Package org.apache.poi.util
Class POILogger
- java.lang.Object
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- org.apache.poi.util.POILogger
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- 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.
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Field Summary
Fields Modifier and Type Field 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
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description protected abstract void
_log(int level, java.lang.Object obj1)
Log a messageprotected abstract void
_log(int level, java.lang.Object obj1, java.lang.Throwable exception)
Log a messageabstract 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.
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Field Detail
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DEBUG
public static final int DEBUG
- See Also:
- Constant Field Values
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INFO
public static final int INFO
- See Also:
- Constant Field Values
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WARN
public static final int WARN
- See Also:
- Constant Field Values
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ERROR
public static final int ERROR
- See Also:
- Constant Field Values
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FATAL
public static final int FATAL
- See Also:
- Constant Field Values
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LEVEL_STRINGS_SHORT
protected static final java.lang.String[] LEVEL_STRINGS_SHORT
Short strings for numeric log level. Use level as array index.
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LEVEL_STRINGS
protected static final java.lang.String[] LEVEL_STRINGS
Long strings for numeric log level. Use level as array index.
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Method Detail
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initialize
public abstract void initialize(java.lang.String cat)
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_log
protected abstract void _log(int level, java.lang.Object obj1)
Log a message- Parameters:
level
- One of DEBUG, INFO, WARN, ERROR, FATALobj1
- The object to log. This is converted to a string.
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_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, FATALobj1
- The object to log. This is converted to a string.exception
- An exception to be logged
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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
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log
public void log(int level, java.lang.Object... objs)
Log a message. Lazily appends Object parameters together. If the last parameter is aThrowable
it is logged specially.- Parameters:
level
- One of DEBUG, INFO, WARN, ERROR, FATALobjs
- the objects to place in the message
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