LogFactory (OPS4J Pax Logging

java.lang.Object
- org.apache.commons.logging.LogFactory

```
public class LogFactory
extends 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;
- ensure that commons-logging.jar is NOT included in your bundle jar.
- include the pax-logging-client.jar into the client bundle.
- update your Manifest.MF to import the org.ops4j.pax.logging package.
- Initiate this class by setting the Bundle Context.
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

Fields
Modifier and Type	Field and Description
`static String`	`FACTORY_DEFAULT` The fully qualified class name of the fallback `LogFactory` implementation class to use, if no other can be found.
`static String`	`FACTORY_PROPERTIES` The name of the properties file to search for.
`static String`	`FACTORY_PROPERTY` ps4j/pax/logging/providers The name of the property used to identify the LogFactory implementation class name.

Constructor Summary

Constructors
Constructor and Description

LogFactory()

Constructors
Constructor and Description
`LogFactory()`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`static void`	`dispose()` Pax Logging internal method.
`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.
`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 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 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 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(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
  - dispose
```
public static void dispose()
```
    Pax Logging internal method. Should never be used directly.

Class LogFactory

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

FACTORY_PROPERTY

FACTORY_DEFAULT

FACTORY_PROPERTIES

Constructor Detail

LogFactory

Method Detail

setBundleContext

getFactory

getLog

getLog

release

releaseAll

getAttribute

getAttributeNames

getInstance

getInstance

release

removeAttribute

setAttribute

dispose