js.log

Class LogFactory

java.lang.Object

js.log.LogFactory

public final class LogFactory
extends Object

Logging system facade. To simplify integration log factory is a utility class; it provides static methods and is not instantiable. Log factory has a static reference to logger provider that is initialized at this class loading. If no implementation found on run-time, provider is initialized with DefaultLogProvider. Provider instance is delegated for most of this factory tasks.

Before to be used, a logging provider may require configuration. It is highly probable but still configuration step is not mandatory. For configuration, log factory has config(Config) that just passes configuration object to provider. Configuration object structure is provider implementation detail. Provider is encourage to initialize itself with sensible default configuration in case user code fails to invoke config(Config).

Log factory main job is to create named logger instances and for that delegates LogProvider.getLogger(String). There is also a convenient factory method to create logger per class, getLog(Class). In fact this is most common usage pattern: every class has its own logger instance, see sample code.

 public class Sample {
        private static final Log log = LogFactory.getLog(Sample.class);
        ...
 }
 

Version:

final

Author:

Iulian Rotaru

Field Summary

Fields

Modifier and Type	Field and Description
private static LogProvider	provider Logger implementation provider.

Constructor Summary

Constructors

Modifier	Constructor and Description
private	LogFactory() Prevent default constructor synthesis.

Method Summary

Modifier and Type	Method and Description
static void	config(Config config) Configure logging provider from configuration object.
static Log	getLog(Class<?> targetClass) Create logger for given class.
static Log	getLog(String loggerName) Create a named logger.
static LogContext	getLogContext() Get logger context usable to bind diagnostic data to current thread.
private static LogProvider	provider() Load log provider from Java services and return the first instance found.

Methods inherited from class java.lang.Object

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

Field Detail

provider

private static LogProvider provider

Logger implementation provider.

Constructor Detail

LogFactory

private LogFactory()

Prevent default constructor synthesis.

Method Detail

provider

private static LogProvider provider()

Load log provider from Java services and return the first instance found. It is expected to have only one log service provider deployed on runtime; it more found just blindly select the first found.

Returns DefaultLogProvider if no log provider service found.

Returns:

log provider instance.

config

public static void config(Config config)

Configure logging provider from configuration object. Configuration object format is entirely under provider control; this method just pass it as it is.

If provider configuration fails, most probably because of bad configuration, reset provider to default.

Parameters:

config - configuration object.

getLog

public static Log getLog(String loggerName)

Create a named logger. By convention logger name is the name of the class for which it is created. This method is here for completeness and expected to be used in special cases. This method delegates LogProvider.getLogger(String).

Parameters:

loggerName - logger name.

Returns:

newly created logger.

getLog

public static Log getLog(Class<?> targetClass)

Create logger for given class. This method just delegates LogProvider.getLogger(String) with class name as argument.

Parameters:

targetClass - class to create logger for.

Returns:

newly created class logger.

getLogContext

public static LogContext getLogContext()

Get logger context usable to bind diagnostic data to current thread.

Returns:

logger diagnostic context.