org.apache.commons.logging
Class LogFactory

java.lang.Object
  extended by org.apache.commons.logging.LogFactory

public class LogFactory
extends java.lang.Object

This is an adaptation of the Jakarta Commons Logging API for OSGi usage.

The client code that wishes to use this adaptation of Jakarta Commons Logging and have the log output to be directed to the Pax Logging Service backend, which is driven by Log4J, it is necessary to;

Typical code looks like this;
 import org.apache.commons.logging.LogFactory;
 import org.apache.commons.logging.Log;

 public class Activator
         implements BundleActivator
 {
     public void start( BundleContext context ) throws Exception
     {
         LogFactory.getFactory().setBundleContext( context );
     }
 }
 

Author:
Niclas Hedhman (responsible for the OSGi adaptation.), Craig R. McClanahan, Costin Manolache, Richard A. Sitze

Field Summary
static java.lang.String FACTORY_DEFAULT
          The fully qualified class name of the fallback LogFactory implementation class to use, if no other can be found.
static java.lang.String FACTORY_PROPERTIES
          The name of the properties file to search for.
static java.lang.String FACTORY_PROPERTY
          ps4j/pax/logging/providers The name of the property used to identify the LogFactory implementation class name.
 
Constructor Summary
LogFactory()
           
 
Method Summary
static void dispose()
          Pax Logging internal method.
 java.lang.Object getAttribute(java.lang.String name)
          Return the configuration attribute with the specified name (if any), or null if there is no such attribute.
 java.lang.String[] getAttributeNames()
          Return an array containing the names of all currently defined configuration attributes.
static LogFactory getFactory()
           
 Log getInstance(java.lang.Class clazz)
          Convenience method to derive a name from the specified class and call getInstance(String) with it.
 Log getInstance(java.lang.String name)
           Construct (if necessary) and return a Log instance, using the factory's current set of configuration attributes.
static Log getLog(java.lang.Class clazz)
          Convenience method to return a named logger, without the application having to care about factories.
static Log getLog(java.lang.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(java.lang.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(java.lang.String name)
          Remove any configuration attribute associated with the specified name.
 void setAttribute(java.lang.String name, java.lang.Object value)
          Set the configuration attribute with the specified name.
static void setBundleContext(org.osgi.framework.BundleContext ctx)
           
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

FACTORY_PROPERTY

public static final java.lang.String FACTORY_PROPERTY
ps4j/pax/logging/providers The name of the property used to identify the LogFactory implementation class name.

See Also:
Constant Field Values

FACTORY_DEFAULT

public static final java.lang.String FACTORY_DEFAULT
The fully qualified class name of the fallback LogFactory implementation class to use, if no other can be found.

See Also:
Constant Field Values

FACTORY_PROPERTIES

public static final java.lang.String FACTORY_PROPERTIES
The name of the properties file to search for.

See Also:
Constant Field Values
Constructor Detail

LogFactory

public LogFactory()
Method Detail

setBundleContext

public static void setBundleContext(org.osgi.framework.BundleContext ctx)

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(java.lang.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(java.lang.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(java.lang.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 java.lang.Object getAttribute(java.lang.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 java.lang.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(java.lang.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(java.lang.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(java.lang.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(java.lang.String name,
                         java.lang.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

dispose

public static void dispose()
Pax Logging internal method. Should never be used directly.



Copyright © 2006-2011 OPS4J - Open Participation Software for Java. All Rights Reserved.