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What this is

This file is included in the "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

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The source code

 * Copyright (C) The Apache Software Foundation. All rights reserved.
 * This software is published under the terms of the Apache Software
 * License version 1.1, a copy of which has been included with this
 * distribution in the LICENSE.txt file.  */

// Contibutors: "Luke Blanshard" 
//              "Mark DONSZELMANN" 
//               Anders Kristensen 

package org.apache.log4j;

import org.apache.log4j.DefaultCategoryFactory;
import org.apache.log4j.config.PropertySetter;
//import org.apache.log4j.config.PropertySetterException;
import org.apache.log4j.spi.OptionHandler;
import org.apache.log4j.spi.Configurator;
import org.apache.log4j.spi.LoggerFactory;
import org.apache.log4j.spi.LoggerRepository;
import org.apache.log4j.spi.RendererSupport;
import org.apache.log4j.or.RendererMap;
import org.apache.log4j.helpers.LogLog;
import org.apache.log4j.helpers.OptionConverter;
import org.apache.log4j.helpers.FileWatchdog;

import java.util.Enumeration;
import java.util.Properties;
import java.util.StringTokenizer;
import java.util.Hashtable;

   Allows the configuration of log4j from an external file.  See
   {@link #doConfigure(String, LoggerRepository)} for the
   expected format.


It is sometimes useful to see how log4j is reading configuration files. You can enable log4j internal logging by defining the log4j.debug variable.

As of log4j version 0.8.5, at class initialization time class, the file will be searched from the search path used to load classes. If the file can be found, then it will be fed to the {@link PropertyConfigurator#configure(} method.

The PropertyConfigurator does not handle the advanced configuration features supported by the {@link org.apache.log4j.xml.DOMConfigurator DOMConfigurator} such as support for {@link org.apache.log4j.spi.Filter Filters}, custom {@link org.apache.log4j.spi.ErrorHandler ErrorHandlers}, nested appenders such as the {@link org.apache.log4j.AsyncAppender AsyncAppender}, etc.

All option values admit variable substitution. The syntax of variable substitution is similar to that of Unix shells. The string between an opening "${" and closing "}" is interpreted as a key. The value of the substituted variable can be defined as a system property or in the configuration file itself. The value of the key is first searched in the system properties, and if not found there, it is then searched in the configuration file being parsed. The corresponding value replaces the ${variableName} sequence. For example, if java.home system property is set to /home/xyz, then every occurrence of the sequence ${java.home} will be interpreted as /home/xyz. @author Ceki Gülcü @author Anders Kristensen @since 0.8.1 */ public class PropertyConfigurator implements Configurator { /** Used internally to keep track of configured appenders. */ protected Hashtable registry = new Hashtable(11); protected LoggerFactory loggerFactory = new DefaultCategoryFactory(); static final String CATEGORY_PREFIX = "log4j.category."; static final String LOGGER_PREFIX = "log4j.logger."; static final String FACTORY_PREFIX = "log4j.factory"; static final String ADDITIVITY_PREFIX = "log4j.additivity."; static final String ROOT_CATEGORY_PREFIX = "log4j.rootCategory"; static final String ROOT_LOGGER_PREFIX = "log4j.rootLogger"; static final String APPENDER_PREFIX = "log4j.appender."; static final String RENDERER_PREFIX = "log4j.renderer."; static final String THRESHOLD_PREFIX = "log4j.threshold"; /** Key for specifying the {@link org.apache.log4j.spi.LoggerFactory LoggerFactory}. Currently set to "log4j.loggerFactory". */ public static final String LOGGER_FACTORY_KEY = "log4j.loggerFactory"; static final private String INTERNAL_ROOT_NAME = "root"; /** Read configuration from a file. The existing configuration is not cleared nor reset. If you require a different behavior, then call {@link LogManager#resetConfiguration resetConfiguration} method before calling doConfigure.

The configuration file consists of statements in the format key=value. The syntax of different configuration elements are discussed below.

Repository-wide threshold

The repository-wide threshold filters logging requests by level regardless of logger. The syntax is:


The level value can consist of the string values OFF, FATAL, ERROR, WARN, INFO, DEBUG, ALL or a custom level value. A custom level value can be specified in the form level#classname. By default the repository-wide threshold is set to the lowest possible value, namely the level ALL.

Appender configuration

Appender configuration syntax is:

    # For appender named appenderName, set its class.
    # Note: The appender name can contain dots.

    # Set appender specific options.
For each named appender you can configure its {@link Layout}. The syntax for configuring an appender's layout is:

Configuring loggers

The syntax for configuring the root logger is:

      log4j.rootLogger=[level], appenderName, appenderName, ...

