com.databasesandlife.util

Class PerThreadLog4jAppender

java.lang.Object

org.apache.log4j.AppenderSkeleton

com.databasesandlife.util.PerThreadLog4jAppender

All Implemented Interfaces:

org.apache.log4j.Appender, org.apache.log4j.spi.OptionHandler

public class PerThreadLog4jAppender
extends org.apache.log4j.AppenderSkeleton

Allows each thread to log to its own logger.

Usage:

    final String threadName = ...;
    Layout layout = new PatternLayout("%d{yyyy-MM-dd HH:mm:ss} %p: %m%n");
    FileAppender toFile = new FileAppender(layout, "C:/" + threadName);
    Runnable runnable = new Runnable() {
        public void run() {
            NDC.push(threadName);
            try {
                Logger.getLogger(getClass()).info("Some text!");
            }
            finally { NDC.remove(); }
        }
    };
    Thread thread = new Thread(runnable, threadName); 
    PerThreadLog4jAppender
        .getSharedInstanceAndAddToLog4jIfNecessary()
        .addThreadAppender(thread, toFile);
 

There is no need to remove appenders from this object once threads exit.

Author:

This source is copyright Adrian Smith and licensed under the LGPL 3.

See Also:

Project on GitHub

Field Summary

Fields

Modifier and Type	Field and Description
protected Map<Thread,org.apache.log4j.AppenderSkeleton>	appenderForThread
protected static PerThreadLog4jAppender	sharedInstance

Fields inherited from class org.apache.log4j.AppenderSkeleton

closed, errorHandler, headFilter, layout, name, tailFilter, threshold

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	PerThreadLog4jAppender()

Method Summary

Modifier and Type	Method and Description
void	addThreadAppender(Thread t, org.apache.log4j.AppenderSkeleton a)
protected void	append(org.apache.log4j.spi.LoggingEvent event)
void	close()
static PerThreadLog4jAppender	getSharedInstanceAndAddToLog4jIfNecessary()
void	registerSubThread(Thread mainThread, Thread subThread) Makes logs from subThread go to the same appender as the calling thread
boolean	requiresLayout()

Methods inherited from class org.apache.log4j.AppenderSkeleton

activateOptions, addFilter, clearFilters, doAppend, finalize, getErrorHandler, getFilter, getFirstFilter, getLayout, getName, getThreshold, isAsSevereAsThreshold, setErrorHandler, setLayout, setName, setThreshold

Methods inherited from class java.lang.Object

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

Field Detail

sharedInstance

protected static PerThreadLog4jAppender sharedInstance

appenderForThread

protected Map<Thread,org.apache.log4j.AppenderSkeleton> appenderForThread

Constructor Detail

PerThreadLog4jAppender

protected PerThreadLog4jAppender()

Method Detail

getSharedInstanceAndAddToLog4jIfNecessary

public static PerThreadLog4jAppender getSharedInstanceAndAddToLog4jIfNecessary()

addThreadAppender

public void addThreadAppender(Thread t,
                              org.apache.log4j.AppenderSkeleton a)

registerSubThread

public void registerSubThread(Thread mainThread,
                              Thread subThread)

Makes logs from subThread go to the same appender as the calling thread

close

public void close()

requiresLayout

public boolean requiresLayout()

append

protected void append(org.apache.log4j.spi.LoggingEvent event)

Specified by:

append in class org.apache.log4j.AppenderSkeleton