org.apache.log4j
Class PropertyConfigurator

java.lang.Object
  org.apache.log4j.PropertyConfigurator

All Implemented Interfaces:

Configurator

public class PropertyConfigurator
extends Object
implements Configurator

Allows the configuration of log4j from an external file. See 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 log4j.properties will be searched from the search path used to load classes. If the file can be found, then it will be fed to the configure(java.net.URL) method.

The PropertyConfigurator does not handle the advanced configuration features supported by the DOMConfigurator such as support custom ErrorHandlers, nested appenders such as the 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.

Since:

0.8.1

Author:

Ceki Gülcü, Anders Kristensen

Field Summary

static String	LOGGER_FACTORY_KEY Key for specifying the LoggerFactory.
protected LoggerFactory	loggerFactory
protected Hashtable	registry Used internally to keep track of configured appenders.

Fields inherited from interface org.apache.log4j.spi.Configurator

INHERITED, NULL

Constructor Summary

PropertyConfigurator()

Method Summary

static void	configure(Properties properties) Read configuration options from properties.
static void	configure(String configFilename)
static void	configure(URL configURL) Read configuration options from url configURL.
static void	configureAndWatch(String configFilename) Like configureAndWatch(String, long) except that the default delay as defined by FileWatchdog.DEFAULT_DELAY is used.
static void	configureAndWatch(String configFilename, long delay) Read the configuration file configFilename if it exists.
protected void	configureLoggerFactory(Properties props) Check the provided Properties object for a LoggerFactory entry specified by LOGGER_FACTORY_KEY.
void	doConfigure(Properties properties, LoggerRepository hierarchy) Read configuration options from properties.
void	doConfigure(String configFileName, LoggerRepository hierarchy) Read configuration from a file.
void	doConfigure(URL configURL, LoggerRepository hierarchy) Read configuration options from url configURL.
protected void	parseCatsAndRenderers(Properties props, LoggerRepository hierarchy) Parse non-root elements, such non-root categories and renderers.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

registry

protected Hashtable registry

Used internally to keep track of configured appenders.

loggerFactory

protected LoggerFactory loggerFactory

LOGGER_FACTORY_KEY

public static final String LOGGER_FACTORY_KEY

Key for specifying the LoggerFactory. Currently set to "log4j.loggerFactory".

See Also:

Constant Field Values

Constructor Detail

PropertyConfigurator

public PropertyConfigurator()

Method Detail

doConfigure

public void doConfigure(String configFileName,
                        LoggerRepository hierarchy)

Read configuration from a file. The existing configuration is not cleared nor reset. If you require a different behavior, then call 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:

    log4j.threshold=[level]
    

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.
    log4j.appender.appenderName=fully.qualified.name.of.appender.class

    # Set appender specific options.
    log4j.appender.appenderName.option1=value1
    ...
    log4j.appender.appenderName.optionN=valueN
    

For each named appender you can configure its Layout. The syntax for configuring an appender's layout is:

    log4j.appender.appenderName.layout=fully.qualified.name.of.layout.class
    log4j.appender.appenderName.layout.option1=value1
    ....
    log4j.appender.appenderName.layout.optionN=valueN
    

The syntax for adding Filters to an appender is:

    log4j.appender.appenderName.filter.ID=fully.qualified.name.of.filter.class
    log4j.appender.appenderName.filter.ID.option1=value1
    ...
    log4j.appender.appenderName.filter.ID.optionN=valueN
    

The first line defines the class name of the filter identified by ID; subsequent lines with the same ID specify filter option - value paris. Multiple filters are added to the appender in the lexicographic order of IDs. The syntax for adding an ErrorHandler to an appender is:

    log4j.appender.appenderName.errorhandler=fully.qualified.name.of.filter.class
    log4j.appender.appenderName.errorhandler.root-ref={true|false}
    log4j.appender.appenderName.errorhandler.logger-ref=loggerName
    log4j.appender.appenderName.errorhandler.appender-ref=appenderName
    log4j.appender.appenderName.errorhandler.option1=value1
    ...
    log4j.appender.appenderName.errorhandler.optionN=valueN
    

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.

