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org.apache.juli.logging
public class: LogFactory [javadoc | source]
java.lang.Object
   org.apache.juli.logging.LogFactory
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.

Field Summary
public static final  String FACTORY_PROPERTY    The name of the property used to identify the LogFactory implementation class name. 
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. 
public static final  String FACTORY_PROPERTIES    The name of the properties file to search for. 
public static final  String HASHTABLE_IMPLEMENTATION_PROPERTY   

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
to system error and then continue using a standard Hashtable.

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>
will mean that 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 ;)

 
 Properties logConfig     
Method from org.apache.juli.logging.LogFactory Summary:
getAttribute,   getAttributeNames,   getFactory,   getInstance,   getInstance,   getLog,   getLog,   objectId,   release,   release,   releaseAll,   removeAttribute,   setAttribute,   setLogConfig
Methods from java.lang.Object:
clone,   equals,   finalize,   getClass,   hashCode,   notify,   notifyAll,   toString,   wait,   wait,   wait
Method from org.apache.juli.logging.LogFactory Detail:
 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. If there are no such attributes, a zero length array is returned.
 public static LogFactory getFactory() throws LogConfigurationException 

    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.

 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.

 public Log getInstance(Class clazz) throws LogConfigurationException 
    Convenience method to derive a name from the specified class and call getInstance(String) with it.
 public static Log getLog(Class clazz) throws LogConfigurationException 
    Convenience method to return a named logger, without the application having to care about factories.
 public static Log getLog(String name) throws LogConfigurationException 
    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.

 public  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.
 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. 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.
 public  void removeAttribute(String name) 
    Remove any configuration attribute associated with the specified name. If there is no such attribute, no action is taken.
 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).
  void setLogConfig(Properties p)