| java.lang.Object
 org.apache.juli.logging.LogFactory
| LogFactory | | public class LogFactory (Code) | | Modified LogFactory: removed all discovery, hardcode a specific implementation
If you like a different logging implementation - use either the discovery-based
commons-logging, or better - another implementation hardcoded to your favourite
logging impl.
Why ? Each application and deployment can choose a logging implementation -
that involves configuration, installing the logger jar and optional plugins, etc.
As part of this process - they can as well install the commons-logging implementation
that corresponds to their logger of choice. This completely avoids any discovery
problem, while still allowing the user to switch.
Note that this implementation is not just a wrapper arround JDK logging ( like
the original commons-logging impl ). It adds 2 features - a simpler configuration
( which is in fact a subset of log4j.properties ) and a formatter that is
less ugly.
The removal of 'abstract' preserves binary backward compatibility. It is possible
to preserve the abstract - and introduce another ( hardcoded ) factory - but I
see no benefit.
Since this class is not intended to be extended - and provides
no plugin for other LogFactory implementation - all protected methods are removed.
This can be changed - but again, there is little value in keeping dead code.
Just take a quick look at the removed code ( and it's complexity)
--------------
Original comment:
Factory for creating
Log instances, with discovery and
configuration features similar to that employed by standard Java APIs
such as JAXP.
IMPLEMENTATION NOTE - This implementation is heavily
based on the SAXParserFactory and DocumentBuilderFactory implementations
(corresponding to the JAXP pluggability APIs) found in Apache Xerces.
author:
Craig R. McClanahan
author:
Costin Manolache
author:
Richard A. Sitze
version:
$Revision: 467222 $ $Date: 2006-10-24 05:17:11 +0200 (mar., 24 oct. 2006) $ |
| Method Summary | |
| public Object | getAttribute(String name)
Return the configuration attribute with the specified name (if any),
or null if there is no such attribute. | | public String[] | getAttributeNames()
Return an array containing the names of all currently defined
configuration attributes. | | public static LogFactory | getFactory()
Construct (if necessary) and return a LogFactory
instance, using the following ordered lookup procedure to determine
the name of the implementation class to be loaded.
- The
org.apache.commons.logging.LogFactory system
property.
- The JDK 1.3 Service Discovery mechanism
- Use the properties file
commons-logging.properties
file, if found in the class path of this class. | | public Log | getInstance(String name)
| | public Log | getInstance(Class clazz)
Convenience method to derive a name from the specified class and
call getInstance(String) with it. | | public static Log | getLog(Class clazz)
Convenience method to return a named logger, without the application
having to care about factories. | | public static Log | getLog(String name)
Convenience method to return a named logger, without the application
having to care about factories. | | public static String | objectId(Object o)
Returns a string that uniquely identifies the specified object, including
its class.
The returned string is of form "classname@hashcode", ie is the same as
the return value of the Object.toString() method, but works even when
the specified object's class has overidden the toString method.
Parameters:
o - may be null. | | public void | release()
Release any internal references to previously created
Log instances returned by this factory. | | 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. | | public static void | releaseAll()
Release any internal references to previously created
LogFactory instances, after calling the instance method release() on
each of them. | | public void | removeAttribute(String name)
Remove any configuration attribute associated with the specified name. | | public void | setAttribute(String name, Object value)
Set the configuration attribute with the specified name. | | void | setLogConfig(Properties p)
|
| FACTORY_DEFAULT | | final public static String FACTORY_DEFAULT(Code) | | The fully qualified class name of the fallback LogFactory
implementation class to use, if no other can be found.
|
| FACTORY_PROPERTIES | | final public static String FACTORY_PROPERTIES(Code) | | The name of the properties file to search for.
|
| FACTORY_PROPERTY | | final public static String FACTORY_PROPERTY(Code) | | The name of the property used to identify the LogFactory implementation
class name.
|
| HASHTABLE_IMPLEMENTATION_PROPERTY | | final public static String HASHTABLE_IMPLEMENTATION_PROPERTY(Code) | | Setting this system property value allows the Hashtable used to store
classloaders to be substituted by an alternative implementation.
Note: LogFactory will print:
[ERROR] LogFactory: Load of custom hashtable failed
Usage: Set this property when Java is invoked
and LogFactory will attempt to load a new instance
of the given implementation class.
For example, running the following ant scriplet:
<java classname="${test.runner}" fork="yes" failonerror="${test.failonerror}">
...
<sysproperty
key="org.apache.commons.logging.LogFactory.HashtableImpl"
value="org.apache.commons.logging.AltHashtable"/>
</java>
LogFactory will load an instance of
org.apache.commons.logging.AltHashtable.
A typical use case is to allow a custom
Hashtable implementation using weak references to be substituted.
This will allow classloaders to be garbage collected without
the need to release them (on 1.3+ JVMs only, of course ;)
|
| getAttribute | | public Object getAttribute(String name)(Code) | | 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 |
| getAttributeNames | | public String[] getAttributeNames()(Code) | | Return an array containing the names of all currently defined
configuration attributes. If there are no such attributes, a zero
length array is returned.
|
| getFactory | | public static LogFactory getFactory() throws LogConfigurationException(Code) | | Construct (if necessary) and return a LogFactory
instance, using the following ordered lookup procedure to determine
the name of the implementation class to be loaded.
- The
org.apache.commons.logging.LogFactory system
property.
- The JDK 1.3 Service Discovery mechanism
- Use the properties file
commons-logging.properties
file, if found in the class path of this class. The configuration
file is in standard java.util.Properties format and
contains the fully qualified name of the implementation class
with the key being the system property defined above.
- Fall back to a default implementation class
(
org.apache.commons.logging.impl.LogFactoryImpl).
NOTE - If the properties file method of identifying the
LogFactory implementation class is utilized, all of the
properties defined in this file will be set as configuration attributes
on the corresponding LogFactory instance.
exception:
LogConfigurationException - if the implementation class is notavailable or cannot be instantiated. |
| getInstance | | public Log getInstance(String name) throws LogConfigurationException(Code) | | 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 bereturned (the meaning of this name is only known to the underlyinglogging implementation that is being wrapped)
exception:
LogConfigurationException - if a suitable Loginstance cannot be returned |
| getInstance | | public Log getInstance(Class clazz) throws LogConfigurationException(Code) | | 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
exception:
LogConfigurationException - if a suitable Loginstance cannot be returned |
| getLog | | public static Log getLog(Class clazz) throws LogConfigurationException(Code) | | 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
exception:
LogConfigurationException - if a suitable Loginstance cannot be returned |
| getLog | | public static Log getLog(String name) throws LogConfigurationException(Code) | | Convenience method to return a named logger, without the application
having to care about factories.
Parameters:
name - Logical name of the Log instance to bereturned (the meaning of this name is only known to the underlyinglogging implementation that is being wrapped)
exception:
LogConfigurationException - if a suitable Loginstance cannot be returned |
| objectId | | public static String objectId(Object o)(Code) | | Returns a string that uniquely identifies the specified object, including
its class.
The returned string is of form "classname@hashcode", ie is the same as
the return value of the Object.toString() method, but works even when
the specified object's class has overidden the toString method.
Parameters:
o - may be null. a string of form classname@hashcode, or "null" if param o is null. |
| release | | public void release()(Code) | | 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.
|
| release | | public static void release(ClassLoader classLoader)(Code) | | 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()(Code) | | 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.
|
| removeAttribute | | public void removeAttribute(String name)(Code) | | 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)(Code) | | 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
Parameters:
value - Value of the attribute to set, or nullto remove any setting for this attribute |
|
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