/*
* Copyright 2002-2008 the original author or authors.
*
* Licensed 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.springframework.util;
import java.io.File;
import java.io.FileNotFoundException;
import java.net.URL;
import org.apache.log4j.LogManager;
import org.apache.log4j.PropertyConfigurator;
import org.apache.log4j.xml.DOMConfigurator;
/**
* Convenience class that features simple methods for custom log4j configuration.
*
* <p>Only needed for non-default log4j initialization, for example with a custom
* config location or a refresh interval. By default, log4j will simply read its
* configuration from a "log4j.properties" or "log4j.xml" file in the root of
* the classpath.
*
* <p>For web environments, the analogous Log4jWebConfigurer class can be found
* in the web package, reading in its configuration from context-params in
* <code>web.xml</code>. In a J2EE web application, log4j is usually set up
* via Log4jConfigListener or Log4jConfigServlet, delegating to
* Log4jWebConfigurer underneath.
*
* @author Juergen Hoeller
* @since 13.03.2003
* @see org.springframework.web.util.Log4jWebConfigurer
* @see org.springframework.web.util.Log4jConfigListener
* @see org.springframework.web.util.Log4jConfigServlet
*/
public abstract class Log4jConfigurer {
/** Pseudo URL prefix for loading from the class path: "classpath:" */
public static final String CLASSPATH_URL_PREFIX = "classpath:";
/** Extension that indicates a log4j XML config file: ".xml" */
public static final String XML_FILE_EXTENSION = ".xml";
/**
* Initialize log4j from the given file location, with no config file refreshing.
* Assumes an XML file in case of a ".xml" file extension, and a properties file
* otherwise.
* @param location the location of the config file: either a "classpath:" location
* (e.g. "classpath:myLog4j.properties"), an absolute file URL
* (e.g. "file:C:/log4j.properties), or a plain absolute path in the file system
* (e.g. "C:/log4j.properties")
* @throws FileNotFoundException if the location specifies an invalid file path
*/
public static void initLogging(String location) throws FileNotFoundException {
String resolvedLocation = SystemPropertyUtils.resolvePlaceholders(location);
URL url = ResourceUtils.getURL(resolvedLocation);
if (resolvedLocation.toLowerCase().endsWith(XML_FILE_EXTENSION)) {
DOMConfigurator.configure(url);
}
else {
PropertyConfigurator.configure(url);
}
}
/**
* Initialize log4j from the given location, with the given refresh interval
* for the config file. Assumes an XML file in case of a ".xml" file extension,
* and a properties file otherwise.
* <p>Log4j's watchdog thread will asynchronously check whether the timestamp
* of the config file has changed, using the given interval between checks.
* A refresh interval of 1000 milliseconds (one second), which allows to
* do on-demand log level changes with immediate effect, is not unfeasible.
* <p><b>WARNING:</b> Log4j's watchdog thread does not terminate until VM shutdown;
* in particular, it does not terminate on LogManager shutdown. Therefore, it is
* recommended to <i>not</i> use config file refreshing in a production J2EE
* environment; the watchdog thread would not stop on application shutdown there.
* @param location the location of the config file: either a "classpath:" location
* (e.g. "classpath:myLog4j.properties"), an absolute file URL
* (e.g. "file:C:/log4j.properties), or a plain absolute path in the file system
* (e.g. "C:/log4j.properties")
* @param refreshInterval interval between config file refresh checks, in milliseconds
* @throws FileNotFoundException if the location specifies an invalid file path
*/
public static void initLogging(String location, long refreshInterval) throws FileNotFoundException {
String resolvedLocation = SystemPropertyUtils.resolvePlaceholders(location);
File file = ResourceUtils.getFile(resolvedLocation);
if (!file.exists()) {
throw new FileNotFoundException("Log4j config file [" + resolvedLocation + "] not found");
}
if (resolvedLocation.toLowerCase().endsWith(XML_FILE_EXTENSION)) {
DOMConfigurator.configureAndWatch(file.getAbsolutePath(), refreshInterval);
}
else {
PropertyConfigurator.configureAndWatch(file.getAbsolutePath(), refreshInterval);
}
}
/**
* Shut down log4j, properly releasing all file locks.
* <p>This isn't strictly necessary, but recommended for shutting down
* log4j in a scenario where the host VM stays alive (for example, when
* shutting down an application in a J2EE environment).
*/
public static void shutdownLogging() {
LogManager.shutdown();
}
/**
* Set the specified system property to the current working directory.
* <p>This can be used e.g. for test environments, for applications that leverage
* Log4jWebConfigurer's "webAppRootKey" support in a web environment.
* @param key system property key to use, as expected in Log4j configuration
* (for example: "demo.root", used as "${demo.root}/WEB-INF/demo.log")
* @see org.springframework.web.util.Log4jWebConfigurer
*/
public static void setWorkingDirSystemProperty(String key) {
System.setProperty(key, new File("").getAbsolutePath());
}
}