org.apache.log4j
Class Hierarchy

java.lang.Object
  org.apache.log4j.Hierarchy

All Implemented Interfaces:

LoggerRepository, RendererSupport, ThrowableRendererSupport

public class Hierarchy
extends Object
implements LoggerRepository, RendererSupport, ThrowableRendererSupport

This class is specialized in retrieving loggers by name and also maintaining the logger hierarchy.

The casual user does not have to deal with this class directly.

The structure of the logger hierarchy is maintained by the getLogger(java.lang.String) method. The hierarchy is such that children link to their parent but parents do not have any pointers to their children. Moreover, loggers can be instantiated in any order, in particular descendant before ancestor.

In case a descendant is created before a particular ancestor, then it creates a provision node for the ancestor and adds itself to the provision node. Other descendants of the same ancestor add themselves to the previously created provision node.

Author:

Ceki Gülcü

Constructor Summary

Hierarchy(Logger root)
Create a new logger hierarchy.

Method Summary

void	addHierarchyEventListener(HierarchyEventListener listener) Add a HierarchyEventListener event to the repository.
void	addRenderer(Class classToRender, ObjectRenderer or) Add an object renderer for a specific class.
void	clear() This call will clear all logger definitions from the internal hashtable.
void	emitNoAppenderWarning(Category cat)
Logger	exists(String name) Check if the named logger exists in the hierarchy.
void	fireAddAppenderEvent(Category logger, Appender appender)
Enumeration	getCurrentCategories() Deprecated. Please use getCurrentLoggers() instead.
Enumeration	getCurrentLoggers() Returns all the currently defined categories in this hierarchy as an Enumeration.
Logger	getLogger(String name) Return a new logger instance named as the first parameter using the default factory.
Logger	getLogger(String name, LoggerFactory factory) Return a new logger instance named as the first parameter using factory.
RendererMap	getRendererMap() Get the renderer map for this hierarchy.
Logger	getRootLogger() Get the root of this hierarchy.
Level	getThreshold() Returns a Level representation of the enable state.
ThrowableRenderer	getThrowableRenderer() Get throwable renderer.
boolean	isDisabled(int level) This method will return true if this repository is disabled for level object passed as parameter and false otherwise.
void	overrideAsNeeded(String override) Deprecated. Deprecated with no replacement.
void	resetConfiguration() Reset all values contained in this hierarchy instance to their default.
void	setDisableOverride(String override) Deprecated. Deprecated with no replacement.
void	setRenderer(Class renderedClass, ObjectRenderer renderer) Used by subclasses to add a renderer to the hierarchy passed as parameter.
void	setThreshold(Level l) Enable logging for logging requests with level l or higher.
void	setThreshold(String levelStr) The string form of setThreshold(Level).
void	setThrowableRenderer(ThrowableRenderer renderer) Set throwable renderer.
void	shutdown() Shutting down a hierarchy will safely close and remove all appenders in all categories including the root logger.

Methods inherited from class java.lang.Object

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

Constructor Detail

Hierarchy

public Hierarchy(Logger root)

Create a new logger hierarchy.

Parameters:

root - The root of the new hierarchy.

Method Detail

addRenderer

public void addRenderer(Class classToRender,
                        ObjectRenderer or)

Add an object renderer for a specific class.

addHierarchyEventListener

public void addHierarchyEventListener(HierarchyEventListener listener)

Description copied from interface: LoggerRepository

Add a HierarchyEventListener event to the repository.

Specified by:

addHierarchyEventListener in interface LoggerRepository

clear

public void clear()

This call will clear all logger definitions from the internal hashtable. Invoking this method will irrevocably mess up the logger hierarchy.

You should really know what you are doing before invoking this method.

Since:

0.9.0

emitNoAppenderWarning

public void emitNoAppenderWarning(Category cat)

Specified by:

emitNoAppenderWarning in interface LoggerRepository

exists

public Logger exists(String name)

Check if the named logger exists in the hierarchy. If so return its reference, otherwise returns null.

Specified by:

exists in interface LoggerRepository

Parameters:

name - The name of the logger to search for.

setThreshold

public void setThreshold(String levelStr)

The string form of setThreshold(Level).

