Log4j: Truncate from the END, conversion patterns

[Bunty Kumar]

I want to truncate priority of the logging event(DEBUG, INFO, WARN, ERROR, FATAL) from the end(not from the beginning).
I am using conversion patterns like
Sev_%.10p Application= "MyApp" Text= %m%n
But it truncate from BEGINNING & it give me last character(G, O, N, R, L). I want only first character(D, I, W, E, F)
Thanks v much,
Rakesh

[miguel martin]

%.-30logger NA none 30 Truncate from the end if the logger name is longer than 30 characters


dew

[Tanzy Akhtar]

Welcome to javaranch Bunty and Miguel..

[Greg Bishop]

You have to extend pattern layout, override the createPatternParser, and create a PatternParser and a PatternConverter. Here is one I have that prints the first letter as you asked, and also prints the first 3 letters of each package level making them smaller as well.

log4j.appender.O.layout=net.whatever.services.sys.logger.MyLayout
log4j.appender.O.layout.ConversionPattern=%Z[%d{dd HH:mm:ss}] %Y:%L %m%n

package net.whatever.services.sys.logger.MyLayout;

import org.apache.log4j.Level;
import org.apache.log4j.PatternLayout;
import org.apache.log4j.spi.LoggingEvent;
import org.apache.log4j.helpers.FormattingInfo;
import org.apache.log4j.helpers.PatternConverter;
import org.apache.log4j.helpers.PatternParser;

SomeClass extends PatternLayout {

   ...

    @Override
    protected PatternParser createPatternParser(String pattern) {
        return new SpecialPatternParser(((pattern==null) ? PatternLayout.DEFAULT_CONVERSION_PATTERN:pattern));
    }

    class SpecialPatternParser extends PatternParser {
     
        /**
         * @param pattern
         */
        public SpecialPatternParser(String pattern) {
            super(pattern);
             
        }
     
        @Override
        protected void finalizeConverter(char arg0) {
             
            PatternConverter pc = null;
            switch(arg0)
            {
            case 'Z':
                pc = new SpecialPatternConverter(formattingInfo, 0);
                break;
            case 'Y':
                pc = new SpecialPatternConverter(formattingInfo, 1);
                break;
            default:
                super.finalizeConverter(arg0);
            }
            if(pc!=null) addConverter(pc);
        }
        
    }
    
    class SpecialPatternConverter extends PatternConverter {
        
        int type = 0;
    
        public SpecialPatternConverter(FormattingInfo fi, int type) {
            super(fi);
            this.type = type;
        }

        public String convert(LoggingEvent event) {
            String str = null;
            switch(type){
            case 0:
                str = event.getLevel().toString().substring(0,1);
                break;
            case 1:
                str = event.getLocationInformation().getClassName();
                StringBuffer sb = new StringBuffer(str.length());
                while(str.indexOf('.')!=-1){
                   String part = str.substring(0, str.indexOf('.'));
                   sb.append( part.length() > 3 ? part.substring(0,3) + "~" : part + "." );
                   str = str.substring(str.indexOf('.')+1);
                }
                str = sb.append(str).toString();
                break;
            }
            return str;
            
       }

    }