LogManager class to retreive {@link Logger}
* instances or to operate on the current {@link
* LoggerRepository}. When the LogManager class is loaded
* into memory the default initalzation procedure is inititated. The
* default intialization procedure is described in the short log4j manual.
*
* @author Ceki Gülcü */
public class LogManager {
/**
* @deprecated This variable is for internal use only. It will
* become package protected in future versions.
* */
static public final String DEFAULT_CONFIGURATION_FILE = "log4j.properties";
static final String DEFAULT_XML_CONFIGURATION_FILE = "log4j.xml";
/**
* @deprecated This variable is for internal use only. It will
* become private in future versions.
* */
static final public String DEFAULT_CONFIGURATION_KEY="log4j.configuration";
/**
* @deprecated This variable is for internal use only. It will
* become private in future versions.
* */
static final public String CONFIGURATOR_CLASS_KEY="log4j.configuratorClass";
/**
* @deprecated This variable is for internal use only. It will
* become private in future versions.
*/
public static final String DEFAULT_INIT_OVERRIDE_KEY =
"log4j.defaultInitOverride";
static private Object guard = null;
static private RepositorySelector repositorySelector;
static {
// By default we use a DefaultRepositorySelector which always returns 'h'.
Hierarchy h = new Hierarchy(new RootLogger((Level) Level.DEBUG));
repositorySelector = new DefaultRepositorySelector(h);
/** Search for the properties file log4j.properties in the CLASSPATH. */
String override =OptionConverter.getSystemProperty(DEFAULT_INIT_OVERRIDE_KEY,
null);
// if there is no default init override, then get the resource
// specified by the user or the default config file.
if(override == null || "false".equalsIgnoreCase(override)) {
String configurationOptionStr = OptionConverter.getSystemProperty(
DEFAULT_CONFIGURATION_KEY,
null);
String configuratorClassName = OptionConverter.getSystemProperty(
CONFIGURATOR_CLASS_KEY,
null);
URL url = null;
// if the user has not specified the log4j.configuration
// property, we search first for the file "log4j.xml" and then
// "log4j.properties"
if(configurationOptionStr == null) {
url = Loader.getResource(DEFAULT_XML_CONFIGURATION_FILE);
if(url == null) {
url = Loader.getResource(DEFAULT_CONFIGURATION_FILE);
}
} else {
try {
url = new URL(configurationOptionStr);
} catch (MalformedURLException ex) {
// so, resource is not a URL:
// attempt to get the resource from the class path
url = Loader.getResource(configurationOptionStr);
}
}
// If we have a non-null url, then delegate the rest of the
// configuration to the OptionConverter.selectAndConfigure
// method.
if(url != null) {
LogLog.debug("Using URL ["+url+"] for automatic log4j configuration.");
try {
OptionConverter.selectAndConfigure(url, configuratorClassName,
LogManager.getLoggerRepository());
} catch (NoClassDefFoundError e) {
LogLog.warn("Error during default initialization", e);
}
} else {
LogLog.debug("Could not find resource: ["+configurationOptionStr+"].");
}
}
}
/**
Sets LoggerFactory but only if the correct
guard is passed as parameter.
Initally the guard is null. If the guard is
null, then invoking this method sets the logger
factory and the guard. Following invocations will throw a {@link
IllegalArgumentException}, unless the previously set
guard is passed as the second parameter.
This allows a high-level component to set the {@link
RepositorySelector} used by the LogManager.
For example, when tomcat starts it will be able to install its own repository selector. However, if and when Tomcat is embedded within JBoss, then JBoss will install its own repository selector and Tomcat will use the repository selector set by its container, JBoss. */ static public void setRepositorySelector(RepositorySelector selector, Object guard) throws IllegalArgumentException { if((LogManager.guard != null) && (LogManager.guard != guard)) { throw new IllegalArgumentException( "Attempted to reset the LoggerFactory without possessing the guard."); } if(selector == null) { throw new IllegalArgumentException("RepositorySelector must be non-null."); } LogManager.guard = guard; LogManager.repositorySelector = selector; } static public LoggerRepository getLoggerRepository() { if (repositorySelector == null) { repositorySelector = new DefaultRepositorySelector(new NOPLoggerRepository()); guard = null; LogLog.error("LogMananger.repositorySelector was null likely due to error in class reloading, using NOPLoggerRepository."); } return repositorySelector.getLoggerRepository(); } /** Retrieve the appropriate root logger. */ public static Logger getRootLogger() { // Delegate the actual manufacturing of the logger to the logger repository. return getLoggerRepository().getRootLogger(); } /** Retrieve the appropriate {@link Logger} instance. */ public static Logger getLogger(final String name) { // Delegate the actual manufacturing of the logger to the logger repository. return getLoggerRepository().getLogger(name); } /** Retrieve the appropriate {@link Logger} instance. */ public static Logger getLogger(final Class clazz) { // Delegate the actual manufacturing of the logger to the logger repository. return getLoggerRepository().getLogger(clazz.getName()); } /** Retrieve the appropriate {@link Logger} instance. */ public static Logger getLogger(final String name, final LoggerFactory factory) { // Delegate the actual manufacturing of the logger to the logger repository. return getLoggerRepository().getLogger(name, factory); } public static Logger exists(final String name) { return getLoggerRepository().exists(name); } public static Enumeration getCurrentLoggers() { return getLoggerRepository().getCurrentLoggers(); } public static void shutdown() { getLoggerRepository().shutdown(); } public static void resetConfiguration() { getLoggerRepository().resetConfiguration(); } }