Class LogFactoryImpl
LogFactory that implements the
 following algorithm to dynamically select a logging implementation
 class to instantiate a wrapper for:
 - Use a factory configuration attribute named
     org.apache.commons.logging.Logto identify the requested implementation class.
- Use the org.apache.commons.logging.Logsystem property to identify the requested implementation class.
- If Log4J is available, return an instance of
     org.apache.commons.logging.impl.Log4JLogger.
- If JDK 1.4 or later is available, return an instance of
     org.apache.commons.logging.impl.Jdk14Logger.
- Otherwise, return an instance of
     org.apache.commons.logging.impl.SimpleLog.
 If the selected Log implementation class has a
 setLogFactory() method that accepts a LogFactory
 parameter, this method will be called on each newly created instance
 to identify the associated factory.  This makes factory configuration
 attributes available to the Log instance, if it so desires.
 
 This factory will remember previously created Log instances
 for the same name, and will return them on repeated requests to the
 getInstance() method.
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Field SummaryFieldsModifier and TypeFieldDescriptionstatic final StringThe name (org.apache.commons.logging.Log.allowFlawedContext) of the system property which can be set true/false to determine system behavior when a bad context class loader is encountered.static final StringThe name (org.apache.commons.logging.Log.allowFlawedDiscovery) of the system property which can be set true/false to determine system behavior when a bad logging adapter class is encountered during logging discovery.static final StringThe name (org.apache.commons.logging.Log.allowFlawedHierarchy) of the system property which can be set true/false to determine system behavior when a logging adapter class is encountered which has bound to the wrong Log class implementation.Configuration attributes.TheLoginstances that have already been created, keyed by logger name.static final StringThe name (org.apache.commons.logging.Log) of the system property identifying ourLogimplementation class.protected static final StringThe deprecated system property used for backwards compatibility with old versions of JCL.protected Constructor<?> The one-argument constructor of theLogimplementation class that will be used to create new instances.protected Class<?>[]The signature of the Constructor to be used.protected MethodThe one-argumentsetLogFactorymethod of the selectedLogmethod, if it exists.protected Class<?>[]The signature of thesetLogFactorymethod to be used.Fields inherited from class org.apache.commons.logging.LogFactoryDIAGNOSTICS_DEST_PROPERTY, factories, FACTORY_DEFAULT, FACTORY_PROPERTIES, FACTORY_PROPERTY, HASHTABLE_IMPLEMENTATION_PROPERTY, nullClassLoaderFactory, PRIORITY_KEY, SERVICE_ID, TCCL_KEY
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Constructor SummaryConstructorsConstructorDescriptionPublic no-arguments constructor required by the lookup mechanism.
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Method SummaryModifier and TypeMethodDescriptiongetAttribute(String name) Gets the configuration attribute with the specified name (if any), ornullif there is no such attribute.String[]Gets an array containing the names of all currently defined configuration attributes.protected static ClassLoadergetClassLoader(Class<?> clazz) Workaround for bug in Java1.2; in theory this method is not needed.protected static ClassLoaderGets the context ClassLoader.getInstance(Class<?> clazz) Convenience method to derive a name from the specified class and callgetInstance(String)with it.getInstance(String name) Construct (if necessary) and return aLoginstance, using the factory's current set of configuration attributes.protected StringDeprecated.Never invoked by this class; subclasses should not assume it will be.protected Constructor<?> Deprecated.Never invoked by this class; subclasses should not assume it will be.protected static booleanWorkaround for bug in Java1.2; in theory this method is not needed.protected booleanDeprecated.Never invoked by this class; subclasses should not assume it will be.protected booleanDeprecated.Never invoked by this class; subclasses should not assume it will be.protected booleanDeprecated.Never invoked by this class; subclasses should not assume it will be.protected voidlogDiagnostic(String msg) Output a diagnostic message to a user-specified destination (if the user has enabled diagnostic logging).protected LognewInstance(String name) Create and return a newLoginstance for the specified name.voidrelease()Release any internal references to previously createdLoginstances returned by this factory.voidremoveAttribute(String name) Remove any configuration attribute associated with the specified name.voidsetAttribute(String name, Object value) Sets the configuration attribute with the specified name.Methods inherited from class org.apache.commons.logging.LogFactorycreateFactory, directGetContextClassLoader, getFactory, getLog, getLog, handleThrowable, logRawDiagnostic, newFactory, newFactory, objectId, release, releaseAll
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Field Details- 
LOG_PROPERTYThe name (org.apache.commons.logging.Log) of the system property identifying ourLogimplementation class.- See Also:
 
