org.apache.logging.log4j.util.Constants Maven / Gradle / Ivy
/*
* 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.util;
/**
* Log4j API Constants.
*
* @since 2.6.2
*/
public final class Constants {
/**
* {@code true} if we think we are running in a web container, based on the boolean value of system property
* "log4j2.is.webapp", or (if this system property is not set) whether the {@code javax.servlet.Servlet} class
* is present in the classpath.
*/
public static final boolean IS_WEB_APP = PropertiesUtil.getProperties().getBooleanProperty(
"log4j2.is.webapp", isClassAvailable("javax.servlet.Servlet")
|| isClassAvailable("jakarta.servlet.Servlet"));
/**
* Kill switch for object pooling in ThreadLocals that enables much of the LOG4J2-1270 no-GC behaviour.
*
* {@code True} for non-{@link #IS_WEB_APP web apps}, disable by setting system property
* "log4j2.enable.threadlocals" to "false".
*
*/
public static final boolean ENABLE_THREADLOCALS = !IS_WEB_APP && PropertiesUtil.getProperties().getBooleanProperty(
"log4j2.enable.threadlocals", true);
/**
* Java major version.
*/
public static final int JAVA_MAJOR_VERSION = getMajorVersion();
/**
* Maximum size of the StringBuilders used in RingBuffer LogEvents to store the contents of reusable Messages.
* After a large message has been delivered to the appenders, the StringBuilder is trimmed to this size.
*
* The default value is {@value}, which allows the StringBuilder to resize three times from its initial size.
* Users can override with system property "log4j.maxReusableMsgSize".
*
* @since 2.9
*/
public static final int MAX_REUSABLE_MESSAGE_SIZE = size("log4j.maxReusableMsgSize", (128 * 2 + 2) * 2 + 2);
/**
* Name of the system property that will turn on TRACE level internal log4j2 status logging.
*
* If system property {@value} is either defined empty or its value equals to {@code true} (ignoring case), all internal log4j2 logging will be
* printed to the console. The presence of this system property overrides any value set in the configuration's
* {@code } status attribute, as well as any value set for
* system property {@code org.apache.logging.log4j.simplelog.StatusLogger.level}.
*
*/
public static final String LOG4J2_DEBUG = "log4j2.debug";
private static int size(final String property, final int defaultValue) {
return PropertiesUtil.getProperties().getIntegerProperty(property, defaultValue);
}
/**
* Determines if a named Class can be loaded or not.
*
* @param className The class name.
* @return {@code true} if the class could be found or {@code false} otherwise.
*/
private static boolean isClassAvailable(final String className) {
try {
return LoaderUtil.loadClass(className) != null;
} catch (final Throwable e) {
return false;
}
}
/**
* The empty array.
*/
public static final Object[] EMPTY_OBJECT_ARRAY = {};
/**
* The empty array.
*/
public static final byte[] EMPTY_BYTE_ARRAY = {};
/**
* Prevent class instantiation.
*/
private Constants() {
}
private static int getMajorVersion() {
return getMajorVersion(System.getProperty("java.version"));
}
static int getMajorVersion(final String version) {
final String[] parts = version.split("-|\\.");
boolean isJEP223;
try {
final int token = Integer.parseInt(parts[0]);
isJEP223 = token != 1;
if (isJEP223) {
return token;
}
return Integer.parseInt(parts[1]);
} catch (final Exception ex) {
return 0;
}
}
}