This syntax means that an optional level can be supplied followed by appender names separated by commas.

The level value can consist of the string values OFF, FATAL, ERROR, WARN, INFO, DEBUG, ALL or a custom level value. A custom level value can be specified in the form level#classname.

If a level value is specified, then the root level is set to the corresponding level. If no level value is specified, then the root level remains untouched.

The root logger can be assigned multiple appenders.

Each appenderName (separated by commas) will be added to the root logger. The named appender is defined using the appender syntax defined above.

For non-root categories the syntax is almost the same:

    log4j.logger.logger_name=[level|INHERITED|NULL], appenderName, appenderName, ...

The meaning of the optional level value is discussed above in relation to the root logger. In addition however, the value INHERITED can be specified meaning that the named logger should inherit its level from the logger hierarchy.

If no level value is supplied, then the level of the named logger remains untouched.

By default categories inherit their level from the hierarchy. However, if you set the level of a logger and later decide that that logger should inherit its level, then you should specify INHERITED as the value for the level value. NULL is a synonym for INHERITED.

Similar to the root logger syntax, each appenderName (separated by commas) will be attached to the named logger.

See the appender additivity rule in the user manual for the meaning of the additivity flag.


You can customize the way message objects of a given type are converted to String before being logged. This is done by specifying an {@link org.apache.log4j.or.ObjectRenderer ObjectRenderer} for the object type would like to customize.

The syntax is:
As in,

Logger Factories

The usage of custom logger factories is discouraged and no longer documented.


An example configuration is given below. Other configuration file examples are given in the examples folder.

    # Set options for appender named "A1".
    # Appender "A1" will be a SyslogAppender

    # The syslog daemon resides on

    # A1's layout is a PatternLayout, using the conversion pattern
    # %r %-5p %c{2} %M.%L %x - %m\n. Thus, the log output will
    # include # the relative time since the start of the application in
    # milliseconds, followed by the level of the log request,
    # followed by the two rightmost components of the logger name,
    # followed by the callers method name, followed by the line number,
    # the nested disgnostic context and finally the message itself.
    # Refer to the documentation of {@link PatternLayout} for further information
    # on the syntax of the ConversionPattern key.
    log4j.appender.A1.layout.ConversionPattern=%-4r %-5p %c{2} %M.%L %x - %m\n

    # Set options for appender named "A2"
    # A2 should be a RollingFileAppender, with maximum file size of 10 MB
    # using at most one backup file. A2's layout is TTCC, using the
    # ISO8061 date format with context printing enabled.

    # Root logger set to DEBUG using the A2 appender defined above.
    log4j.rootLogger=DEBUG, A2

    # Logger definitions:
    # The SECURITY logger inherits is level from root. However, it's output
    # will go to A1 appender defined above. It's additivity is non-cumulative.
    log4j.logger.SECURITY=INHERIT, A1

    # Only warnings or above will be logged for the logger "SECURITY.access".
    # Output will go to A1.

    # The logger "" inherits its level from the
    # logger hierarchy.  Output will go to the appender's of the root
    # logger, A2 in this case.

Refer to the setOption method in each Appender and Layout for class specific options.

Use the # or ! characters at the beginning of a line for comments.

