Logger class is used to log out information. It provides named methods to log information out at the desired level. Each Logger will log information out for a log category that is settable.
@exclude
This class allows us to isolate all our logging dependencies in one place. It also allows us to have zero runtime 3rd party logging jar dependencies, since we default to JUL by default.
By default logging will occur using JUL (Java-Util-Logging). The logging configuration file (logging.properties) used by JUL will taken from the default logging.properties in the JDK installation if no {@code java.util.logging.config.file} systemproperty is set. The {@code vertx-java / vertx-ruby / etc} scripts set {@code java.util.logging.config.file} to point at the logging.propertiesin the vertx distro install directory. This in turn configures vertx to log to a file in a directory called vertx-logs in the users home directory.
If you would prefer to use Log4J or SLF4J instead of JUL then you can set a system property called {@code io.vertx.logger-delegate-factory-class-name} to the class name of the delegate for your logging system.For Log4J the value is {@code io.vertx.core.logging.impl.Log4JLogDelegateFactory}, for SLF4J the value is {@code io.vertx.core.logging.impl.SLF4JLogDelegateFactory}. You will need to ensure whatever jar files required by your favourite log framework are on your classpath.
@author Tim Fox SEVERE (highest value)
WARNING
INFO
CONFIG
FINE
FINER
FINEST (lowest value)
In addition, there is a level OFF that can be used to turn off logging, and a level ALL that can be used to enable logging of all messages.
Notice that re-definition of logging levels was necessary in order to allow portability of calling code in PersonalJava e MIDP environments.
For instance, in order to log the warning message "Attention!", the following code should be used, independently of the target device:
Logger logger = Logger.getJADELogger(this.getClass().getName());
if (logger.isLoggable(logger.WARNING))
logger.log(Logger.WARNING,"Attention!");
Notice that the test isLoggable allows just to improve performance, but it has no side-effect.
J2SE
The J2SE implementation is a pure extension of the java.util.logging.Logger class and it provides the whole set of functionalities of java.util.logging.
In the J2SE environment, the logging configuration can be initialized by using a logging configuration file that will be read at startup. This file is in standard java.util.Properties format. The default logging configuration, that is part of the JRE distribution, can be overridden by setting the java.util.logging.config.file system property, like the following example:
java -Djava.util.logging.config.file=mylogging.properties jade.Boot
PersonaJava
In the PJava implementation of the Logger class (available in the LEAP add-on) calls to the log() method result in calls to System.out.println(). Alternatively it is possible to redirect logging printouts to a text file by setting the -jade_util_Logger_logfile option. Note that, in order to face resource limitations, it is not possible to redirect logging printouts produced by different Logger objects to different files.
MIDP
In the MIDP implementation of the Logger class (available in the LEAP add-on) logging printouts are redirected to a MIDP RecordStore so that they can be later viewed by means of the jade.util.leap.OutputViewer MIDlet included in the LEAP add-on.
The default level for logging is set to INFO, all messages of higher level will be logged by default. In MIDP and PJava the logging level for a Logger object registererd with name x.y.z can be configured by setting the configuration option x_y_z_loglevel to one of severe, warning, info, config, fine, finer, finest, all. See the LEAP user guide for details about how to set JADE configuration options in MIDP and PJava.
@author Rosalba Bochicchio - TILAB
@author Nicolas Lhuillier - Motorola (MIDP version)
Logger objects may be obtained by calls on one of the getLogger factory methods. These will either create a new Logger or return a suitable existing Logger.
Logging messages will be forwarded to registered Handler objects, which can forward the messages to a variety of destinations, including consoles, files, OS logs, etc.
Each Logger keeps track of a "parent" Logger, which is its nearest existing ancestor in the Logger namespace.
Each Logger has a "Level" associated with it. This reflects a minimum Level that this logger cares about. If a Logger's level is set to null, then its effective level is inherited from its parent, which may in turn obtain it recursively from its parent, and so on up the tree.
The log level can be configured based on the properties from the logging configuration file, as described in the description of the LogManager class. However it may also be dynamically changed by calls on the Logger.setLevel method. If a logger's level is changed the change may also affect child loggers, since any child logger that has null as its level will inherit its effective level from its parent.
On each logging call the Logger initially performs a cheap check of the request level (e.g. SEVERE or FINE) against the effective log level of the logger. If the request level is lower than the log level, the logging call returns immediately.
After passing this initial (cheap) test, the Logger will allocate a LogRecord to describe the logging message. It will then call a Filter (if present) to do a more detailed check on whether the record should be published. If that passes it will then publish the LogRecord to its output Handlers. By default, loggers also publish to their parent's Handlers, recursively up the tree.
Each Logger may have a ResourceBundle name associated with it. The named bundle will be used for localizing logging messages. If a Logger does not have its own ResourceBundle name, then it will inherit the ResourceBundle name from its parent, recursively up the tree.