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LOG_PROPERTY_OLDThe deprecated system property used for backwards compatibility with old versions of JCL.- See Also:
 
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ALLOW_FLAWED_CONTEXT_PROPERTYThe name (org.apache.commons.logging.Log.allowFlawedContext) of the system property which can be set true/false to determine system behavior when a bad context class loader is encountered. When set to false, a LogConfigurationException is thrown if LogFactoryImpl is loaded via a child class loader of the TCCL (this should never happen in sane systems). Default behavior: true (tolerates bad context class loaders) See also method setAttribute.- See Also:
 
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ALLOW_FLAWED_DISCOVERY_PROPERTYThe name (org.apache.commons.logging.Log.allowFlawedDiscovery) of the system property which can be set true/false to determine system behavior when a bad logging adapter class is encountered during logging discovery. When set to false, an exception will be thrown and the app will fail to start. When set to true, discovery will continue (though the user might end up with a different logging implementation than they expected).Default behavior: true (tolerates bad logging adapters) See also method setAttribute. - See Also:
 
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ALLOW_FLAWED_HIERARCHY_PROPERTYThe name (org.apache.commons.logging.Log.allowFlawedHierarchy) of the system property which can be set true/false to determine system behavior when a logging adapter class is encountered which has bound to the wrong Log class implementation. When set to false, an exception will be thrown and the app will fail to start. When set to true, discovery will continue (though the user might end up with a different logging implementation than they expected).Default behavior: true (tolerates bad Log class hierarchy) See also method setAttribute. - See Also:
 
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attributesConfiguration attributes.
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instancesTheLoginstances that have already been created, keyed by logger name.
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logConstructorThe one-argument constructor of theLogimplementation class that will be used to create new instances. This value is initialized bygetLogConstructor(), and then returned repeatedly.
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logConstructorSignatureThe signature of the Constructor to be used.
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logMethodThe one-argumentsetLogFactorymethod of the selectedLogmethod, if it exists.
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logMethodSignatureThe signature of thesetLogFactorymethod to be used.
 
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Constructor Details- 
LogFactoryImplpublic LogFactoryImpl()Public no-arguments constructor required by the lookup mechanism.
 
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Method Details- 
getClassLoaderWorkaround for bug in Java1.2; in theory this method is not needed.LogFactory.getClassLoader(Class).- Parameters:
- clazz- See- LogFactory.getClassLoader(Class).
- Returns:
- See LogFactory.getClassLoader(Class).
- Since:
- 1.1
 
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getContextClassLoaderGets the context ClassLoader. This method is a workaround for a Java 1.2 compiler bug.- Returns:
- the context ClassLoader
- Throws:
- LogConfigurationException
- Since:
- 1.1
 
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isDiagnosticsEnabledWorkaround for bug in Java1.2; in theory this method is not needed.- Returns:
- Same as LogFactory.isDiagnosticsEnabled().
- See Also:
 
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getAttributeGets the configuration attribute with the specified name (if any), ornullif there is no such attribute.- Specified by:
- getAttributein class- LogFactory
- Parameters:
- name- Name of the attribute to return
- Returns:
- the configuration attribute with the specified name.
 
