Pattern Layout

Examples

Here are examples of format modifiers that are used with the c conversion character. The c conversion character reports the name of the logger.

Format Modifier	Left Justification	Minimum Width	Maximum Width	Explanation
%20c	no	20	none	If the data item occupies fewer than 20 characters, pad to the left, using spaces.
%-20c	yes	20	none	If the data item occupies fewer than 20 characters, pad to the right, using spaces.
%.30c	not applicable	none	30	If the data item exceeds 30 characters, left-truncate the data item.
%20.30c	no	20	30	If the data item occupies fewer than 20 characters, pad to the left, using spaces. If the data item exceeds 30 characters, left-truncate the data item.
%-20.30c	yes	20	30	If the data item occupies fewer than 20 characters, pad to the right, using spaces. If the data item exceeds 30 characters, left-truncate the data item.

Example of a Pattern Layout

Here is an excerpt of an XML file that contains a pattern layout:

<layout>
   <param name="ConversionPattern"  value="%d %-5p %t %c (%F:%L) %m"/>  
</layout>

Here is an explanation:

Pattern Layout	Explanation	Example
%d	reports the date of the log event and formats the date using the default format, ISO8601.	2008-06-25 10:24:22,234; Note: The semicolon (;) is literal text.
%-5p	reports the level of the log event and left-justifies the level in output. If the level occupies fewer than five characters, the level is padded on the right.	WARN ; Note: The semicolon (;) is literal text.
%t	reports the identifier of the thread that generated the log event.	3; Note: The semicolon (;) is literal text.
%c{2}	reports the name of the logger that generated the log event. The precision specifier limits the logger name to two subfields, causing left-truncation.	The full logger name is Log4SAS.Appender.IOMCallContext. The formatted output is Appender.IOMCallContext;. Note: The semicolon (;) is literal text.
(%F:%L)	reports the filename and the line number in the application that generated the log event. The parentheses and colon are literal text that was specified in the conversion pattern.	(ynl4sas.c:149); Note: The parentheses ( () ), colon (:), and semicolon (;) are literal text.
%m	reports the message that is supplied by the application and that is associated with the log event.	Numeric maximum was larger than 8, am setting to 8.

Example of a Formatted Log Event

Here is an example of a formatted log event that is delivered to the appropriate output device:

Date	Level	Thread ID	Logger	Filename/Line Number	Message
20008-06-25 10:24:22,234;	WARN;	3;	Appender.IOMCallContext;	(ynl4.sas.c:149);	Numeric maximum was larger than 8, am setting to 8.

Here is another view of the formatted log event as output:

2008-06-25-10:24:22,234; WARN; 3; Appender.IOMCallContext; (yn14.sas.c:149); 
                            Numeric maximum was larger than 8, am setting to 8.

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