dependencymanager/runtime/src/main/java/org/apache/felix/dm/runtime/DependencyManagerRuntime.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.felix.dm.runtime;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ConcurrentHashMap;

import org.apache.felix.dm.DependencyManager;
import org.apache.felix.dm.Component;
import org.osgi.framework.Bundle;
import org.osgi.framework.BundleContext;
import org.osgi.framework.BundleEvent;
import org.osgi.framework.SynchronousBundleListener;
import org.osgi.service.log.LogService;

/**
 * This class parses service descriptors generated by the annotation bnd processor.
 * The descriptors are located under OSGI-INF/dependencymanager directory. Such files are actually 
 * referenced by a specific "DependendencyManager-Component" manifest header.
 */
public class DependencyManagerRuntime implements SynchronousBundleListener
{
    private ConcurrentHashMap<Bundle, DependencyManager> m_managers = new ConcurrentHashMap<Bundle, DependencyManager>();
    private static LogService m_log; // Injected
    private BundleContext m_bctx; // Injected
    private DescriptorParser m_parser;

    /**
     * Starts our Service (at this point, we have been injected with our bundle context, as well
     * as with our log service. We'll listen to bundle start/stop events (we implement the 
     * SynchronousBundleListener interface).
     */
    protected void start()
    {
        // Register our log service.
        Log.instance().setLogService(m_log);
        
        // Instantiates our descriptor parser, and register our service builders into it.
        m_parser = new DescriptorParser();
        m_parser.addBuilder(new ComponentBuilder());
        m_parser.addBuilder(new AspectServiceBuilder());
        m_parser.addBuilder(new AdapterServiceBuilder());
        m_parser.addBuilder(new BundleAdapterServiceBuilder());
        m_parser.addBuilder(new FactoryConfigurationAdapterServiceBuilder());
        m_parser.addBuilder(new ResourceAdapterServiceBuilder());

        // Load already started bundles
        for (Bundle b: m_bctx.getBundles())
        {
            if (b.getState() == Bundle.ACTIVE)
            {
                bundleChanged(new BundleEvent(Bundle.ACTIVE, b));
            }
        }

        // Track bundles
        m_bctx.addBundleListener(this);
    }

    /**
     * Stops our service. We'll stop all activated DependencyManager services.
     */
    @SuppressWarnings("unchecked")
    protected void stop()
    {
        m_log.log(LogService.LOG_INFO, "Runtime: stopping services");

        for (DependencyManager dm: m_managers.values())
        {
            List<Component> services = new ArrayList<Component>(dm.getServices());
            for (Component service: services)
            {
                dm.remove(service);
            }
        }

        m_managers.clear();
    }

    /**
     * Register a LogService, so other components may use it
     */
    protected void bind(LogService logService) {
        m_log = logService;
        Log.instance().setLogService(logService);
    }
    
    /**
     * Handle a bundle event, and eventually parse started bundles.
     */
    public void bundleChanged(BundleEvent event)
    {
        Bundle b = event.getBundle();
        if (b.getState() == Bundle.ACTIVE)
        {
            bundleStarted(b);
        }
        else if (b.getState() == Bundle.STOPPING)
        {
            bundleStopping(b);
        }
    }

    /**
     * Checks if a started bundle have some DependencyManager descriptors 
     * referenced in the "DependencyManager-Component" OSGi header.
     * @param b the started bundle.
     */
    void bundleStarted(Bundle b)
    {
        String descriptorPaths = (String) b.getHeaders().get("DependencyManager-Component");
        if (descriptorPaths == null)
        {
            return;
        }

        for (String descriptorPath: descriptorPaths.split(","))
        {
            URL descriptorURL = b.getEntry(descriptorPath);
            if (descriptorURL == null)
            {
                m_log.log(LogService.LOG_ERROR, "Runtime: " +
                          "DependencyManager component descriptor not found: " + descriptorPath);
                continue;
            }
            loadDescriptor(b, descriptorURL);
        }
    }

    /**
     * Unregisters all services for a stopping bundle.
     * @param b
     */
    @SuppressWarnings("unchecked")
    private void bundleStopping(Bundle b)
    {
        m_log.log(LogService.LOG_INFO, "Runtime: Removing services from stopping bundle: " + b.getSymbolicName());
        DependencyManager dm = m_managers.remove(b);
        if (dm != null)
        {
            List<Component> services = new ArrayList(dm.getServices());
            for (Component service : services)
            {
                m_log.log(LogService.LOG_INFO, "Runtime: Removing service: " + service);
                dm.remove(service);
            }            
        }
    }

    /**
     * Load a DependencyManager component descriptor from a given bundle.
     * @param b
     * @param descriptorURL
     */
    private void loadDescriptor(Bundle b, URL descriptorURL)
    {
        m_log.log(LogService.LOG_DEBUG, "Runtime: ++++ Parsing descriptor " + descriptorURL
            + " from bundle " + b.getSymbolicName());

        BufferedReader in = null;
        try
        {
            in = new BufferedReader(new InputStreamReader(descriptorURL.openStream()));
            DependencyManager dm = m_managers.get(b);
            if (dm == null)
            {
                dm = new DependencyManager(b.getBundleContext());
                m_managers.put(b, dm);
            }

            m_parser.parse(in, b, dm);
            m_managers.put(b, dm);
        }

        catch (Throwable t)
        {
            m_log.log(LogService.LOG_ERROR, "Runtime: Error while parsing descriptor "
                + descriptorURL + " from bundle " + b.getSymbolicName(), t);
        }

        finally
        {
            if (in != null)
            {
                try
                {
                    in.close();
                }
                catch (IOException ignored)
                {
                }
            }
        }
    }
}