Can format modifiers be used for two combined conversion characters?

Question

I know how to print the class name and method name with log4j, both fields can be aligned and padded separately, for example. this template:

[%d{ISO8601}] %-5p %-10C{1}:%-10M %m%n 

creates something like:

 [2012-09-20 08:25:12,111] WARN Class :method Logtext1 which should align [2012-09-20 08:25:12,111] WARN ClassTwo :methodName Logtext2 which should align 

This will align the registered text (in most cases), but the class name and method name will be ugly.

So I would like to output something like:

 [2012-09-20 08:25:12,111] WARN Class:method Logtext1 which should align [2012-09-20 08:25:12,111] WARN ClassTwo:methodName Logtext2 which should align 

Can only configuration be used?

Can you suggest another way to output the method name and class name while keeping the log text aligned?

Answer 1

This seems to be impossible using only configuration. The following simpler solution is similar to a custom PatternLayout, which can then be used in log4j.ini with the character "b":

log4j.appender.filelog.layout = your.full.namespace.BPatternLayout log4j.appender.filelog.layout.ConversionPattern = [% d {ISO8601}]% -5p% -30b% m% n

Hope this helps someone else too.

BPatternLayout.java:

 import org.apache.log4j.PatternLayout; import org.apache.log4j.helpers.PatternParser; public class BPatternLayout extends PatternLayout { @Override protected PatternParser createPatternParser(String pattern) { return new BPatternParser(pattern); } } 

BPatternParser.java:

 import org.apache.log4j.helpers.FormattingInfo; import org.apache.log4j.helpers.PatternConverter; import org.apache.log4j.helpers.PatternParser; import org.apache.log4j.spi.LocationInfo; import org.apache.log4j.spi.LoggingEvent; public class BPatternParser extends PatternParser { public BPatternParser(String pattern) { super(pattern); } @Override protected void finalizeConverter(char c) { switch (c) { case 'b': currentLiteral.setLength(0); addConverter(new BPatternConverter(formattingInfo)); break; default: super.finalizeConverter(c); } } private class BPatternConverter extends PatternConverter { BPatternConverter(FormattingInfo formattingInfo) { super(formattingInfo); } @Override protected String convert(LoggingEvent evt) { LocationInfo locationInfo = evt.getLocationInformation(); return getPartialClassName(locationInfo, 1) + ":" + locationInfo.getMethodName(); } /** * Code from org.apache.log4j.helpers.PatternParser.NamedPatternConverter */ private String getPartialClassName(LocationInfo loc, int precision) { String n = loc.getClassName(); if (precision <= 0) { return n; } int len = n.length(); // We substract 1 from 'len' when assigning to 'end' to avoid out of // bounds exception in return r.substring(end+1, len). This can happen if // precision is 1 and the category name ends with a dot. int end = len - 1; for (int i = precision; i > 0; i--) { end = n.lastIndexOf('.', end - 1); if (end == -1) return n; } return n.substring(end + 1, len); } } }