public interface

Log

org.apache.commons.logging.Log
Known Indirect Subclasses

Class Overview

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.

Summary

Public Methods
abstract void debug(Object message, Throwable t)

Log an error with debug log level.

abstract void debug(Object message)

Log a message with debug log level.

abstract void error(Object message)

Log a message with error log level.

abstract void error(Object message, Throwable t)

Log an error with error log level.

abstract void fatal(Object message)

Log a message with fatal log level.

abstract void fatal(Object message, Throwable t)

Log an error with fatal log level.

abstract void info(Object message)

Log a message with info log level.

abstract void info(Object message, Throwable t)

Log an error with info log level.

abstract 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.

abstract 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.

abstract 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.

abstract 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.

abstract 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.

abstract 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.

abstract void trace(Object message)

Log a message with trace log level.

abstract void trace(Object message, Throwable t)

Log an error with trace log level.

abstract void warn(Object message, Throwable t)

Log an error with warn log level.

abstract void warn(Object message)

Log a message with warn log level.

Public Methods

public abstract void debug (Object message, Throwable t)

Log an error with debug log level.

Parameters
message log this message
t log this cause

public abstract void debug (Object message)

Log a message with debug log level.

Parameters
message log this message

public abstract void error (Object message)

Log a message with error log level.

Parameters
message log this message

public abstract void error (Object message, Throwable t)

Log an error with error log level.

Parameters
message log this message
t log this cause

public abstract void fatal (Object message)

Log a message with fatal log level.

Parameters
message log this message

public abstract void fatal (Object message, Throwable t)

Log an error with fatal log level.

Parameters
message log this message
t log this cause

public abstract void info (Object message)

Log a message with info log level.

Parameters
message log this message

public abstract void info (Object message, Throwable t)

Log an error with info log level.

Parameters
message log this message
t log this cause

public abstract 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.

Returns
  • true if debug is enabled in the underlying logger.

public abstract 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.

Returns
  • true if error is enabled in the underlying logger.

public abstract 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.

Returns
  • true if fatal is enabled in the underlying logger.

public abstract 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.

Returns
  • true if info is enabled in the underlying logger.

public abstract 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.

Returns
  • true if trace is enabled in the underlying logger.

public abstract 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.

Returns
  • true if warn is enabled in the underlying logger.

public abstract void trace (Object message)

Log a message with trace log level.

Parameters
message log this message

public abstract void trace (Object message, Throwable t)

Log an error with trace log level.

Parameters
message log this message
t log this cause

public abstract void warn (Object message, Throwable t)

Log an error with warn log level.

Parameters
message log this message
t log this cause

public abstract void warn (Object message)

Log a message with warn log level.

Parameters
message log this message