Specified by:

setThreshold in interface LoggerRepository

setThreshold

public void setThreshold(Level l)

Enable logging for logging requests with level l or higher. By default all levels are enabled.

Specified by:

setThreshold in interface LoggerRepository

Parameters:

l - The minimum level for which logging requests are sent to their appenders.

fireAddAppenderEvent

public void fireAddAppenderEvent(Category logger,
                                 Appender appender)

Specified by:

fireAddAppenderEvent in interface LoggerRepository

getThreshold

public Level getThreshold()

Returns a Level representation of the enable state.

Specified by:

getThreshold in interface LoggerRepository

Since:

1.2

getLogger

public Logger getLogger(String name)

Return a new logger instance named as the first parameter using the default factory.

If a logger of that name already exists, then it will be returned. Otherwise, a new logger will be instantiated and then linked with its existing ancestors as well as children.

Specified by:

getLogger in interface LoggerRepository

Parameters:

name - The name of the logger to retrieve.

getLogger

public Logger getLogger(String name,
                        LoggerFactory factory)

Return a new logger instance named as the first parameter using factory.

If a logger of that name already exists, then it will be returned. Otherwise, a new logger will be instantiated by the factory parameter and linked with its existing ancestors as well as children.

Specified by:

getLogger in interface LoggerRepository

Parameters:

name - The name of the logger to retrieve.

factory - The factory that will make the new logger instance.

getCurrentLoggers

public Enumeration getCurrentLoggers()

Returns all the currently defined categories in this hierarchy as an Enumeration.

The root logger is not included in the returned Enumeration.

Specified by:

getCurrentLoggers in interface LoggerRepository

getCurrentCategories

public Enumeration getCurrentCategories()

Deprecated. Please use getCurrentLoggers() instead.

Description copied from interface: LoggerRepository

Deprecated. Please use LoggerRepository.getCurrentLoggers() instead.

Specified by:

getCurrentCategories in interface LoggerRepository

getRendererMap

public RendererMap getRendererMap()

Get the renderer map for this hierarchy.

Specified by:

getRendererMap in interface RendererSupport

getRootLogger

public Logger getRootLogger()

Get the root of this hierarchy.

Specified by:

getRootLogger in interface LoggerRepository

Since:

0.9.0

isDisabled

public boolean isDisabled(int level)

This method will return true if this repository is disabled for level object passed as parameter and false otherwise. See also the threshold emthod.

Specified by:

isDisabled in interface LoggerRepository

overrideAsNeeded

public void overrideAsNeeded(String override)

Deprecated. Deprecated with no replacement.

resetConfiguration

public void resetConfiguration()

Reset all values contained in this hierarchy instance to their default. This removes all appenders from all categories, sets the level of all non-root categories to null, sets their additivity flag to true and sets the level of the root logger to DEBUG. Moreover, message disabling is set its default "off" value.

Existing categories are not removed. They are just reset.

This method should be used sparingly and with care as it will block all logging until it is completed.

Specified by:

resetConfiguration in interface LoggerRepository

Since:

0.8.5

setDisableOverride

public void setDisableOverride(String override)

Deprecated. Deprecated with no replacement.

Does nothing.

setRenderer

public void setRenderer(Class renderedClass,
                        ObjectRenderer renderer)

Used by subclasses to add a renderer to the hierarchy passed as parameter.

Specified by:

setRenderer in interface RendererSupport

setThrowableRenderer

public void setThrowableRenderer(ThrowableRenderer renderer)

Set throwable renderer.

Specified by:

setThrowableRenderer in interface ThrowableRendererSupport

Parameters:

renderer - renderer, may be null.

getThrowableRenderer

public ThrowableRenderer getThrowableRenderer()

Get throwable renderer.

Specified by:

getThrowableRenderer in interface ThrowableRendererSupport

Returns:

throwable renderer, may be null.

shutdown

public void shutdown()

Shutting down a hierarchy will safely close and remove all appenders in all categories including the root logger.

Some appenders such as SocketAppender and AsyncAppender need to be closed before the application exists. Otherwise, pending logging events might be lost.

The shutdown method is careful to close nested appenders before closing regular appenders. This is allows configurations where a regular appender is attached to a logger and again to a nested appender.

Specified by:

shutdown in interface LoggerRepository

Since:

1.0