Message and trace logging
Portlets write message and trace information to log files in...
PortalServer_root/logs
The PortletContext object in the standard portlet API includes a log() method.
For example...
public void processAction(ActionRequest request, ActionResponse response) throws PortletException, IOException { PortletContext context = getPortletContext(); try { String save = request.getParameter("save"); if (save != null) { PortletPreferences prefs = request.getPreferences(); prefs.setValue("userName",request.getParameter("username")); prefs.store(); } } catch ( IOException ioe ) { context.log("An IO error occurred when trying to save the name."); } catch ( PortletException pe ) { context.log("A portlet exception was thrown when trying to save the name."); } }The IBM Portlet API provides the PortletLog class, which has methods to write specific types of message and trace information to the logs.
debug() trace information info() informational messages error() error messages warn() warning messages
If an IBM portlet needs to access the portlet log multiple times in a method, it is good idea to assign the log reference to a variable, for example:
private PortletLog myLogRef = getPortletLog();Since logging operations are expensive, the PortletLog class of the IBM Portlet API provides methods to determine if logging is enabled for a given level. The portlet should write to the log of a given level only if the log is tracking messages of that level.For example:
if( getPortletLog().isDebugEnabled() ) { myLogRef.debug("Warning, Portlet Resources are low!"); }
Enable logging for portlets
Portlet logging is enabled by setting the following trace strings in the log.properties file.
- Standard portlets
- javax.portlet.Portlet=all
The Java Portlet Specification defines that log statements from the JSR portlets are also passed on to the ServletContext.log() method, which will additionally write them to System.out in the default configuration.
- IBM portlets
- org.apache.jetspeed.portlet.PortletLog=all
See WebSphere Portal run-time logs for a description of how trace strings are set in the log.properties file.
Related information
Parent topic:
Understand the basics