org.apache.commons.logging.impl

Class AndroidLogFactoryImpl

java.lang.Object

org.apache.commons.logging.AndroidLogFactory

org.apache.commons.logging.impl.AndroidLogFactoryImpl

public class AndroidLogFactoryImpl
extends AndroidLogFactory

Concrete subclass of AndroidLogFactory 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.AndroidLog to identify the requested implementation class.
• Use the org.apache.commons.logging.AndroidLog system property to identify the requested implementation class.
• Return an instance of org.apache.commons.logging.impl.SimpleAndroidLog.

If the selected AndroidLog implementation class has a setLogFactory() method that accepts a AndroidLogFactory parameter, this method will be called on each newly created instance to identify the associated factory. This makes factory configuration attributes available to the AndroidLog instance, if it so desires.

This factory will remember previously created AndroidLog instances for the same name, and will return them on repeated requests to the getInstance() method.

Author:

Nicolas Dos Santos

Field Summary

Fields

Modifier and Type	Field and Description
protected Map<String,Object>	attributes Configuration attributes.
protected Map<String,AndroidLog>	instances The AndroidLog instances that have already been created, keyed by logger name.
static String	LOG_PROPERTY The name (org.apache.commons.logging.AndroidLog) of the system property identifying our AndroidLog implementation class.
protected Constructor<?>	logConstructor The one-argument constructor of the AndroidLog implementation class that will be used to create new instances.
protected Class<?>[]	logConstructorSignature The signature of the Constructor to be used.
protected Method	logMethod The one-argument setLogFactory method of the selected AndroidLog method, if it exists.
protected Class<?>[]	logMethodSignature The signature of the setLogFactory method to be used.

Fields inherited from class org.apache.commons.logging.AndroidLogFactory

DIAGNOSTICS_DEST_PROPERTY, factories, FACTORY_DEFAULT, FACTORY_PROPERTIES, FACTORY_PROPERTY, PRIORITY_KEY

Constructor Summary

Constructors

Constructor and Description
AndroidLogFactoryImpl() Public no-arguments constructor required by the lookup mechanism.

Method Summary

Methods

Modifier and Type	Method and Description
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.
protected static ClassLoader	getClassLoader(Class<?> clazz) Workaround for bug in Java1.2; in theory this method is not needed.
AndroidLog	getInstance(Class<?> clazz) Convenience method to derive a name from the specified class and call getInstance(String) with it.
AndroidLog	getInstance(String name) Construct (if necessary) and return a AndroidLog instance, using the factory's current set of configuration attributes.
protected static boolean	isDiagnosticsEnabled() Workaround for bug in Java1.2; in theory this method is not needed.
protected void	logDiagnostic(String msg) Output a diagnostic message to a user-specified destination (if the user has enabled diagnostic logging).
protected AndroidLog	newInstance(String name) Create and return a new AndroidLog instance for the specified name.
void	release() Release any internal references to previously created AndroidLog instances returned by this factory.
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.

Methods inherited from class org.apache.commons.logging.AndroidLogFactory

createFactory, getFactory, getLog, getLog, logRawDiagnostic, newFactory, objectId, release, releaseAll

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

LOG_PROPERTY

public static final String LOG_PROPERTY

The name (org.apache.commons.logging.AndroidLog) of the system property identifying our AndroidLog implementation class.

See Also:

Constant Field Values

attributes

protected Map<String,Object> attributes

Configuration attributes.

instances

protected Map<String,AndroidLog> instances

The AndroidLog instances that have already been created, keyed by logger name.

logConstructor

protected Constructor<?> logConstructor

The one-argument constructor of the AndroidLog implementation class that will be used to create new instances. This value is initialized by getLogConstructor(), and then returned repeatedly.

logConstructorSignature

protected Class<?>[] logConstructorSignature

The signature of the Constructor to be used.

logMethod

protected Method logMethod

The one-argument setLogFactory method of the selected AndroidLog method, if it exists.

logMethodSignature

protected Class<?>[] logMethodSignature

The signature of the setLogFactory method to be used.

Constructor Detail

AndroidLogFactoryImpl

public AndroidLogFactoryImpl()

Public no-arguments constructor required by the lookup mechanism.

Method Detail

getAttribute

public Object getAttribute(String name)

Return the configuration attribute with the specified name (if any), or null if there is no such attribute.

Specified by:

getAttribute in class AndroidLogFactory

Parameters:

name - Name of the attribute to return

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.

Specified by:

getAttributeNames in class AndroidLogFactory

getInstance

public AndroidLog getInstance(Class<?> clazz)
                       throws LogConfigurationException

Convenience method to derive a name from the specified class and call getInstance(String) with it.

Specified by:

getInstance in class AndroidLogFactory

Parameters:

clazz - Class for which a suitable AndroidLog name will be derived

Throws:

LogConfigurationException - if a suitable AndroidLog instance cannot be returned

getInstance

public AndroidLog getInstance(String name)
                       throws LogConfigurationException

Construct (if necessary) and return a AndroidLog instance, using the factory's current set of configuration attributes.

NOTE - Depending upon the implementation of the AndroidLogFactory you are using, the AndroidLog 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.

Specified by:

getInstance in class AndroidLogFactory

Parameters:

name - Logical name of the AndroidLog instance to be returned (the meaning of this name is only known to the underlying logging implementation that is being wrapped)

Throws:

LogConfigurationException - if a suitable AndroidLog instance cannot be returned

release

public void release()

Release any internal references to previously created AndroidLog 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.

Specified by:

release in class AndroidLogFactory

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.

Specified by:

removeAttribute in class AndroidLogFactory

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).

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 behaviour on a per-component level instead of globally as system properties would do. To use this method instead of a system property, call

 AndroidLogFactory.getFactory().setAttribute(...)
 

This must be done before the first AndroidLog object is created; configuration changes after that point will be ignored.

This method is also called automatically if AndroidLogFactory detects a commons-logging.properties file; every entry in that file is set automatically as an attribute here.

Specified by:

setAttribute in class AndroidLogFactory

Parameters:

name - Name of the attribute to set

value - Value of the attribute to set, or null to remove any setting for this attribute

isDiagnosticsEnabled

protected static boolean isDiagnosticsEnabled()

Workaround for bug in Java1.2; in theory this method is not needed. See AndroidLogFactory.isDiagnosticsEnabled.

getClassLoader

protected static ClassLoader getClassLoader(Class<?> clazz)

Workaround for bug in Java1.2; in theory this method is not needed. See AndroidLogFactory.getClassLoader.

Since:

1.1

logDiagnostic

protected void logDiagnostic(String msg)

Output a diagnostic message to a user-specified destination (if the user has enabled diagnostic logging).

Parameters:

msg - diagnostic message

Since:

1.1

newInstance

protected AndroidLog newInstance(String name)
                          throws LogConfigurationException

Create and return a new AndroidLog instance for the specified name.

Parameters:

name - Name of the new logger

Throws:

LogConfigurationException - if a new instance cannot be created