Factory Class — spring-boot Architecture

Source Code

core/spring-boot/src/main/java/org/springframework/boot/logging/log4j2/Log4J2LoggingSystem.java lines 520–540

	@Order(0)
	public static class Factory implements LoggingSystemFactory {

		static final String LOG4J_CORE_CONTEXT_FACTORY = "org.apache.logging.log4j.core.impl.Log4jContextFactory";

		private static final boolean PRESENT = ClassUtils.isPresent(LOG4J_CORE_CONTEXT_FACTORY,
				Factory.class.getClassLoader());

		@Override
		public @Nullable LoggingSystem getLoggingSystem(ClassLoader classLoader) {
			if (PRESENT) {
				org.apache.logging.log4j.spi.LoggerContext spiLoggerContext = LogManager.getContext(classLoader, false);
				Assert.state(spiLoggerContext instanceof LoggerContext, "");
				if (spiLoggerContext instanceof LoggerContext coreLoggerContext) {
					return new Log4J2LoggingSystem(classLoader, coreLoggerContext);
				}
			}
			return null;
		}

	}