org.knopflerfish.service.log
Class LogRef

java.lang.Object
  org.knopflerfish.service.log.LogRef

All Implemented Interfaces:

java.util.EventListener, LogService, LogService, ServiceListener

public class LogRef

extends java.lang.Object

implements ServiceListener, LogService

* LogRef is an utility class that simplifies the use of the LogService. * *

* * LogRef let you use the log without worrying about getting new * service objects when the log service is restarted. It also * supplies methods with short names that does logging with all the * different LogService severity types. * *

* * To use the LogRef you need to import * org.knopflerfish.service.log.LogRef and instantiate * LogRef with your bundle context as parameter. The bundle context * is used for getting the LogService and adding a service listener. * *

* *

Example usage

* * The if statement that protects each call to the * LogRef instance below is there to save the effort * required for creating the message string object in cases where the * log will throw away the log entry due to its unimportance. The * user must have this if-test in his code since that is * the only way to avoid constructing the string object. Placing it * in the wrapper (LogRef) will not help due to the design of the Java * programming language. * * *

 * package org.knopflerfish.example.hello; * * import
 org.osgi.framework.*; * import org.knopflerfish.service.log.LogRef; * * *
 public class Hello implements BundleActivator { * LogRef log; * * public void
 start(BundleContext bundleContext) { * log = new LogRef(bundleContext); * if
 (log.doInfo()) log.info("Hello started."); * } * * public void
 stop(BundleContext bundleContext) { * if (log.doDebug()) log.debug("Hello
 stopped."); * } * } *
 
 

* * *

Author:

Gatespace AB *

See Also:

*, LogService

Field Summary

Fields inherited from interface org.osgi.service.log.LogService

LOG_DEBUG, LOG_ERROR, LOG_INFO, LOG_WARNING

Constructor Summary

LogRef(BundleContext bc)
* Create new LogRef object for a given bundle. * * * If the system property org.knopflerfish.log.out equals * "true", system.out will be used as fallback if no log service * is found. * *

LogRef(BundleContext bc, boolean out)
* Create new LogRef object for a given bundle

Method Summary

void	close() * Close this LogRef object.
void	debug(java.lang.String msg) * Log a debug level message * *
void	debug(java.lang.String msg, ServiceReference sr) * Log a debug level message. * *
void	debug(java.lang.String msg, ServiceReference sr, java.lang.Throwable e) * Log a debug level message. * *
void	debug(java.lang.String msg, java.lang.Throwable e) * Log a debug level message. * *
boolean	doDebug() * Returns true if messages with severity debug or higher * are saved by the log
boolean	doError() * Returns true if messages with severity error or higher * are saved by the log
boolean	doInfo() * Returns true if messages with severity info or higher * are saved by the log
protected void	doLog(java.lang.String msg, int level, ServiceReference sr, java.lang.Throwable e) * Sends a message to the log if possible. * *
boolean	doWarn() * Returns true if messages with severity warning or higher * are saved by the log
void	error(java.lang.String msg) * Log an error level message. * *
void	error(java.lang.String msg, ServiceReference sr) * Log an error level message. * *
void	error(java.lang.String msg, ServiceReference sr, java.lang.Throwable e) * Log an error level message. * *
void	error(java.lang.String msg, java.lang.Throwable e) * Log an error level message. * *
int	getLogLevel() * Returns the current log level.
void	info(java.lang.String msg) * Log an info level message. * *
void	info(java.lang.String msg, ServiceReference sr) * Log an info level message. * *
void	info(java.lang.String msg, ServiceReference sr, java.lang.Throwable e) * Log an info level message. * *
void	info(java.lang.String msg, java.lang.Throwable e) * Log an info level message. * *
void	log(int level, java.lang.String message) * Log a message. * The ServiceDescription field and the Throwable * field of the LogEntry will be set to null
void	log(int level, java.lang.String message, java.lang.Throwable exception) * Log a message with an exception. * The ServiceDescription field of the LogEntry will be set to null
void	log(ServiceReference sr, int level, java.lang.String message) * Log a message associated with a specific Service. * The Throwable field of the LogEntry will be set to null
void	log(ServiceReference sr, int level, java.lang.String message, java.lang.Throwable exception) * Log a message with an exception associated with a specific Service
void	serviceChanged(ServiceEvent evt) * Service listener entry point.
void	warn(java.lang.String msg) * Log a warning level message. * *
void	warn(java.lang.String msg, ServiceReference sr) * Log a warning level message. * *
void	warn(java.lang.String msg, ServiceReference sr, java.lang.Throwable e) * Log a warning level message. * *
void	warn(java.lang.String msg, java.lang.Throwable e) * Log a warning level message. * *