ObjectRenderers

You can customize the way message objects of a given type are converted to String before being logged. This is done by specifying an ObjectRenderer for the object type would like to customize.

The syntax is:

    log4j.renderer.fully.qualified.name.of.rendered.class=fully.qualified.name.of.rendering.class
    

As in,

    log4j.renderer.my.Fruit=my.FruitRenderer
    

ThrowableRenderer

You can customize the way an instance of Throwable is converted to String before being logged. This is done by specifying an ThrowableRenderer.

The syntax is:

   log4j.throwableRenderer=fully.qualified.name.of.rendering.class
   log4j.throwableRenderer.paramName=paramValue
   

As in,

   log4j.throwableRenderer=org.apache.log4j.EnhancedThrowableRenderer
   

Logger Factories

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

Resetting Hierarchy

The hierarchy will be reset before configuration when log4j.reset=true is present in the properties file.

Example

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
    log4j.appender.A1=org.apache.log4j.net.SyslogAppender

    # The syslog daemon resides on www.abc.net
    log4j.appender.A1.SyslogHost=www.abc.net

    # 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 PatternLayout for further information
    # on the syntax of the ConversionPattern key.
    log4j.appender.A1.layout=org.apache.log4j.PatternLayout
    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.
    log4j.appender.A2=org.apache.log4j.RollingFileAppender
    log4j.appender.A2.MaxFileSize=10MB
    log4j.appender.A2.MaxBackupIndex=1
    log4j.appender.A2.layout=org.apache.log4j.TTCCLayout
    log4j.appender.A2.layout.ContextPrinting=enabled
    log4j.appender.A2.layout.DateFormat=ISO8601

    # 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
    log4j.additivity.SECURITY=false

    # Only warnings or above will be logged for the logger "SECURITY.access".
    # Output will go to A1.
    log4j.logger.SECURITY.access=WARN


    # The logger "class.of.the.day" inherits its level from the
    # logger hierarchy.  Output will go to the appender's of the root
    # logger, A2 in this case.
    log4j.logger.class.of.the.day=INHERIT
    

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.

Parameters:

configFileName - The name of the configuration file where the configuration information is stored.

configure

public static void configure(String configFilename)

configure

public static void configure(URL configURL)

Read configuration options from url configURL.

Since:

0.8.2

configure

public static void configure(Properties properties)

Read configuration options from properties. See doConfigure(String, LoggerRepository) for the expected format.

configureAndWatch

public static void configureAndWatch(String configFilename)

Like configureAndWatch(String, long) except that the default delay as defined by FileWatchdog.DEFAULT_DELAY is used.

Parameters:

configFilename - A file in key=value format.

configureAndWatch

public static void configureAndWatch(String configFilename,
                                     long 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.

Parameters:

configFilename - A file in key=value format.

delay - The delay in milliseconds to wait between each check.

doConfigure

public void doConfigure(Properties properties,
                        LoggerRepository hierarchy)

Read configuration options from properties. See doConfigure(String, LoggerRepository) for the expected format.

doConfigure

public void doConfigure(URL configURL,
                        LoggerRepository hierarchy)

Read configuration options from url configURL.

Specified by:

doConfigure in interface Configurator

Parameters:

configURL - The URL to parse

hierarchy - The hierarchy to operation upon.

configureLoggerFactory

protected void configureLoggerFactory(Properties props)

Check the provided Properties object for a LoggerFactory entry specified by 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 Also:

parseCatsAndRenderers(java.util.Properties, org.apache.log4j.spi.LoggerRepository)

parseCatsAndRenderers

protected void parseCatsAndRenderers(Properties props,
                                     LoggerRepository hierarchy)

Parse non-root elements, such non-root categories and renderers.