Xtext Project Plan/Features/Logging

User Information

How do I use Logging in Xtext?

• Add org.eclipse.xtext.log4j to the manifest of your bundle:

  org.eclipse.xtext.log4j;bundle-version="1.2.15"

• Register your bundle as a buddy to org.eclipse.xtext.log4j

  Eclipse-RegisterBuddy: org.eclipse.xtext.log4j

• Add your bundle to the loggermap (located in org.eclipse.xtext.logging/plugin.xml):

  <mapentry
     bundleId="org.eclipse.xtext"
     loggername="org\.eclipse\.xtext\..*">
   </mapentry>

• After those preparatory steps, you can now call the logger API:

  log.debug("Starting Xtext UI bundle.");

Developer Information

Required Features

• completely transparent logging
• use same logger API in frontend and backend / IDE vs standalone mode
• levels WARN, ERROR and FATAL will be logged to the Eclipse Error Log

Researched options

The followng options were researched:

• Commons Logging (not feasible due to the fact only ONE configuration can be used throughout the ENTIRE application)
• Log4J bundle from the Eclipse Orbit (still, only one bundle can configure the Log system)

Solution

• Use Log4j, but create a custom Log4j bundle (org.eclipse.xtext.log4j)
• org.eclipse.xtext.logging contains EclipseLogAppender
• Mapping from logger name to Eclipse bundle is achieved by extending the extension point org.eclipse.xtext.logging.loggermap (loggername contains a regex) :

 <extension
       point="org.eclipse.xtext.logging.loggermap">
    <mapentry
          bundleId="org.eclipse.xtext"
          loggername="org\.eclipse\.xtext\..*">
    </mapentry>
    <mapentry
           bundleId="org.eclipse.xtext.reference.ui"
          loggername="org\.eclipse\.xtext\.reference\.ui\..*">
    </mapentry>
     <mapentry
           bundleId="org.eclipse.xtext.ui"
           loggername="org\.eclipse\.xtext\.ui\..*">
     </mapentry>
 </extension>