Most of the logger output methods take a "msg" argument. This msg argument may be either a raw value or a localization key. During formatting, if the logger has (or inherits) a localization ResourceBundle and if the ResourceBundle has a mapping for the msg string, then the msg string is replaced by the localized value. Otherwise the original msg string is used. Typically, formatters use java.text.MessageFormat style formatting to format parameters, so for example a format string "{0} {1}" would format two parameters as strings.
When mapping ResourceBundle names to ResourceBundles, the Logger will first try to use the Thread's ContextClassLoader. If that is null it will try the SystemClassLoader instead. As a temporary transition feature in the initial implementation, if the Logger is unable to locate a ResourceBundle from the ContextClassLoader or SystemClassLoader the Logger will also search up the class stack and use successive calling ClassLoaders to try to locate a ResourceBundle. (This call stack search is to allow containers to transition to using ContextClassLoaders and is likely to be removed in future versions.)
Formatting (including localization) is the responsibility of the output Handler, which will typically call a Formatter.
Note that formatting need not occur synchronously. It may be delayed until a LogRecord is actually written to an external sink.
The logging methods are grouped in five main categories:
There are a set of "log" methods that take a log level, a message string, and optionally some parameters to the message string.
There are a set of "logp" methods (for "log precise") that are like the "log" methods, but also take an explicit source class name and method name.
There are a set of "logrb" method (for "log with resource bundle") that are like the "logp" method, but also take an explicit resource bundle name for use in localizing the log message.
There are convenience methods for tracing method entries (the "entering" methods), method returns (the "exiting" methods) and throwing exceptions (the "throwing" methods).
Finally, there are a set of convenience methods for use in the very simplest cases, when a developer simply wants to log a simple string at a given log level. These methods are named after the standard Level names ("severe", "warning", "info", etc.) and take a single argument, a message string.
For the methods that do not take an explicit source name and method name, the Logging framework will make a "best effort" to determine which class and method called into the logging method. However, it is important to realize that this automatically inferred information may only be approximate (or may even be quite wrong!). Virtual machines are allowed to do extensive optimizations when JITing and may entirely remove stack frames, making it impossible to reliably locate the calling class and method.
All methods on Logger are multi-thread safe.
Subclassing Information: Note that a LogManager class may provide its own implementation of named Loggers for any point in the namespace. Therefore, any subclasses of Logger (unless they are implemented in conjunction with a new LogManager class) should take care to obtain a Logger instance from the LogManager class and should delegate operations such as "isLoggable" and "log(LogRecord)" to that instance. Note that in order to intercept all logging output, subclasses need only override the log(LogRecord) method. All the other logging methods are implemented as calls on this log(LogRecord) method. @version 1.50, 07/11/08 @since 1.4
This Logger class represents ServiceTracker for LogService. It provides methods for logging messages. If LogService is not available it logs to stdout.
@see org.osgi.service.log.LogService @see org.osgi.util.tracker.ServiceTracker @version $Rev: 920877 $ $Date: 2010-03-09 08:58:54 -0500 (Tue, 09 Mar 2010) $LogService. This class is in many ways similar to the one used in the system bundle for that same purpose.
@author Felix Project Team
This class mimics the standard OSGi LogService interface. An instance of this class is used by the framework for all logging. By default this class logs messages to standard out. The log level can be set to control the amount of logging performed, where a higher number results in more logging. A log level of zero turns off logging completely.
The log levels match those specified in the OSGi Log Service (i.e., 1 = error, 2 = warning, 3 = information, and 4 = debug). The default value is 1.
This class also uses the System Bundle's context to track log services and will use the highest ranking log service, if present, as a back end instead of printing to standard out. The class uses reflection to invoking the log service's method to avoid a dependency on the log interface.
This class mimics the standard OSGi LogService interface. An instance of this class is used by the framework for all logging. By default this class logs messages to standard out. The log level can be set to control the amount of logging performed, where a higher number results in more logging. A log level of zero turns off logging completely.
The log levels match those specified in the OSGi Log Service (i.e., 1 = error, 2 = warning, 3 = information, and 4 = debug). The default value is 1.
This class also uses the System Bundle's context to track log services and will use the highest ranking log service, if present, as a back end instead of printing to standard out. The class uses reflection to invoking the log service's method to avoid a dependency on the log interface.
This class is a minimal implementation of the original org.apache.log4j.Logger class (as found in log4j 1.2) delegating all calls to a {@link org.slf4j.Logger} instance.
Uh, we need better javadoc here (Rafal)
@author Tomasz Zielinski
@author Jon S. Stevens
@version $Id$
Logger is a component used to log messages. This interface defines the standard way for UIMA components to produce log output. In the UIMA SDK, this interface is implemented using the Java 1.4 logger as a back end. If you want to configure the logger, for example to specify the location of the log file and the logging level, you should use the standard Java 1.4 logger properties or the java.util.logging APIs. See the section "Specifying the Logging Configuration" in the Annotator and Analysis Engine Developer's Guide chapter of the UIMA documentation for more information.
