Custom Log Factory

CustomLogFactory.java

package my.logger;

import java.text.SimpleDateFormat;
import java.util.Date;

import org.apache.logging.log4j.Level;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.core.Filter.Result;
import org.apache.logging.log4j.core.appender.ConsoleAppender;
import org.apache.logging.log4j.core.config.Configurator;
import org.apache.logging.log4j.core.config.builder.api.AppenderComponentBuilder;
import org.apache.logging.log4j.core.config.builder.api.ConfigurationBuilder;
import org.apache.logging.log4j.core.config.builder.api.ConfigurationBuilderFactory;
import org.apache.logging.log4j.core.config.builder.api.LoggerComponentBuilder;
import org.apache.logging.log4j.core.config.builder.impl.BuiltConfiguration;

public class CustomLogFactory {

	/**
	 * Instantiates a new CustomLogFactory
	 */
	private CustomLogFactory() {
		// No-arg constructor
	}

	/** The Constant LOG_PATTERN. */
	private static final String LOG_PATTERN = "[%d{MM/dd/yyyy HH:mm:ss.SSS zzz}] [%t] [%-5level] %logger{36} Line %L: %M - %msg%n";

	/** The Constant LOG_DIRECTORY. */
	private static final String LOG_DIRECTORY = System.getenv("MY_LOG_DIRECTORY");

	/** The Constant DATE_STAMP. */
	private static final Object DATE_STAMP = (new SimpleDateFormat("yyyyMMdd")).format(new Date());

	/**
	 * Gets the logger.
	 *
	 * @param clazz the class.
	 * @return the logger
	 */
	public static Logger getLogger(Class<?> clazz) {
		configure(clazz);
		
		return LogManager.getLogger(clazz);
	}

	private static void configure(Class<?> clazz) {
		ConfigurationBuilder<BuiltConfiguration> builder = ConfigurationBuilderFactory.newConfigurationBuilder();

		builder.setStatusLevel(Level.INFO);

		/*
		 * Base config
		 */
		// Set configuration name
		String name = getRootPackageName(clazz);
		builder.setConfigurationName(name);

		/*
		 * Appenders
		 */
		configureConsoleAppenders(builder);

		// Add Class Appender
		String regularFileName = clazz.getSimpleName();
		String className = clazz.getCanonicalName();
		String fileName = String.format("%s/%sLog_%s.log", GCLogFactory.LOG_DIRECTORY, regularFileName, GCLogFactory.DATE_STAMP);
		AppenderComponentBuilder fileAppender = builder.newAppender(className, "FILE");
		fileAppender.addAttribute("fileName", fileName);
		fileAppender.add(builder.newFilter("ThresholdFilter", Result.DENY, Result.ACCEPT).addAttribute("level", "ERROR"));
		configurePatternBuilder(builder, fileAppender);
		builder.add(fileAppender);
		
		
		String errorFileName = String.format("%serror", regularFileName);
		String classNameError = String.format("%s_error", className);
		String fileNameError = String.format("%s/%sLogError_%s.log", GCLogFactory.LOG_DIRECTORY, errorFileName, GCLogFactory.DATE_STAMP);
		AppenderComponentBuilder errorFileAppender = builder.newAppender(classNameError, "FILE");
		errorFileAppender.addAttribute("fileName", fileNameError);
		errorFileAppender.add(builder.newFilter("ThresholdFilter", Result.ACCEPT, Result.DENY).addAttribute("level", "ERROR"));
		configurePatternBuilder(builder, errorFileAppender);
		builder.add(errorFileAppender);

		/*
		 * Loggers
		 */
		// Add Logger
		LoggerComponentBuilder logger = builder.newLogger(className, Level.INFO);
		// Add console appender ref
		logger.add(builder.newAppenderRef("Stdout"));

		// Add class appender refs
		logger.add(builder.newAppenderRef(className));
		logger.add(builder.newAppenderRef(classNameError));
		builder.add(logger);

		// Add Root Logger
		builder.add(builder.newRootLogger(Level.ERROR).add(builder.newAppenderRef("Stderr")));

		// Initialize configuration
		Configurator.initialize(builder.build());
	}

	private static void configureConsoleAppenders(ConfigurationBuilder<BuiltConfiguration> builder) {
		// Set Console appender
		AppenderComponentBuilder appenderBuilder = builder.newAppender("Stdout", "CONSOLE");
		appenderBuilder.addAttribute("target", ConsoleAppender.Target.SYSTEM_OUT);
		configurePatternBuilder(builder, appenderBuilder);
		appenderBuilder.add(builder.newFilter("ThresholdFilter", Result.DENY, Result.ACCEPT).addAttribute("level", "ERROR"));
		builder.add(appenderBuilder);

		// Set Console "ERROR" appender
		AppenderComponentBuilder appenderBuilderErr = builder.newAppender("Stderr", "CONSOLE");
		appenderBuilderErr.addAttribute("target", ConsoleAppender.Target.SYSTEM_ERR);
		configurePatternBuilder(builder, appenderBuilderErr);
		appenderBuilderErr.add(builder.newFilter("ThresholdFilter", Result.ACCEPT, Result.DENY).addAttribute("level", "ERROR"));
		builder.add(appenderBuilderErr);
	}

	private static void configurePatternBuilder(ConfigurationBuilder<BuiltConfiguration> builder,
			AppenderComponentBuilder appenderBuilder) {
		appenderBuilder.add(builder.newLayout("PatternLayout").addAttribute("pattern", GCLogFactory.LOG_PATTERN));
	}

	private static String getRootPackageName(Class<?> clazz) {
		clazz.getPackage();
		return Package.getPackages()[0].getName();
	}
}