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/appender/db/jdbc/DataSourceConnectionSource.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.appender.db.jdbc;

import java.sql.Connection;
import java.sql.SQLException;

import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.sql.DataSource;

import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.core.Core;
import org.apache.logging.log4j.core.config.plugins.Plugin;
import org.apache.logging.log4j.core.config.plugins.PluginAttribute;
import org.apache.logging.log4j.core.config.plugins.PluginFactory;
import org.apache.logging.log4j.status.StatusLogger;
import org.apache.logging.log4j.util.Strings;

/**
 * A {@link JdbcAppender} connection source that uses a {@link DataSource} to connect to the database.
 */
@Plugin(name = "DataSource", category = Core.CATEGORY_NAME, elementType = "connectionSource", printObject = true)
public final class DataSourceConnectionSource extends AbstractConnectionSource {
    private static final Logger LOGGER = StatusLogger.getLogger();

    private final DataSource dataSource;
    private final String description;

    private DataSourceConnectionSource(final String dataSourceName, final DataSource dataSource) {
        this.dataSource = dataSource;
        this.description = "dataSource{ name=" + dataSourceName + ", value=" + dataSource + " }";
    }

    @Override
    public Connection getConnection() throws SQLException {
        return this.dataSource.getConnection();
    }

    @Override
    public String toString() {
        return this.description;
    }

    /**
     * Factory method for creating a connection source within the plugin manager.
     *
     * @param jndiName The full JNDI path where the data source is bound. Should start with java:/comp/env or
     *                 environment-equivalent.
     * @return the created connection source.
     */
    @PluginFactory
    public static DataSourceConnectionSource createConnectionSource(@PluginAttribute("jndiName") final String jndiName) {
        if (Strings.isEmpty(jndiName)) {
            LOGGER.error("No JNDI name provided.");
            return null;
        }

        try {
            final InitialContext context = new InitialContext();
            final DataSource dataSource = (DataSource) context.lookup(jndiName);
            if (dataSource == null) {
                LOGGER.error("No data source found with JNDI name [" + jndiName + "].");
                return null;
            }

            return new DataSourceConnectionSource(jndiName, dataSource);
        } catch (final NamingException e) {
            LOGGER.error(e.getMessage(), e);
            return null;
        }
    }
}

⏎ org/apache/logging/log4j/core/appender/db/jdbc/DataSourceConnectionSource.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
Download 

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