Methods inherited from class java.lang.Object

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

Constructor Detail

LogRef

public LogRef(BundleContext bc,
              boolean out)

* Create new LogRef object for a given bundle. *

Parameters:

bc - the bundle context of the bundle that this log ref * instance belongs too. *

out - If true print messages on System.out when * there is no log service.

LogRef

public LogRef(BundleContext bc)

* Create new LogRef object for a given bundle. * *

* If the system property org.knopflerfish.log.out equals * "true", system.out will be used as fallback if no log service * is found. *

*

Parameters:

bc - the bundle context of the bundle that this log ref * instance belongs too.

Method Detail

serviceChanged

public void serviceChanged(ServiceEvent evt)

* Service listener entry point. Releases the log service object if * one has been fetched. * *

Specified by:

serviceChanged in interface ServiceListener

Parameters:

evt - Service event

close

public void close()

* Close this LogRef object. Ungets the log service if active.

doLog

protected void doLog(java.lang.String msg,
                     int level,
                     ServiceReference sr,
                     java.lang.Throwable e)

* Sends a message to the log if possible. * *

Parameters:

msg - Human readable string describing the condition. *

level - The severity of the message (Should be one of the * four predefined severities). *

sr - The ServiceReference of the service * that this message is associated with. *

e - The exception that reflects the condition.

getLogLevel

public int getLogLevel()

* Returns the current log level. There is no use to generate log * entries with a severity level less than this value since such * entries will be thrown away by the log. * *

Specified by:

getLogLevel in interface LogService

Returns:

the current severity log level for this bundle.

doDebug

public boolean doDebug()

* Returns true if messages with severity debug or higher * are saved by the log. *

Returns:

true if messages with severity LOG_DEBUG * or higher are included in the log, otherwise false.

doWarn

public boolean doWarn()

* Returns true if messages with severity warning or higher * are saved by the log. *

Returns:

true if messages with severity LOG_WARNING * or higher are included in the log, otherwise false.

doInfo

public boolean doInfo()

* Returns true if messages with severity info or higher * are saved by the log. *

Returns:

true if messages with severity LOG_INFO * or higher are included in the log, otherwise false.

doError

public boolean doError()

* Returns true if messages with severity error or higher * are saved by the log. *

Returns:

true if messages with severity LOG_ERROR * or higher are included in the log, otherwise false.

debug

public void debug(java.lang.String msg)

* Log a debug level message * *

Parameters:

msg - Log message.

debug

public void debug(java.lang.String msg,
                  ServiceReference sr)

* Log a debug level message. * *

Parameters:

msg - Log message *

sr - The ServiceReference of the service * that this message is associated with.

debug

public void debug(java.lang.String msg,
                  java.lang.Throwable e)

* Log a debug level message. * *

Parameters:

msg - Log message *

e - The exception that reflects the condition.

debug

public void debug(java.lang.String msg,
                  ServiceReference sr,
                  java.lang.Throwable e)

* Log a debug level message. * *

Parameters:

msg - Log message *

sr - The ServiceReference of the service * that this message is associated with. *

e - The exception that reflects the condition.

info

public void info(java.lang.String msg)

* Log an info level message. * *

Parameters:

msg - Log message

info

public void info(java.lang.String msg,
                 ServiceReference sr)

* Log an info level message. * *

Parameters:

msg - Log message *

sr - The ServiceReference of the service * that this message is associated with.

