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org.apache.commons.logging
public interface: Log [javadoc | source]

All Known Implementing Classes:
    Log4JCategoryLog, Log4JLogger, DecoratedSimpleLog, Jdk13LumberjackLogger, NoOpLog, Jdk14Logger, SimpleLog, LogKitLogger, AvalonLogger

A simple logging interface abstracting logging APIs. In order to be instantiated successfully by LogFactory , classes that implement this interface must have a constructor that takes a single String parameter representing the "name" of this Log.

The six logging levels used by Log are (in order):

  1. trace (the least serious)
  2. debug
  3. info
  4. warn
  5. error
  6. fatal (the most serious)
The mapping of these log levels to the concepts used by the underlying logging system is implementation dependent. The implemention should ensure, though, that this ordering behaves as expected.

Performance is often a logging concern. By examining the appropriate property, a component can avoid expensive operations (producing information to be logged).

For example, 

if (log.isDebugEnabled()) {
... do something expensive ...
log.debug(theResult);
}

Configuration of the underlying logging system will generally be done external to the Logging APIs, through whatever mechanism is supported by that system.

Method from org.apache.commons.logging.Log Summary:
debug,   debug,   error,   error,   fatal,   fatal,   info,   info,   isDebugEnabled,   isErrorEnabled,   isFatalEnabled,   isInfoEnabled,   isTraceEnabled,   isWarnEnabled,   trace,   trace,   warn,   warn
Method from org.apache.commons.logging.Log Detail:
 public  void debug(Object message)
     Log a message with debug log level. 
 public  void debug(Object message,
    Throwable t)
     Log an error with debug log level. 
 public  void error(Object message)
     Log a message with error log level. 
 public  void error(Object message,
    Throwable t)
     Log an error with error log level. 
 public  void fatal(Object message)
     Log a message with fatal log level. 
 public  void fatal(Object message,
    Throwable t)
     Log an error with fatal log level. 
 public  void info(Object message)
     Log a message with info log level. 
 public  void info(Object message,
    Throwable t)
     Log an error with info log level. 
 public boolean isDebugEnabled()
     Is debug logging currently enabled? 
    


     Call this method to prevent having to perform expensive operations
(for example, String concatenation)
when the log level is more than debug. 
 public boolean isErrorEnabled()
     Is error logging currently enabled? 
    


     Call this method to prevent having to perform expensive operations
(for example, String concatenation)
when the log level is more than error. 
 public boolean isFatalEnabled()
     Is fatal logging currently enabled? 
    


     Call this method to prevent having to perform expensive operations
(for example, String concatenation)
when the log level is more than fatal. 
 public boolean isInfoEnabled()
     Is info logging currently enabled? 
    


     Call this method to prevent having to perform expensive operations
(for example, String concatenation)
when the log level is more than info. 
 public boolean isTraceEnabled()
     Is trace logging currently enabled? 
    


     Call this method to prevent having to perform expensive operations
(for example, String concatenation)
when the log level is more than trace. 
 public boolean isWarnEnabled()
     Is warn logging currently enabled? 
    


     Call this method to prevent having to perform expensive operations
(for example, String concatenation)
when the log level is more than warn. 
 public  void trace(Object message)
     Log a message with trace log level. 
 public  void trace(Object message,
    Throwable t)
     Log an error with trace log level. 
 public  void warn(Object message)
     Log a message with warn log level. 
 public  void warn(Object message,
    Throwable t)
     Log an error with warn log level.