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.

⏎ org/apache/logging/log4j/core/util/FileUtils.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.util;

import java.io.File;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.nio.file.FileSystems;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.attribute.GroupPrincipal;
import java.nio.file.attribute.PosixFileAttributeView;
import java.nio.file.attribute.PosixFilePermission;
import java.nio.file.attribute.UserPrincipal;
import java.nio.file.attribute.UserPrincipalLookupService;
import java.util.Objects;
import java.util.Set;

import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.status.StatusLogger;

/**
 * File utilities.
 */
public final class FileUtils {

    /** Constant for the file URL protocol. */
    private static final String PROTOCOL_FILE = "file";

    private static final String JBOSS_FILE = "vfsfile";

    private static final Logger LOGGER = StatusLogger.getLogger();

    private FileUtils() {
    }

    /**
     * Tries to convert the specified URI to a file object. If this fails, <b>null</b> is returned.
     *
     * @param uri the URI
     * @return the resulting file object
     */
    public static File fileFromUri(URI uri) {
        if (uri == null) {
            return null;
        }
        if (uri.isAbsolute()) {
            if (JBOSS_FILE.equals(uri.getScheme())) {
                try {
                    // patch the scheme
                    uri = new URI(PROTOCOL_FILE, uri.getSchemeSpecificPart(), uri.getFragment());
                } catch (URISyntaxException use) {
                    // should not happen, ignore
                }
            }
            try {
                if (PROTOCOL_FILE.equals(uri.getScheme())) {
                    return new File(uri);
                }
            } catch (final Exception ex) {
                LOGGER.warn("Invalid URI {}", uri);
            }
        } else {
            File file = new File(uri.toString());
            try {
                if (file.exists()) {
                    return file;
                }
                final String path = uri.getPath();
                return new File(path);
            } catch (final Exception ex) {
                LOGGER.warn("Invalid URI {}", uri);
            }
        }
        return null;
    }

    public static boolean isFile(final URL url) {
        return url != null && (url.getProtocol().equals(PROTOCOL_FILE) || url.getProtocol().equals(JBOSS_FILE));
    }

    public static String getFileExtension(final File file) {
        final String fileName = file.getName();
        if (fileName.lastIndexOf(".") != -1 && fileName.lastIndexOf(".") != 0) {
            return fileName.substring(fileName.lastIndexOf(".") + 1);
        }
        return null;
    }

    /**
     * Asserts that the given directory exists and creates it if necessary.
     * 
     * @param dir the directory that shall exist
     * @param createDirectoryIfNotExisting specifies if the directory shall be created if it does not exist.
     * @throws java.io.IOException thrown if the directory could not be created.
     */
    public static void mkdir(final File dir, final boolean createDirectoryIfNotExisting) throws IOException {
        // commons io FileUtils.forceMkdir would be useful here, we just want to omit this dependency
        if (!dir.exists()) {
            if (!createDirectoryIfNotExisting) {
                throw new IOException("The directory " + dir.getAbsolutePath() + " does not exist.");
            }
            if (!dir.mkdirs()) {
                throw new IOException("Could not create directory " + dir.getAbsolutePath());
            }
        }
        if (!dir.isDirectory()) {
            throw new IOException("File " + dir + " exists and is not a directory. Unable to create directory.");
        }
    }
    
    /**
     * Creates the parent directories for the given File.
     * 
     * @param file
     * @throws IOException
     */
    public static void makeParentDirs(final File file) throws IOException {
        final File parent = Objects.requireNonNull(file, "file").getCanonicalFile().getParentFile();
        if (parent != null) {
            mkdir(parent, true);
        }
    }

    /**
     * Define file posix attribute view on a path/file.
     *
     * @param path Target path
     * @param filePermissions Permissions to apply
     * @param fileOwner File owner
     * @param fileGroup File group
     * @throws IOException If IO error during definition of file attribute view
     */
    public static void defineFilePosixAttributeView(final Path path,
            final Set<PosixFilePermission> filePermissions,
            final String fileOwner,
            final String fileGroup) throws IOException {
        final PosixFileAttributeView view = Files.getFileAttributeView(path, PosixFileAttributeView.class);
        if (view != null) {
            final UserPrincipalLookupService lookupService = FileSystems.getDefault()
                    .getUserPrincipalLookupService();
            if (fileOwner != null) {
                final UserPrincipal userPrincipal = lookupService.lookupPrincipalByName(fileOwner);
                if (userPrincipal != null) {
                    // If not sudoers member, it will throw Operation not permitted
                    // Only processes with an effective user ID equal to the user ID
                    // of the file or with appropriate privileges may change the ownership of a file.
                    // If _POSIX_CHOWN_RESTRICTED is in effect for path
                    view.setOwner(userPrincipal);
                }
            }
            if (fileGroup != null) {
                final GroupPrincipal groupPrincipal = lookupService.lookupPrincipalByGroupName(fileGroup);
                if (groupPrincipal != null) {
                    // The current user id should be members of this group,
                    // if not will raise Operation not permitted
                    view.setGroup(groupPrincipal);
                }
            }
            if (filePermissions != null) {
                view.setPermissions(filePermissions);
            }
        }
    }

    /**
     * Check if posix file attribute view is supported on the default FileSystem.
     *
     * @return true if posix file attribute view supported, false otherwise
     */
    public static boolean isFilePosixAttributeViewSupported() {
        return FileSystems.getDefault().supportedFileAttributeViews().contains("posix");
    }
}

⏎ org/apache/logging/log4j/core/util/FileUtils.java

Or download all of them as a single archive file:

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