info

public void info(java.lang.String msg,
                 java.lang.Throwable e)

* Log an info level message. * *

Parameters:

msg - Log message *

e - The exception that reflects the condition.

info

public void info(java.lang.String msg,
                 ServiceReference sr,
                 java.lang.Throwable e)

* Log an info level message. * *

Parameters:

msg - Log message *

sr - The ServiceReference of the service * that this message is associated with. *

e - The exception that reflects the condition.

warn

public void warn(java.lang.String msg)

* Log a warning level message. * *

Parameters:

msg - Log message

warn

public void warn(java.lang.String msg,
                 ServiceReference sr)

* Log a warning level message. * *

Parameters:

msg - Log message *

sr - The ServiceReference of the service * that this message is associated with.

warn

public void warn(java.lang.String msg,
                 java.lang.Throwable e)

* Log a warning level message. * *

Parameters:

msg - Log message *

e - The exception that reflects the condition.

warn

public void warn(java.lang.String msg,
                 ServiceReference sr,
                 java.lang.Throwable e)

* Log a warning level message. * *

Parameters:

msg - Log message *

sr - The ServiceReference of the service * that this message is associated with. *

e - The exception that reflects the condition.

error

public void error(java.lang.String msg)

* Log an error level message. * *

Parameters:

msg - Log message

error

public void error(java.lang.String msg,
                  ServiceReference sr)

* Log an error level message. * *

Parameters:

msg - Log message *

sr - The ServiceReference of the service * that this message is associated with.

error

public void error(java.lang.String msg,
                  java.lang.Throwable e)

* Log an error level message. * *

Parameters:

msg - Log message *

e - The exception that reflects the condition.

error

public void error(java.lang.String msg,
                  ServiceReference sr,
                  java.lang.Throwable e)

* Log an error level message. * *

Parameters:

msg - Log message *

sr - The ServiceReference of the service * that this message is associated with. *

e - The exception that reflects the condition.

log

public void log(int level,
                java.lang.String message)

* Log a message. * The ServiceDescription field and the Throwable * field of the LogEntry will be set to null. *

Specified by:

log in interface LogService

Parameters:

level - The severity of the message. (Should be one of the * four predefined severities.) *

message - Human readable string describing the condition.

See Also:

LogService.LOG_ERROR, LogService.LOG_WARNING, LogService.LOG_INFO, LogService.LOG_DEBUG

log

public void log(int level,
                java.lang.String message,
                java.lang.Throwable exception)

* Log a message with an exception. * The ServiceDescription field of the LogEntry will be set to null. *

Specified by:

log in interface LogService

Parameters:

level - The severity of the message. (Should be one of the * four predefined severities.) *

message - Human readable string describing the condition. *

exception - The exception that reflects the condition.

See Also:

LogService.LOG_ERROR, LogService.LOG_WARNING, LogService.LOG_INFO, LogService.LOG_DEBUG

log

public void log(ServiceReference sr,
                int level,
                java.lang.String message)

* Log a message associated with a specific Service. * The Throwable field of the LogEntry will be set to null. *

Specified by:

log in interface LogService

Parameters:

sr - The ServiceReference of the service that * this message is associated with. *

level - The severity of the message. (Should be one of the * four predefined severities.) *

message - Human readable string describing the condition.

See Also:

LogService.LOG_ERROR, LogService.LOG_WARNING, LogService.LOG_INFO, LogService.LOG_DEBUG

log

public void log(ServiceReference sr,
                int level,
                java.lang.String message,
                java.lang.Throwable exception)

* Log a message with an exception associated with a specific Service. *

Specified by:

log in interface LogService

Parameters:

sr - The ServiceReference of the service that * this message is associated with. *

level - The severity of the message. (Should be one of the * four predefined severities.) *

message - Human readable string describing the condition. *

exception - The exception that reflects the condition.

See Also:

LogService.LOG_ERROR, LogService.LOG_WARNING, LogService.LOG_INFO, LogService.LOG_DEBUG