PC Professionell 2004 December/PCpro_2004_12.ISO/files/webserver/xampp/xampp-cocoon-addon-1.4.9-installer.exe/faq-debugging.xml

Extensible Markup Language | 2004-07-12 | 5.1 KB | 124 lines

<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE faqs PUBLIC "-//APACHE//DTD FAQ V1.0//EN" "faq-v10.dtd">
<faqs title="Debugging FAQs">

  <faq>
    <question>How do I debug Cocoon using JDK1.3+?</question>
    <answer>
      <p>
        With JDK1.3 or above, first set the <code>CATALINA_OPTS</code> (for
        Tomcat 4.x as shown below (on Win2K).
      </p>
      <source><![CDATA[
set CATALINA_OPTS=-server -Xdebug -Xnoagent -Djava.compiler=NONE
    -Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=8000
]]></source>
      <note>
        For Tomcat 3.x the param is TOMCAT_OPTS and the first value is
        <code>-classic</code> instead of <code>-server</code>.
      </note>
      <p>
        Add it to the <code>catalina.bat</code>, that can be found in
        <code>%TOMCAT_HOME%\bin\</code>, right after the first <code>rem</code>
        section.
        <br/>
        The same information in more detail can be found at
        <link href="http://jakarta.apache.org/site/idedev-rdtomcat.html">Setting
        up Tomcat for Remote Debugging</link>.
      </p>
      <p>
        The problem of this approach is the blocking of using Tomcat in another
        mode. You always have to touch <code>catalina.bat</code> again when
        changing the mode and this file is really a batch beast, isn't it?
        Furthermore <code>catalina.bat</code> is only a starting mode library
        and should not be touched by hand IMO.<br/>
        Let me propose my approach: Go to the last line of
        <code>startup.bat</code> where <code>catalina.bat</code> is called.
        Replace
      </p>
      <source>call "%EXECUTABLE%" start %CMD_LINE_ARGS%</source>
      <p>with</p>
      <source>
set JPDA_TRANSPORT=dt_socket
set JPDA_ADDRESS=8000
call "%EXECUTABLE%" jpda start %CMD_LINE_ARGS%
      </source>
      <p>
        A switch can now be done by adding and removing <code>jpda</code>. You
        can also place the old line in comments and switch between them. Or you
        copy <code>startup.bat</code> to <code>debug.bat</code> and do the
        changes there.
      </p>
      <note>
        Note that Tomcat must be started using <code>startup.bat</code> in order
        to set these values; if you are using
        "<code>java.exe -jar ...bootstrap.jar start</code>" or anything similar to
        start Tomcat, you have to set the <code>CATALINA_OPTS</code> on the
        commandline or for Windows in general.
      </note>
      <note>
        If you use Jetty included with Cocoon 2.1 it's much easier. Instead of
        doing "<code>cocoon.bat servlet</code>" you simply call
        "<code>cocoon.bat servlet-debug</code>".
      </note>
      <p>
        After having started Tomcat or the servlet container of your choice in
        remote debugging mode, attach the debugger to localhost:8000 using
        "<code>jdb -attach myhost:8000</code>". If you get an error
        "<code>Error accessing shared memory, rc = -1</code>", try
        "<code>jdb -connect com.sun.jdi.SocketAttach:port=8000</code>" instead.
        <br/>
        More information on this can be found in the
        <link href="http://java.sun.com/j2se/1.4.2/docs/guide/jpda/conninv.html">
        JPDA documentation</link>.
      </p>
      <note>
        The attaching of the debugger to that port can be done very easily in
        almost all modern IDEs as Eclipse, IDEA, NetBeans or JBuilder. Mostly
        port <code>8000</code> and <code>dt_socket</code> are preselected.
      </note>
    </answer>
  </faq>
  <faq>
    <question>
      Now that I have prepared Tomcat and my IDE for debugging: How do I debug?
    </question>
    <answer>
      <p>
        Of course we can not give to many details here as it might be different
        for all the possible IDEs out there, but the general proceeding should
        be the same. The following steps are for jdb, it should be much easier
        for the IDEs.<br/>
        1. Set a breakpoint in a class via
           "<code>stop in org.apache.cocoon.components.pipeline.AbstractProcessingPipeline.checkPipeline</code>".
        <br/>
        2. Enter a URL in your browser to get Cocoon to do the stuff that needs
           debugging. When your breakpoint is hit, you'll get the message in jdb:
           <br/>
           <code>Breakpoint hit: "thread=Thread-11",
           org.apache.cocoon.components.pipeline.AbstractProcessingPipeline.checkPipeline(),
           line=363 bci=0</code>.
        <br/>
        3. Use the debugger commands "print", "next", and "cont" to examine the
           data and step through the code.
      </p>
    </answer>
  </faq>
</faqs>