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    package org.apache.logging.log4j.core.osgi;
018    
019    import java.lang.ref.WeakReference;
020    import java.net.URI;
021    import java.util.concurrent.atomic.AtomicReference;
022    
023    import org.apache.logging.log4j.core.LoggerContext;
024    import org.apache.logging.log4j.core.impl.ContextAnchor;
025    import org.apache.logging.log4j.core.selector.ClassLoaderContextSelector;
026    import org.apache.logging.log4j.core.selector.ContextSelector;
027    import org.apache.logging.log4j.core.util.Assert;
028    import org.apache.logging.log4j.util.ReflectionUtil;
029    import org.osgi.framework.Bundle;
030    import org.osgi.framework.BundleReference;
031    import org.osgi.framework.FrameworkUtil;
032    
033    /**
034     * ContextSelector for OSGi bundles. This ContextSelector works rather similarly to the
035     * {@link ClassLoaderContextSelector}, but instead of each ClassLoader having its own LoggerContext (like in a
036     * servlet container), each OSGi bundle has its own LoggerContext.
037     *
038     * @since 2.1
039     */
040    public class BundleContextSelector extends ClassLoaderContextSelector implements ContextSelector {
041    
042        @Override
043        public LoggerContext getContext(final String fqcn, final ClassLoader loader, final boolean currentContext,
044                                        final URI configLocation) {
045            if (currentContext) {
046                final LoggerContext ctx = ContextAnchor.THREAD_CONTEXT.get();
047                if (ctx != null) {
048                    return ctx;
049                }
050                return getDefault();
051            }
052            // it's quite possible that the provided ClassLoader may implement BundleReference which gives us a nice shortcut
053            if (loader instanceof BundleReference) {
054                return locateContext(((BundleReference) loader).getBundle(), configLocation);
055            }
056            final Class<?> callerClass = ReflectionUtil.getCallerClass(fqcn);
057            if (callerClass != null) {
058                return locateContext(FrameworkUtil.getBundle(callerClass), configLocation);
059            }
060            final LoggerContext lc = ContextAnchor.THREAD_CONTEXT.get();
061            return lc == null ? getDefault() : lc;
062        }
063    
064        private static LoggerContext locateContext(final Bundle bundle, final URI configLocation) {
065            final String name = Assert.requireNonNull(bundle, "No Bundle provided").getSymbolicName();
066            final AtomicReference<WeakReference<LoggerContext>> ref = CONTEXT_MAP.get(name);
067            if (ref == null) {
068                final LoggerContext context = new LoggerContext(name, bundle, configLocation);
069                CONTEXT_MAP.putIfAbsent(name,
070                    new AtomicReference<WeakReference<LoggerContext>>(new WeakReference<LoggerContext>(context)));
071                return CONTEXT_MAP.get(name).get().get();
072            }
073            final WeakReference<LoggerContext> r = ref.get();
074            final LoggerContext ctx = r.get();
075            if (ctx == null) {
076                final LoggerContext context = new LoggerContext(name, bundle, configLocation);
077                ref.compareAndSet(r, new WeakReference<LoggerContext>(context));
078                return ref.get().get();
079            }
080            final URI oldConfigLocation = ctx.getConfigLocation();
081            if (oldConfigLocation == null && configLocation != null) {
082                LOGGER.debug("Setting bundle ({}) configuration to {}", name, configLocation);
083                ctx.setConfigLocation(configLocation);
084            } else if (oldConfigLocation != null && configLocation != null && !configLocation.equals(oldConfigLocation)) {
085                LOGGER.warn("locateContext called with URI [{}], but existing LoggerContext has URI [{}]",
086                    configLocation, oldConfigLocation);
087            }
088            return ctx;
089        }
090    }