT.jar
│       lumina.extensions.drivers.ip-0.0.1-SNAPSHOT.jar
│       lumina.rest-0.0.4-SNAPSHOT.jar
│       shared.extensions.base.logger-1.0.2-SNAPSHOT.jar
│       smartcampuskndriver.gateway-0.0.1-SNAPSHOT.jar
│       smartcampusmetersip.gateway-0.0.1-SNAPSHOT.jar
│
├───shared-components
│       codebase-2.0.0.jar
│       shared.osgi.services-1.3.0-SNAPSHOT.jar
│       shared.osgi.services.logger-1.0.0-SNAPSHOT.jar
│       shared.properties.api-5.2.1-SNAPSHOT.jar
│
├───third-party
│       com.googlecode.json-simple_1.1.0.jar
│       org.apache.felix.bundlerepository-2.0.2.jar
│       org.apache.servicemix.bundles.joda-time-2.3_1.jar
│       org.apache.servicemix.bundles.junit-4.11_1.jar
│       org.osgi.compendium-1.4.0.jar
│       org.osgi.core-1.4.0.jar
│       org.restlet.ext.json_2.1.0.M1.jar
│       org.restlet.jse.org.restlet.lib.org.json_2.0.0.jar
│       org.restlet_2.1.0.M1.jar
│       OSGiJMX.jar
│
├───unused
│       org.apache.felix.gogo.command-0.14.0.jar
│       org.apache.felix.gogo.runtime-0.12.1.jar
│       org.apache.felix.gogo.shell-0.10.0.jar
│
└───webconsole
        org.apache.felix.http.api-2.3.2.jar
        org.apache.felix.http.jetty-2.3.2.jar
        org.apache.felix.http.servlet-api-1.0.1.jar
        org.apache.felix.webconsole-4.2.4-all.jar

Note that lumina.launcher-1.0.0-SNAPSHOT.jar is where my Activator is and is the only bundle auto-started by felix.

This works fine by the way, dunno if there is a smarter way to do this. So the idea of the above code is to start all bundles from each directory by the following order: third-party, shared-components, lumina, webconsole and plugins.

On the other hand, when I hit ^C in the terminal while the OSGi container is running, it begins stopping all bundles one by one. This is ok, but the log service is one of the first bundles to stop, and I want it to be one of the last bundles. Is there a way to set the order by which bundles are stopped when the OSGi container is closing?

Thanks!

Answer 1

I needed this because the framework would start some bundles before their dependencies have finished starting.

One of the rules of OSGi is that all bundles should be implemented in the way that starting order does not matter.

In case you really need starting order, you should set start levels for your bundles. See chapter 10.5 of OSGi core specification to get more information about start levels.