log4javascript 1.4 Lite manual

Contents

• Introduction
• log4javascript static properties/methods
• Levels
• Loggers
• Helping/disabling log4javascript Lite

Introduction

log4javascript Lite is designed to be a basic, lightweight, cross-browser logging tool. It provides functions to log messages of different severity to a pop-up window using the exactly the same syntax as log4javascript. It is designed for situations when the key requirement is just to display logging messages without needing all the features of the standard version of log4javascript.

Below is the complete list of functions and properties available in log4javascript Lite. They make up a small subset of those provided by the standard version of log4javascript. Each function is named and called identically to the equivalent function in log4javascript. Please refer to the log4javascript manual for a detailed explanation of all the concepts alluded to in this document.

log4javascript static properties/methods

Properties

• version The version number of your copy of log4javascript.
• edition The edition of your copy of log4javascript (“log4javascript_lite” in this case”).

Methods

• getDefaultLogger Logger getDefaultLogger() Returns the default and only logger (apart from the null logger). The default logger logs to a simple pop-up window.
• getNullLogger Logger getNullLogger() Returns an empty logger. Useful for disabling all logging.
• setEnabled void setEnabled(Boolean enabled) Parameters:
  • enabled
  Enables or disables all logging, depending on enabled.
• isEnabled Boolean isEnabled() Returns true or false depending on whether logging is enabled.
• setShowStackTraces void setShowStackTraces(Boolean show) Parameters:
  • show
  Enables or disables displaying of error stack traces, depending on show. By default, stack traces are not displayed. (Only works in Firefox)

Levels

Levels are available as static properties of the log4javascript.Level object. In ascending order of severity:

1. log4javascript.Level.ALL
2. log4javascript.Level.TRACE
3. log4javascript.Level.DEBUG
4. log4javascript.Level.INFO
5. log4javascript.Level.WARN
6. log4javascript.Level.ERROR
7. log4javascript.Level.FATAL
8. log4javascript.Level.NONE

Loggers

There are only two loggers in log4javascript Lite: the default logger obtained by calling log4javascript.getDefaultLogger() and the empty logger returned by log4javascript.getNullLogger().

Logger methods

• setLevel void setLevel(Level level) Parameters:
  • level
  Sets the level. Log messages of a lower level than level will not be logged. Default value is ALL (unlike in log4javascript, where the default level is DEBUG).
• getLevel Level getLevel() Returns the level for this logger.
• trace void trace(Object message1[, Object message2, ... ][, Error exception]) Parameters:
  • message1[, message2...]
  • exception [optional]
  Logs one or more messages and optionally an error at level TRACE.
• debug void debug(Object message1[, Object message2, ... ][, Error exception]) Parameters:
  • message1[, message2...]
  • exception [optional]
  Logs one or more messages and optionally an error at level DEBUG.
• info void info(Object message1[, Object message2, ... ][, Error exception]) Parameters:
  • message1[, message2...]
  • exception [optional]
  Logs one or more messages and optionally an error at level INFO.
• warn void warn(Object message1[, Object message2, ... ][, Error exception]) Parameters:
  • message1[, message2...]
  • exception [optional]
  Logs one or more messages and optionally an error at level WARN.
• error void error(Object message1[, Object message2, ... ][, Error exception]) Parameters:
  • message1[, message2...]
  • exception [optional]
  Logs one or more messages and optionally an error at level ERROR.
• fatal void fatal(Object message1[, Object message2, ... ][, Error exception]) Parameters:
  • message1[, message2...]
  • exception [optional]
  Logs one or more messages and optionally an error at level FATAL.
• isEnabledFor Boolean isEnabledFor(Level level, Error exception) Parameters:
  • level
  Returns whether the logger is enabled for the specified level.
• isTraceEnabled Boolean isTraceEnabled() Returns whether the logger is enabled for TRACE messages.
• isDebugEnabled Boolean isDebugEnabled() Returns whether the logger is enabled for DEBUG messages.
• isInfoEnabled Boolean isInfoEnabled() Returns whether the logger is enabled for INFO messages.
• isWarnEnabled Boolean isWarnEnabled() Returns whether the logger is enabled for WARN messages.
• isErrorEnabled Boolean isErrorEnabled() Returns whether the logger is enabled for ERROR messages.
• isFatalEnabled Boolean isFatalEnabled() Returns whether the logger is enabled for FATAL messages.

Enabling / disabling log4javascript Lite

All logging can be enabled or disabled in log4javascript Lite in a number of ways:

• At any time, you can call log4javascript.setEnabled(enabled). This will enable or disable all logging, depending on whether enabled is set to true or false.
• Assign your logger object a value of log4javascript.getNullLogger().
• Replace your copy of log4javascript_lite.js with stubs/log4javascript_lite.js, provided in the distribution. This file has a stub version of each of the functions and methods in the log4javascript Lite API and can simply be dropped in in place of the main file.