org.apache.commons.logging

Class LogFactory

java.lang.Object

org.apache.commons.logging.LogFactory

public class LogFactory
extends Object

This is an adaptation of the Jakarta Commons Logging API that returns a logger that does nothing.

Author:

Alin Dreghiciu, Craig R. McClanahan, Costin Manolache, Richard A. Sitze

Method Summary

Methods

Modifier and Type	Method and Description
Object	getAttribute(String name) Return the configuration attribute with the specified name (if any), or null if there is no such attribute.
String[]	getAttributeNames() Return an array containing the names of all currently defined configuration attributes.
static LogFactory	getFactory()
Log	getInstance(Class clazz) Convenience method to derive a name from the specified class and call getInstance(String) with it.
Log	getInstance(String name) Construct (if necessary) and return a Log instance, using the factory's current set of configuration attributes.
static Log	getLog(Class clazz) Convenience method to return a named logger, without the application having to care about factories.
static Log	getLog(String name) Convenience method to return a named logger, without the application having to care about factories.
static void	release() Release any internal references to previously created Log instances returned by this factory.
static void	release(ClassLoader classLoader) Release any internal references to previously created LogFactory instances that have been associated with the specified class loader (if any), after calling the instance method release() on each of them.
static void	releaseAll() Release any internal references to previously created LogFactory instances, after calling the instance method release() on each of them.
void	removeAttribute(String name) Remove any configuration attribute associated with the specified name.
void	setAttribute(String name, Object value) Set the configuration attribute with the specified name.

Methods inherited from class java.lang.Object

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

Method Detail

getFactory

public static LogFactory getFactory()
                             throws LogConfigurationException

Returns:

the LogFactory instance to use.

Throws:

LogConfigurationException - if the implementation class is not available or cannot be instantiated.

getLog

public static Log getLog(Class clazz)
                  throws LogConfigurationException

Convenience method to return a named logger, without the application having to care about factories.

Parameters:

clazz - Class from which a log name will be derived

Returns:

the Log instance to use for the class

Throws:

LogConfigurationException - if a suitable Log instance cannot be returned

getLog

public static Log getLog(String name)
                  throws LogConfigurationException

Convenience method to return a named logger, without the application having to care about factories.

Parameters:

name - Logical name of the Log instance to be returned (the meaning of this name is only known to the underlying logging implementation that is being wrapped)

Returns:

the Log instance to use for the class of the given name

Throws:

LogConfigurationException - if a suitable Log instance cannot be returned

release

public static void release(ClassLoader classLoader)

Release any internal references to previously created LogFactory instances that have been associated with the specified class loader (if any), after calling the instance method release() on each of them.

Parameters:

classLoader - ClassLoader for which to release the LogFactory

releaseAll

public static void releaseAll()

Release any internal references to previously created LogFactory instances, after calling the instance method release() on each of them. This is useful in environments like servlet containers, which implement application reloading by throwing away a ClassLoader. Dangling references to objects in that class loader would prevent garbage collection.

getAttribute

public Object getAttribute(String name)

Return the configuration attribute with the specified name (if any), or null if there is no such attribute.

Parameters:

name - Name of the attribute to return

Returns:

always return null. This method is not supported in Pax Logging.

getAttributeNames

public String[] getAttributeNames()

Return an array containing the names of all currently defined configuration attributes. If there are no such attributes, a zero length array is returned.

Returns:

always returns an emtpy String array. This method is not supported in Pax Logging.

getInstance

public Log getInstance(Class clazz)
                throws LogConfigurationException

Convenience method to derive a name from the specified class and call getInstance(String) with it.

Parameters:

clazz - Class for which a suitable Log name will be derived

Returns:

the Log instance to use for the given class.

Throws:

LogConfigurationException - if a suitable Log instance cannot be returned

getInstance

public Log getInstance(String name)
                throws LogConfigurationException

Construct (if necessary) and return a Log instance, using the factory's current set of configuration attributes.

NOTE - Depending upon the implementation of the LogFactory you are using, the Log instance you are returned may or may not be local to the current application, and may or may not be returned again on a subsequent call with the same name argument.

Parameters:

name - Logical name of the Log instance to be returned (the meaning of this name is only known to the underlying logging implementation that is being wrapped)

Returns:

the Log instance of the class with the given name.

Throws:

LogConfigurationException - if a suitable Log instance cannot be returned

release

public static void release()

Release any internal references to previously created Log instances returned by this factory. This is useful in environments like servlet containers, which implement application reloading by throwing away a ClassLoader. Dangling references to objects in that class loader would prevent garbage collection.

removeAttribute

public void removeAttribute(String name)

Remove any configuration attribute associated with the specified name. If there is no such attribute, no action is taken.

Parameters:

name - Name of the attribute to remove

setAttribute

public void setAttribute(String name,
                Object value)

Set the configuration attribute with the specified name. Calling this with a null value is equivalent to calling removeAttribute(name).

Parameters:

name - Name of the attribute to set

value - Value of the attribute to set, or null to remove any setting for this attribute