001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.apache.logging.log4j.core.osgi;
019
020import java.util.concurrent.atomic.AtomicReference;
021
022import org.apache.logging.log4j.Logger;
023import org.apache.logging.log4j.core.config.plugins.util.PluginRegistry;
024import org.apache.logging.log4j.core.util.Constants;
025import org.apache.logging.log4j.status.StatusLogger;
026import org.apache.logging.log4j.util.PropertiesUtil;
027import org.osgi.framework.Bundle;
028import org.osgi.framework.BundleActivator;
029import org.osgi.framework.BundleContext;
030import org.osgi.framework.BundleEvent;
031import org.osgi.framework.SynchronousBundleListener;
032import org.osgi.framework.wiring.BundleWiring;
033
034/**
035 * OSGi BundleActivator.
036 */
037public final class Activator implements BundleActivator, SynchronousBundleListener {
038
039    private static final Logger LOGGER = StatusLogger.getLogger();
040
041    private final AtomicReference<BundleContext> context = new AtomicReference<BundleContext>();
042
043    @Override
044    public void start(final BundleContext context) throws Exception {
045        // allow the user to override the default ContextSelector (e.g., by using BasicContextSelector for a global cfg)
046        if (PropertiesUtil.getProperties().getStringProperty(Constants.LOG4J_CONTEXT_SELECTOR) == null) {
047            System.setProperty(Constants.LOG4J_CONTEXT_SELECTOR, BundleContextSelector.class.getName());
048        }
049        if (this.context.compareAndSet(null, context)) {
050            context.addBundleListener(this);
051            // done after the BundleListener as to not miss any new bundle installs in the interim
052            scanInstalledBundlesForPlugins(context);
053        }
054    }
055
056    private static void scanInstalledBundlesForPlugins(final BundleContext context) {
057        final Bundle[] bundles = context.getBundles();
058        for (final Bundle bundle : bundles) {
059            if (bundle.getState() == Bundle.ACTIVE) {
060                // TODO: bundle state can change during this
061                scanBundleForPlugins(bundle);
062            }
063        }
064    }
065
066    private static void scanBundleForPlugins(final Bundle bundle) {
067        LOGGER.trace("Scanning bundle [{}] for plugins.", bundle.getSymbolicName());
068        PluginRegistry.getInstance().loadFromBundle(bundle.getBundleId(),
069            bundle.adapt(BundleWiring.class).getClassLoader());
070    }
071
072    private static void stopBundlePlugins(final Bundle bundle) {
073        LOGGER.trace("Stopping bundle [{}] plugins.", bundle.getSymbolicName());
074        // TODO: plugin lifecycle code
075        PluginRegistry.getInstance().clearBundlePlugins(bundle.getBundleId());
076    }
077
078    @Override
079    public void stop(final BundleContext context) throws Exception {
080        // not much can be done that isn't already automated by the framework
081        this.context.compareAndSet(context, null);
082        // TODO: shut down log4j
083    }
084
085    @Override
086    public void bundleChanged(final BundleEvent event) {
087        switch (event.getType()) {
088            // FIXME: STARTING instead of STARTED?
089            case BundleEvent.STARTED:
090                scanBundleForPlugins(event.getBundle());
091                break;
092
093            case BundleEvent.STOPPING:
094                stopBundlePlugins(event.getBundle());
095                break;
096
097            default:
098                break;
099        }
100    }
101}