Difference between revisions of "FAQ How do I use the platform logging facility?"

Revision as of 22:47, 1 June 2006

The Eclipse runtime plug-in provides a simple set of APIs for logging exceptions, warnings, or other information useful in debugging or servicing a deployed Eclipse product. The intent of the log is to record information that can be used later to diagnose problems in the field. Because this information is not directed at users, you do not need to worry about translating messages or simplifying explanations into a form that users will understand. The idea is that when things go wrong in the field, your users can send you the log file to help you figure out what happened.

Each plug-in has its own log associated with it, but all logged information eventually makes its way into the platform log file (see the getLogFileLocation method on Platform). The log for a plug-in is accessed from the plug-in’s class, using getLog inherited from Plugin. You can attach a listener to an individual log or to the platform log if you are interested in receiving notification of logged events. Use addLogListener on either Platform or the result of Plugin.getLog().

You can write any kind of IStatus object to the log file, including a MultiStatus if you have hierarchies of information to display. If you create your own subclass of the utility class Status, you can override the getMessage method to return extra information to be displayed in the log file. Many plug-ins add convenience methods to their plug-in class for writing messages and errors to the log:

   import org.eclipse.core.runtime.Status;
   ...
   public void log(String msg) {
      log(msg, null);
   }
   public void log(String msg, Exception e) {
      getLog().log(new Status(Status.INFO, myPluginID, 
                                         Status.OK, msg, e));
   }

During development, you can browse and manipulate the platform log file using the PDE Error Log view (Window > Show View > Other > PDE Runtime > Error Log). You can also have the log file mirrored in the Java console by starting Eclipse with the -consoleLog command-line argument.

   eclipse -vm c:\jre\bin\java.exe -consoleLog

We explicitly pass the VM because on Windows you have to use java.exe instead of javaw.exe if you want the Java console window to appear.

See Also:

• FAQ Where can I find that elusive .log file?