LogService.
@ThreadSafe
@see LogService
@since 3.7
This logger augments PrintWriter by adding a prefix to each printed line and optionally a time stamp, enabling easy post-mortem analysis. @author Assaf Arkin @version $Revision: 1.1.1.1 $ $Date: 2003/03/03 07:09:06 $
An extension to the SLF4J {@code Logger} interface, which adds the {@code quiet} and {@code lifecycle} loglevels.
You can obtain a {@code Logger} instance using {@link Logging#getLogger(Class)} or {@link Logging#getLogger(String)}. A {@code Logger} instance is also available through {@link org.gradle.api.Project#getLogger()}, {@link org.gradle.api.Task#getLogger()} and {@link org.gradle.api.Script#getLogger()}.
Log format = type;target;parameter;value;userLocalIP;ip;userId
@author Roberto Velasco @see org.hdiv.logs.IUserDataImplements a storage manager wrapper that provides a consistent, always available interface to storage management for the Database class, despite the fact not all Database objects actually use file storage.
@author Fred Toussi (fredt@users dot sourceforge.net) @version 1.9.0 @since 1.7.0
Implements a storage manager wrapper that provides a consistent, always available interface to storage management for the Database class, despite the fact not all Database objects actually use file storage.
The Logger class makes it possible to avoid testing for a null Log Database attribute again and again, in many different places, and generally avoids tight coupling between Database and Log, opening the doors for multiple logs/caches in the future. In this way, the Database class does not need to know the details of the Logging/Cache implementation, lowering its breakability factor and promoting long-term code flexibility. @author Fred Toussi (fredt@users dot sourceforge.net) @version 1.9.0 @since 1.7.0
Only exposes the relevent factory and logging methods.
For JBoss the logging should be done as follows:
@Resource Logger logger = Logger.NULL; The above will get you a null-safe instance of Logger. If configured, this logger will be swapped with a real Logger implementation with category set to the current class name. This is done post-object construction, so do not attempt to use these loggers in your constructor. If you wish to initialize loggers like these yourself, do not use the @Resource annotation. This implementation first checks to see if the level is enabled before issuing the log command. In other words, don't do the following if (logger.isTraceEnabled()) logger.trace("message");.
@author Adrian Cole
Log files have a configured maximum size. When a file has reached the configured capacity, Logger switches to the next available alternate file. Normally, log files are created in advance to guarantee that space is available during execution.
Each log file has a file header containing information allowing Logger to reposition and replay the logs during a recovery scenario.
LogFile marking
The LogFile's mark is the the position within the file of the oldest active entry. Initially the mark is set at the beginning of the file. At some configured interval, the caller invokes mark() with the key of the oldest active entry in the log.
For XA the key would be for the oldest transaction still in committing state. In theory, XA could call mark() every time a DONE record is logged. In practice, it should only be necessary to call mark() every minute or so depending on the capacity of the log files.
The Logger maintains an active mark within the set of log files. A file may be reused only if the mark does not reside within the file. The Logger will throw LogFileOverflowException if an attempt is made to switch to a file that contains a mark. @author Michael Giroux
import org.slf4j.Logger; import org.slf4j.LoggerFactory; public class Wombat { final static Logger logger = LoggerFactory.getLogger(Wombat.class); Integer t; Integer oldT; public void setTemperature(Integer temperature) { oldT = t; t = temperature; logger.debug("Temperature set to {}. Old temperature was {}.", t, oldT); if(temperature.intValue() > 50) { logger.info("Temperature has risen above 50 degrees."); } } }
@author Ceki Gülcü
This class allows us to isolate all our logging dependencies in one place. It also allows us to have zero runtime 3rd party logging jar dependencies, since we default to JUL by default.
By default logging will occur using JUL (Java-Util-Logging). The logging configuration file (logging.properties) used by JUL will taken from the default logging.properties in the JDK installation if no {@code java.util.logging.config.file} systemproperty is set. The {@code vertx-java / vertx-ruby / etc} scripts set {@code java.util.logging.config.file} to point at the logging.propertiesin the vertx distro install directory. This in turn configures vertx to log to a file in a directory called vertx-logs in the users home directory.
If you would prefer to use Log4J or SLF4J instead of JUL then you can set a system property called {@code org.vertx.logger-delegate-factory-class-name} to the class name of the delegate for your logging system.For Log4J the value is {@code org.vertx.java.core.logging.Log4JLogDelegateFactory}, for SLF4J the value is {@code org.vertx.java.core.logging.SLF4JLogDelegateFactory}. You will need to ensure whatever jar files required by your favourite log framework are on your classpath.
@author Tim Fox | |