Source Code for Apache Log4j Core Implementation

Apache Log4j Core Implementation provides the functional components of the logging system. Users are free to create their own plugins and include them in the logging configuration. Apache Log4j Core is a required module to use Apache Log4j.

Bytecode (Java 8) for Apache Log4j Core Implementation is provided in a separate JAR file like log4j-core-2.14.1.jar.

Source Code files for Apache Log4j API are provided in both binary packge like apache-log4j-2.14.1-bin.zip and source package like apache-log4j-2.14.1-src.zip. You can download them at Apache Log4j Website.

You can also browse Source Code files for Apache Log4j Core Implementation 2.14.1 below.

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org/apache/logging/log4j/core/osgi/BundleContextSelector.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.logging.log4j.core.osgi;

import java.lang.ref.WeakReference;
import java.net.URI;
import java.util.Objects;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicReference;

import org.apache.logging.log4j.core.LoggerContext;
import org.apache.logging.log4j.core.impl.ContextAnchor;
import org.apache.logging.log4j.core.selector.ClassLoaderContextSelector;
import org.apache.logging.log4j.util.StackLocatorUtil;
import org.osgi.framework.Bundle;
import org.osgi.framework.BundleReference;
import org.osgi.framework.FrameworkUtil;

/**
 * ContextSelector for OSGi bundles. This ContextSelector works rather similarly to the
 * {@link ClassLoaderContextSelector}, but instead of each ClassLoader having its own LoggerContext (like in a
 * servlet container), each OSGi bundle has its own LoggerContext.
 *
 * @since 2.1
 */
public class BundleContextSelector extends ClassLoaderContextSelector {

    @Override
    public void shutdown(final String fqcn, final ClassLoader loader, final boolean currentContext,
                         final boolean allContexts) {
        LoggerContext ctx = null;
        Bundle bundle = null;
        if (currentContext) {
            ctx = ContextAnchor.THREAD_CONTEXT.get();
            ContextAnchor.THREAD_CONTEXT.remove();
        }
        if (ctx == null && loader instanceof BundleReference) {
            bundle = ((BundleReference) loader).getBundle();
            ctx = getLoggerContext(bundle);
            removeLoggerContext(ctx);
        }
        if (ctx == null) {
            final Class<?> callerClass = StackLocatorUtil.getCallerClass(fqcn);
            if (callerClass != null) {
                bundle = FrameworkUtil.getBundle(callerClass);
                ctx = getLoggerContext(FrameworkUtil.getBundle(callerClass));
                removeLoggerContext(ctx);
            }
        }
        if (ctx == null) {
            ctx = ContextAnchor.THREAD_CONTEXT.get();
            ContextAnchor.THREAD_CONTEXT.remove();
        }
        if (ctx != null) {
            ctx.stop(DEFAULT_STOP_TIMEOUT, TimeUnit.MILLISECONDS);
        }
        if (bundle != null && allContexts) {
            final Bundle[] bundles = bundle.getBundleContext().getBundles();
            for (final Bundle bdl : bundles) {
                ctx = getLoggerContext(bdl);
                if (ctx != null) {
                    ctx.stop(DEFAULT_STOP_TIMEOUT, TimeUnit.MILLISECONDS);
                }
            }
        }
    }
    private LoggerContext getLoggerContext(final Bundle bundle) {
        final String name = Objects.requireNonNull(bundle, "No Bundle provided").getSymbolicName();
        final AtomicReference<WeakReference<LoggerContext>> ref = CONTEXT_MAP.get(name);
        if (ref != null && ref.get() != null) {
            return ref.get().get();
        }
        return null;
    }

    private void removeLoggerContext(LoggerContext context) {
        CONTEXT_MAP.remove(context.getName());
    }

    @Override
    public boolean hasContext(final String fqcn, final ClassLoader loader, final boolean currentContext) {
        if (currentContext && ContextAnchor.THREAD_CONTEXT.get() != null) {
            return ContextAnchor.THREAD_CONTEXT.get().isStarted();
        }
        if (loader instanceof BundleReference) {
            return hasContext(((BundleReference) loader).getBundle());
        }
        final Class<?> callerClass = StackLocatorUtil.getCallerClass(fqcn);
        if (callerClass != null) {
            return hasContext(FrameworkUtil.getBundle(callerClass));
        }
        return ContextAnchor.THREAD_CONTEXT.get() != null && ContextAnchor.THREAD_CONTEXT.get().isStarted();
    }
    @Override
    public LoggerContext getContext(final String fqcn, final ClassLoader loader, final boolean currentContext,
                                    final URI configLocation) {
        if (currentContext) {
            final LoggerContext ctx = ContextAnchor.THREAD_CONTEXT.get();
            if (ctx != null) {
                return ctx;
            }
            return getDefault();
        }
        // it's quite possible that the provided ClassLoader may implement BundleReference which gives us a nice shortcut
        if (loader instanceof BundleReference) {
            return locateContext(((BundleReference) loader).getBundle(), configLocation);
        }
        final Class<?> callerClass = StackLocatorUtil.getCallerClass(fqcn);
        if (callerClass != null) {
            return locateContext(FrameworkUtil.getBundle(callerClass), configLocation);
        }
        final LoggerContext lc = ContextAnchor.THREAD_CONTEXT.get();
        return lc == null ? getDefault() : lc;
    }

    private static boolean hasContext(final Bundle bundle) {
        final String name = Objects.requireNonNull(bundle, "No Bundle provided").getSymbolicName();
        final AtomicReference<WeakReference<LoggerContext>> ref = CONTEXT_MAP.get(name);
        return ref != null && ref.get() != null && ref.get().get() != null && ref.get().get().isStarted();
    }

    private static LoggerContext locateContext(final Bundle bundle, final URI configLocation) {
        final String name = Objects.requireNonNull(bundle, "No Bundle provided").getSymbolicName();
        final AtomicReference<WeakReference<LoggerContext>> ref = CONTEXT_MAP.get(name);
        if (ref == null) {
            final LoggerContext context = new LoggerContext(name, bundle, configLocation);
            CONTEXT_MAP.putIfAbsent(name,
                new AtomicReference<>(new WeakReference<>(context)));
            return CONTEXT_MAP.get(name).get().get();
        }
        final WeakReference<LoggerContext> r = ref.get();
        final LoggerContext ctx = r.get();
        if (ctx == null) {
            final LoggerContext context = new LoggerContext(name, bundle, configLocation);
            ref.compareAndSet(r, new WeakReference<>(context));
            return ref.get().get();
        }
        final URI oldConfigLocation = ctx.getConfigLocation();
        if (oldConfigLocation == null && configLocation != null) {
            LOGGER.debug("Setting bundle ({}) configuration to {}", name, configLocation);
            ctx.setConfigLocation(configLocation);
        } else if (oldConfigLocation != null && configLocation != null && !configLocation.equals(oldConfigLocation)) {
            LOGGER.warn("locateContext called with URI [{}], but existing LoggerContext has URI [{}]",
                configLocation, oldConfigLocation);
        }
        return ctx;
    }
}

org/apache/logging/log4j/core/osgi/BundleContextSelector.java

 

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File name: log4j-core-2.14.1-sources.jar
File size: 1281358 bytes
Release date: 2021-03-06
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