caucho
Resin
FAQ
Reference Guide
Demo
Tutorial

JSP page
Config
URLs
Database Forms
XTP Copy
Hello Tag
Vary Filter
HardCore
Mailing Forms
Beans
Cache
XSL Filter
run-at
jndi app config

Servlet
Parse Errors
Runtime Errors
Debugging
 Debugging

Runtime Errors
JSP page
Config

Tracing

For larger projects, tracing is vital. Smaller projects can get away with printing to stderr for debugging or stepping through statements. Larger projects need to have tracing in place before debugging. When debugging, you turn on the tracing. When you deploy the application, you turn off the tracing.

In Resin, logging is just another stream, similar to the familiar print writer. It's enabled by the configuration file. Using the following idiom adds tracing with essentially no performance penalty.

<%@ page import='com.caucho.vfs.*' %>
<%!
static WriteStream dbg = LogStream.open("/foo.com/jsp");
%>

<%
if (dbg.canWrite())
  dbg.log("starting page");
%>

When you run this, nothing will get logged until the configuration file enables '/foo.com/test'. You could also enable '/foo.com' to get all logging from foo.com.

Here's the configuration file for logging to a log file in log/foo.log.

<caucho.com>
  <log id='/foo.com/jsp' href='log/foo.log'/>

  <http-config>
    ...
  </http-config>
</caucho.com>

href can be any VFS path known to Resin. 'stderr:' will log to the standard error.


Runtime Errors
JSP page
Config
Copyright © 1998-2002 Caucho Technology, Inc. All rights reserved.
Resin® is a registered trademark, and HardCoretm and Quercustm are trademarks of Caucho Technology, Inc.