Class LogFactory
- java.lang.Object
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- org.apache.juli.logging.LogFactory
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public class LogFactory extends java.lang.Object
This is a modified LogFactory that uses a simpleServiceLoader
based discovery mechanism with a default of using JDK based logging. An implementation that uses the full Commons Logging discovery mechanism is available as part of the Tomcat extras download. Why? It is an attempt to strike a balance between simpler code (no discovery) and providing flexibility - particularly for those projects that embed Tomcat or some of Tomcat's components - is an alternative logging implementation is desired. Note that this implementation is not just a wrapper around 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 - 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, Costin Manolache, Richard A. Sitze
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description static LogFactory
getFactory()
Construct (if necessary) and return aLogFactory
instance, using the following ordered lookup procedure to determine the name of the implementation class to be loaded.Log
getInstance(java.lang.Class<?> clazz)
Convenience method to derive a name from the specified class and callgetInstance(String)
with it.Log
getInstance(java.lang.String name)
Construct (if necessary) and return aLog
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(java.lang.ClassLoader classLoader)
Release any internal references to previously createdLogFactory
instances that have been associated with the specified class loader (if any), after calling the instance methodrelease()
on each of them.
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Method Detail
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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, theLog
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 theLog
instance to be returned (the meaning of this name is only known to the underlying logging implementation that is being wrapped)- Returns:
- A log instance with the requested name
- Throws:
LogConfigurationException
- if a suitableLog
instance cannot be returned
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getInstance
public Log getInstance(java.lang.Class<?> clazz) throws LogConfigurationException
Convenience method to derive a name from the specified class and callgetInstance(String)
with it.- Parameters:
clazz
- Class for which a suitable Log name will be derived- Returns:
- A log instance with a name of clazz.getName()
- Throws:
LogConfigurationException
- if a suitableLog
instance cannot be returned
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getFactory
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 standardjava.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 correspondingLogFactory
instance.- Returns:
- The singleton LogFactory instance
- Throws:
LogConfigurationException
- if the implementation class is not available or cannot be instantiated.
- The
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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:
- A log instance with a name of clazz.getName()
- Throws:
LogConfigurationException
- if a suitableLog
instance cannot be returned
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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 theLog
instance to be returned (the meaning of this name is only known to the underlying logging implementation that is being wrapped)- Returns:
- A log instance with the requested name
- Throws:
LogConfigurationException
- if a suitableLog
instance cannot be returned
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release
public static void release(java.lang.ClassLoader classLoader)
Release any internal references to previously createdLogFactory
instances that have been associated with the specified class loader (if any), after calling the instance methodrelease()
on each of them.- Parameters:
classLoader
- ClassLoader for which to release the LogFactory
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