org.apache.poi.util

Class POILogger

java.lang.Object

org.apache.poi.util.POILogger

Direct Known Subclasses:

CommonsLogger, NullLogger, SystemOutLogger

@Internal
public abstract class POILogger
extends java.lang.Object

A logger interface that strives to make it as easy as possible for developers to write log calls, while simultaneously making those calls as cheap as possible by performing lazy evaluation of the log message.

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEBUG
static int	ERROR
static int	FATAL
static int	INFO
protected static java.lang.String[]	LEVEL_STRINGS Long strings for numeric log level.
protected static java.lang.String[]	LEVEL_STRINGS_SHORT Short strings for numeric log level.
static int	WARN

Method Summary

Modifier and Type	Method and Description
protected abstract void	_log(int level, java.lang.Object obj1) Log a message
protected abstract void	_log(int level, java.lang.Object obj1, java.lang.Throwable exception) Log a message
abstract boolean	check(int level) Check if a logger is enabled to log at the specified level This allows code to avoid building strings or evaluating functions in the arguments to log.
abstract void	initialize(java.lang.String cat)
void	log(int level, java.lang.Object... objs) Log a message.

Methods inherited from class java.lang.Object

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

Field Detail

DEBUG

public static final int DEBUG

See Also:

Constant Field Values

INFO

public static final int INFO

See Also:

Constant Field Values

WARN

public static final int WARN

See Also:

Constant Field Values

ERROR

public static final int ERROR

See Also:

Constant Field Values

FATAL

public static final int FATAL

See Also:

Constant Field Values

LEVEL_STRINGS_SHORT

protected static final java.lang.String[] LEVEL_STRINGS_SHORT

Short strings for numeric log level. Use level as array index.

LEVEL_STRINGS

protected static final java.lang.String[] LEVEL_STRINGS

Long strings for numeric log level. Use level as array index.

Method Detail

initialize

public abstract void initialize(java.lang.String cat)

_log

protected abstract void _log(int level,
                             java.lang.Object obj1)

Log a message

Parameters:

level - One of DEBUG, INFO, WARN, ERROR, FATAL

obj1 - The object to log. This is converted to a string.

_log

protected abstract void _log(int level,
                             java.lang.Object obj1,
                             java.lang.Throwable exception)

Log a message

Parameters:

level - One of DEBUG, INFO, WARN, ERROR, FATAL

obj1 - The object to log. This is converted to a string.

exception - An exception to be logged

check

public abstract boolean check(int level)

Check if a logger is enabled to log at the specified level This allows code to avoid building strings or evaluating functions in the arguments to log. An example:

 if (logger.check(POILogger.INFO)) {
     logger.log(POILogger.INFO, "Avoid concatenating " + " strings and evaluating " + functions());
 }
 

Parameters:

level - One of DEBUG, INFO, WARN, ERROR, FATAL

log

public void log(int level,
                java.lang.Object... objs)

Log a message. Lazily appends Object parameters together. If the last parameter is a Throwable it is logged specially.

Parameters:

level - One of DEBUG, INFO, WARN, ERROR, FATAL

objs - the objects to place in the message