@param configFileName The name of the configuration file where the configuration information is stored. */ public void doConfigure(String configFileName, LoggerRepository hierarchy) { Properties props = new Properties(); try { FileInputStream istream = new FileInputStream(configFileName); props.load(istream); istream.close(); } catch (IOException e) { LogLog.error("Could not read configuration file ["+configFileName+"].", e); LogLog.error("Ignoring configuration file [" + configFileName+"]."); return; } // If we reach here, then the config file is alright. doConfigure(props, hierarchy); } /** */ static public void configure(String configFilename) { new PropertyConfigurator().doConfigure(configFilename, LogManager.getLoggerRepository()); } /** Read configuration options from url configURL. @since 0.8.2 */ public static void configure( configURL) { new PropertyConfigurator().doConfigure(configURL, LogManager.getLoggerRepository()); } /** Read configuration options from properties. See {@link #doConfigure(String, LoggerRepository)} for the expected format. */ static public void configure(Properties properties) { new PropertyConfigurator().doConfigure(properties, LogManager.getLoggerRepository()); } /** Like {@link #configureAndWatch(String, long)} except that the default delay as defined by {@link FileWatchdog#DEFAULT_DELAY} is used. @param configFilename A file in key=value format. */ static public void configureAndWatch(String configFilename) { configureAndWatch(configFilename, FileWatchdog.DEFAULT_DELAY); } /** Read the configuration file configFilename if it exists. Moreover, a thread will be created that will periodically check if configFilename has been created or modified. The period is determined by the delay argument. If a change or file creation is detected, then configFilename is read to configure log4j. @param configFilename A file in key=value format. @param delay The delay in milliseconds to wait between each check. */ static public void configureAndWatch(String configFilename, long delay) { PropertyWatchdog pdog = new PropertyWatchdog(configFilename); pdog.setDelay(delay); pdog.start(); } /** Read configuration options from properties. See {@link #doConfigure(String, LoggerRepository)} for the expected format. */ public void doConfigure(Properties properties, LoggerRepository hierarchy) { String value = properties.getProperty(LogLog.DEBUG_KEY); if(value == null) { value = properties.getProperty(LogLog.CONFIG_DEBUG_KEY); if(value != null) LogLog.warn("[log4j.configDebug] is deprecated. Use [log4j.debug] instead."); } if(value != null) { LogLog.setInternalDebugging(OptionConverter.toBoolean(value, true)); } String thresholdStr = OptionConverter.findAndSubst(THRESHOLD_PREFIX, properties); if(thresholdStr != null) { hierarchy.setThreshold(OptionConverter.toLevel(thresholdStr, (Level) Level.ALL)); LogLog.debug("Hierarchy threshold set to ["+hierarchy.getThreshold()+"]."); } configureRootCategory(properties, hierarchy); configureLoggerFactory(properties); parseCatsAndRenderers(properties, hierarchy); LogLog.debug("Finished configuring."); // We don't want to hold references to appenders preventing their // garbage collection. registry.clear(); } /** Read configuration options from url configURL. */ public void doConfigure( configURL, LoggerRepository hierarchy) { Properties props = new Properties(); LogLog.debug("Reading configuration from URL " + configURL); try { props.load(configURL.openStream()); } catch ( e) { LogLog.error("Could not read configuration file from URL [" + configURL + "].", e); LogLog.error("Ignoring configuration file [" + configURL +"]."); return; } doConfigure(props, hierarchy); } // -------------------------------------------------------------------------- // Internal stuff // -------------------------------------------------------------------------- /** Check the provided Properties object for a {@link org.apache.log4j.spi.LoggerFactory LoggerFactory} entry specified by {@link #LOGGER_FACTORY_KEY}. If such an entry exists, an attempt is made to create an instance using the default constructor. This instance is used for subsequent Category creations within this configurator. @see #parseCatsAndRenderers */ protected void configureLoggerFactory(Properties props) { String factoryClassName = OptionConverter.findAndSubst(LOGGER_FACTORY_KEY, props); if(factoryClassName != null) { LogLog.debug("Setting category factory to ["+factoryClassName+"]."); loggerFactory = (LoggerFactory) OptionConverter.instantiateByClassName(factoryClassName, LoggerFactory.class, loggerFactory); PropertySetter.setProperties(loggerFactory, props, FACTORY_PREFIX + "."); } } /* void configureOptionHandler(OptionHandler oh, String prefix, Properties props) { String[] options = oh.getOptionStrings(); if(options == null) return; String value; for(int i = 0; i < options.length; i++) { value = OptionConverter.findAndSubst(prefix + options[i], props); LogLog.debug( "Option " + options[i] + "=[" + (value == null? "N/A" : value)+"]."); // Some option handlers assume that null value are not passed to them. // So don't remove this check if(value != null) { oh.setOption(options[i], value); } } oh.activateOptions(); } */ void configureRootCategory(Properties props, LoggerRepository hierarchy) { String effectiveFrefix = ROOT_LOGGER_PREFIX; String value = OptionConverter.findAndSubst(ROOT_LOGGER_PREFIX, props); if(value == null) { value = OptionConverter.findAndSubst(ROOT_CATEGORY_PREFIX, props); effectiveFrefix = ROOT_CATEGORY_PREFIX; } if(value == null) LogLog.debug("Could not find root logger information. Is this OK?"); else { Logger root = hierarchy.getRootLogger(); synchronized(root) { parseCategory(props, root, effectiveFrefix, INTERNAL_ROOT_NAME, value); } } } /** Parse non-root elements, such non-root categories and renderers. */ protected void parseCatsAndRenderers(Properties props, LoggerRepository hierarchy) { Enumeration enum = props.propertyNames(); while(enum.hasMoreElements()) { String key = (String) enum.nextElement(); if(key.startsWith(CATEGORY_PREFIX) || key.startsWith(LOGGER_PREFIX)) { String loggerName = null; if(key.startsWith(CATEGORY_PREFIX)) { loggerName = key.substring(CATEGORY_PREFIX.length()); } else if(key.startsWith(LOGGER_PREFIX)) { loggerName = key.substring(LOGGER_PREFIX.length()); } String value = OptionConverter.findAndSubst(key, props); Logger logger = hierarchy.getLogger(loggerName, loggerFactory); synchronized(logger) { parseCategory(props, logger, key, loggerName, value); parseAdditivityForLogger(props, logger, loggerName); } } else if(key.startsWith(RENDERER_PREFIX)) { String renderedClass = key.substring(RENDERER_PREFIX.length()); String renderingClass = OptionConverter.findAndSubst(key, props); if(hierarchy instanceof RendererSupport) { RendererMap.addRenderer((RendererSupport) hierarchy, renderedClass, renderingClass); } } } } /** Parse the additivity option for a non-root category. */ void parseAdditivityForLogger(Properties props, Logger cat, String loggerName) { String value = OptionConverter.findAndSubst(ADDITIVITY_PREFIX + loggerName, props); LogLog.debug("Handling "+ADDITIVITY_PREFIX + loggerName+"=["+value+"]"); // touch additivity only if necessary if((value != null) && (!value.equals(""))) { boolean additivity = OptionConverter.toBoolean(value, true); LogLog.debug("Setting additivity for \""+loggerName+"\" to "+ additivity); cat.setAdditivity(additivity); } } /** This method must work for the root category as well. */ void parseCategory(Properties props, Logger logger, String optionKey, String loggerName, String value) { LogLog.debug("Parsing for [" +loggerName +"] with value=[" + value+"]."); // We must skip over ',' but not white space StringTokenizer st = new StringTokenizer(value, ","); // If value is not in the form ", appender.." or "", then we should set // the level of the loggeregory. if(!(value.startsWith(",") || value.equals(""))) { // just to be on the safe side... if(!st.hasMoreTokens()) return; String levelStr = st.nextToken(); LogLog.debug("Level token is [" + levelStr + "]."); // If the level value is inherited, set category level value to // null. We also check that the user has not specified inherited for the // root category. if(INHERITED.equalsIgnoreCase(levelStr) || NULL.equalsIgnoreCase(levelStr)) { if(loggerName.equals(INTERNAL_ROOT_NAME)) { LogLog.warn("The root logger cannot be set to null."); } else { logger.setLevel(null); } } else { logger.setLevel(OptionConverter.toLevel(levelStr, (Level) Level.DEBUG)); } LogLog.debug("Category " + loggerName + " set to " + logger.getLevel()); } // Begin by removing all existing appenders. logger.removeAllAppenders(); Appender appender; String appenderName; while(st.hasMoreTokens()) { appenderName = st.nextToken().trim(); if(appenderName == null || appenderName.equals(",")) continue; LogLog.debug("Parsing appender named \"" + appenderName +"\"."); appender = parseAppender(props, appenderName); if(appender != null) { logger.addAppender(appender); } } } Appender parseAppender(Properties props, String appenderName) { Appender appender = registryGet(appenderName); if((appender != null)) { LogLog.debug("Appender \"" + appenderName + "\" was already parsed."); return appender; } // Appender was not previously initialized. String prefix = APPENDER_PREFIX + appenderName; String layoutPrefix = prefix + ".layout"; appender = (Appender) OptionConverter.instantiateByKey(props, prefix, org.apache.log4j.Appender.class, null); if(appender == null) { LogLog.error( "Could not instantiate appender named \"" + appenderName+"\"."); return null; } appender.setName(appenderName); if(appender instanceof OptionHandler) { if(appender.requiresLayout()) { Layout layout = (Layout) OptionConverter.instantiateByKey(props, layoutPrefix, Layout.class, null); if(layout != null) { appender.setLayout(layout); LogLog.debug("Parsing layout options for \"" + appenderName +"\"."); //configureOptionHandler(layout, layoutPrefix + ".", props); PropertySetter.setProperties(layout, props, layoutPrefix + "."); LogLog.debug("End of parsing for \"" + appenderName +"\"."); } } //configureOptionHandler((OptionHandler) appender, prefix + ".", props); PropertySetter.setProperties(appender, props, prefix + "."); LogLog.debug("Parsed \"" + appenderName +"\" options."); } registryPut(appender); return appender; } void registryPut(Appender appender) { registry.put(appender.getName(), appender); } Appender registryGet(String name) { return (Appender) registry.get(name); } } class PropertyWatchdog extends FileWatchdog { PropertyWatchdog(String filename) { super(filename); } /** Call {@link PropertyConfigurator#configure(String)} with the filename to reconfigure log4j. */ public void doOnChange() { new PropertyConfigurator().doConfigure(filename, LogManager.getLoggerRepository()); } }

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