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getAttributeNamesGets an array containing the names of all currently defined configuration attributes. If there are no such attributes, a zero length array is returned.- Specified by:
- getAttributeNamesin class- LogFactory
- Returns:
- an array containing the names of all currently defined configuration attributes
 
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getInstanceConvenience method to derive a name from the specified class and callgetInstance(String)with it.- Specified by:
- getInstancein class- LogFactory
- Parameters:
- clazz- Class for which a suitable Log name will be derived
- Returns:
- a name from the specified class.
- Throws:
- LogConfigurationException- if a suitable- Loginstance cannot be returned
 
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getInstanceConstruct (if necessary) and return a Loginstance, using the factory's current set of configuration attributes.NOTE - Depending upon the implementation of the LogFactoryyou are using, theLoginstance 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.- Specified by:
- getInstancein class- LogFactory
- Parameters:
- name- Logical name of the- Loginstance to be returned (the meaning of this name is only known to the underlying logging implementation that is being wrapped)
- Returns:
- a Loginstance.
- Throws:
- LogConfigurationException- if a suitable- Loginstance cannot be returned
 
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getLogClassNameDeprecated.Never invoked by this class; subclasses should not assume it will be.Gets the fully qualified Java class name of theLogimplementation we will be using.- Returns:
- the fully qualified Java class name of the Logimplementation we will be using.
 
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getLogConstructorDeprecated.Never invoked by this class; subclasses should not assume it will be.Gets the Constructorthat can be called to instantiate newLoginstances.IMPLEMENTATION NOTE - Race conditions caused by calling this method from more than one thread are ignored, because the same Constructorinstance will ultimately be derived in all circumstances.- Returns:
- the Constructorthat can be called to instantiate newLoginstances.
- Throws:
- LogConfigurationException- if a suitable constructor cannot be returned
 
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isJdk13LumberjackAvailableDeprecated.Never invoked by this class; subclasses should not assume it will be.Tests whether JDK 1.3 with Lumberjack logging available.- Returns:
- whether JDK 1.3 with Lumberjack logging available.
 
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isJdk14AvailableDeprecated.Never invoked by this class; subclasses should not assume it will be.Teststruewhether JDK 1.4 or later logging is available. Also checks that theThrowableclass supportsgetStackTrace(), which is required by Jdk14Logger.- Returns:
- Whether JDK 1.4 or later logging is available.
 
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isLog4JAvailableDeprecated.Never invoked by this class; subclasses should not assume it will be.Tests whether a Log4J implementation available.- Returns:
- whether a Log4J implementation available.
 
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logDiagnosticOutput a diagnostic message to a user-specified destination (if the user has enabled diagnostic logging).- Parameters:
- msg- diagnostic message
- Since:
- 1.1
 
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newInstanceCreate and return a newLoginstance for the specified name.- Parameters:
- name- Name of the new logger
- Returns:
- a new Log
- Throws:
- LogConfigurationException- if a new instance cannot be created
 
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releaseRelease any internal references to previously createdLoginstances 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.- Specified by:
- releasein class- LogFactory
 
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removeAttributeRemove any configuration attribute associated with the specified name. If there is no such attribute, no action is taken.- Specified by:
- removeAttributein class- LogFactory
- Parameters:
- name- Name of the attribute to remove
 
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setAttributeSets the configuration attribute with the specified name. Calling this with anullvalue is equivalent to callingremoveAttribute(name).This method can be used to set logging configuration programmatically rather than via system properties. It can also be used in code running within a container (such as a webapp) to configure behavior on a per-component level instead of globally as system properties would do. To use this method instead of a system property, call LogFactory.getFactory().setAttribute(...) This must be done before the first Log object is created; configuration changes after that point will be ignored.This method is also called automatically if LogFactory detects a commons-logging.properties file; every entry in that file is set automatically as an attribute here. - Specified by:
- setAttributein class- LogFactory
- Parameters:
- name- Name of the attribute to set
- value- Value of the attribute to set, or- nullto remove any setting for this attribute
 
 
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