## org.apache.log4j
Class PropertyConfigurator

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

All Implemented Interfaces:
  Configurator

    public class PropertyConfigurator

extends java.lang.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 for `Filters`, 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 java.lang.String` `LOGGER_FACTORY_KEY` Key for specifying the `LoggerFactory`.
`protected LoggerFactory` `loggerFactory`
`protected java.util.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(java.util.Properties properties)` Read configuration options from `properties`.
`static void` `configure(java.lang.String configFilename)`
`static void` `configure(java.net.URL configURL)` Read configuration options from url `configURL`.
`static void` `configureAndWatch(java.lang.String configFilename)` Like `configureAndWatch(String, long)` except that the default delay as defined by `FileWatchdog.DEFAULT_DELAY` is used.
`static void` `configureAndWatch(java.lang.String configFilename, long delay)` Read the configuration file `configFilename` if it exists.
`protected void` `configureLoggerFactory(java.util.Properties props)` Check the provided `Properties` object for a `LoggerFactory` entry specified by `LOGGER_FACTORY_KEY`.
`void` `doConfigure(java.util.Properties properties, LoggerRepository hierarchy)` Read configuration options from `properties`.
`void` `doConfigure(java.lang.String configFileName, LoggerRepository hierarchy)` Read configuration from a file.
`void` `doConfigure(java.net.URL configURL, LoggerRepository hierarchy)` Read configuration options from url `configURL`.
`protected void` `parseCatsAndRenderers(java.util.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 java.util.Hashtable registry

  Used internally to keep track of configured appenders.

### loggerFactory

    protected LoggerFactory loggerFactory

### LOGGER_FACTORY_KEY

    public static final java.lang.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(java.lang.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

  ### 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

  ### 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(java.lang.String configFilename)

### configure

    public static void configure(java.net.URL configURL)

  Read configuration options from url `configURL`.

  Since:
    0.8.2

### configure

    public static void configure(java.util.Properties properties)

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

### configureAndWatch

    public static void configureAndWatch(java.lang.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(java.lang.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(java.util.Properties properties,
                            LoggerRepository hierarchy)

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

### doConfigure

    public void doConfigure(java.net.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(java.util.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(java.util.Properties props,
                                         LoggerRepository hierarchy)

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

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