JSP precompilation and including "webinc.xml" in web.xml

[Al Tingley <at...@iperia.com>]

Hello,
We are trying to automate the pre-compilation of our JSP files with JspC and
the inclusion of the generated "webinc.xml" file in our application
"web.xml" file.  We have constructed an application web.xml as shown below.
Both "web.xml" and "webinc.xml" are local to the
.../webapps/<application>/WEB-INF/ directory.

Our problem is that Tomcat complains when starting up with the message:
	 org.xml.sax.SAXParseException: Relative URI "webinc.xml"; can not
be resolved without a base URI.

Note the local reference to "webinc.xml" below in the DOCTYPE tag.

If we change the reference to "webinc.xml" to an absolute URI of the form
below (on Windows):

	file://E/jakarta-tomcat-4.0.4b3/webapps/appname/WEB-INF/webinc.xml

... we get a null pointer exception when Tomcat starts up (parser error at
the line where we reference the file to be included):

2002-06-04 08:55:27 ContextConfig[/voicemail] Parse error in application
web.xml
java.lang.NullPointerException
	at org.apache.crimson.parser.Parser2.parseInternal(Parser2.java:524)
	at org.apache.crimson.parser.Parser2.parse(Parser2.java:305)
	at
org.apache.crimson.parser.XMLReaderImpl.parse(XMLReaderImpl.java:442)
	at
org.xml.sax.helpers.XMLReaderAdapter.parse(XMLReaderAdapter.java:223)
	at javax.xml.parsers.SAXParser.parse(SAXParser.java:314)
	...

What are we doing wrong?  We're using Tomcat 4.0.4b3.
Thanks,
Alan Tingley
Iperia, Inc.

---
The application web.xml file:

<?xml version="1.0" encoding="ISO-8859-1"?>

<!DOCTYPE web-app
    PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
    "http://java.sun.com/dtd/web-app_2_3.dtd"
    [<!ENTITY includes SYSTEM "webinc.xml">]
>

<web-app>
    <!-- all of the precompiled jsp declarations and mappings are in this
included file from the JspC -->
    &includes;
</web-app>

---
Output when starting up Tomcat:

Starting service Tomcat-Standalone
Apache Tomcat/4.0.4-b3
PARSE error at line 6 column -1
org.xml.sax.SAXParseException: Relative URI "webinc.xml"; can not be
resolved without a base URI.


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Re: JSP precompilation and including "webinc.xml" in web.xml

["David M. Karr" <dm...@earthlink.net>]

>>>>> "Al" == Al Tingley <at...@iperia.com> writes:

    Al> Hello,
    Al> We are trying to automate the pre-compilation of our JSP files with JspC and
    Al> the inclusion of the generated "webinc.xml" file in our application
    Al> "web.xml" file.  We have constructed an application web.xml as shown below.
    Al> Both "web.xml" and "webinc.xml" are local to the
    Al> .../webapps/<application>/WEB-INF/ directory.

    Al> Our problem is that Tomcat complains when starting up with the message:
    Al> 	 org.xml.sax.SAXParseException: Relative URI "webinc.xml"; can not
    Al> be resolved without a base URI.

    Al> Note the local reference to "webinc.xml" below in the DOCTYPE tag.

I got the complete precompilation process to work, but I gave up on trying to
reference the include file with an entity reference.  It just doesn't work.

What I was able to do was write an XSLT stylesheet that takes the main
"web.xml" and the generated include file and generates a new "web.xml" that
incorporates both files.  It uses the Ant "style" task to do the
transformation.

A slight wrinkle is that the generated include file is not a fully
"well-formed" XML file, in that it doesn't have a "root" element.  So, in order
for the XML parser (used by Ant) to grok it, I had to write a simple
well-formed wrapper that references the include file with an entity reference.
It's ironic that I'm using the same mechanism in this process that I gave up
with using inside of Tomcat.

I'll show all the pieces of my solution here.

This is the excerpt from my "build-war" Ant target related to this:

-------------------------
  <delete dir="jspc"/>
  <mkdir dir="jspc"/>
  <java classname="org.apache.jasper.JspC" fork="yes">
   <arg line="-v -d jspc -p org.apache.jsp
              -uriroot build
              -webinc web-inf/webinc.xml -webapp build "/>
   <classpath>
    <pathelement location="${catalina.home}/common/lib/jasper-compiler.jar"/>
    <pathelement location="${catalina.home}/common/lib/jasper-runtime.jar"/>
    <pathelement location="weblib/servlet.jar"/>
   </classpath>
  </java>
  <!-- Here, run a "style" task to merge the two "web.xml" pieces. -->
  <style basedir="build/WEB-INF"
         in="web-inf/web.xml" out="build/WEB-INF/web2.xml"
         style="web-inf/webmerge.xsl">
   <param name="includeFile" expression="includeWrapper.xml"/>
  </style>
  <move file="build/WEB-INF/web2.xml" tofile="build/WEB-INF/web.xml"/>
  <javac srcdir="jspc" destdir="classes" debug="on" optimize="off"
         deprecation="on">
   <classpath>
    <pathelement location="${catalina.home}/common/lib/jasper-compiler.jar"/>
    <pathelement location="${catalina.home}/common/lib/jasper-runtime.jar"/>
    <fileset dir="weblib">
     <include name="*.jar"/>
    </fileset>
   </classpath>
   <include name="**/*.java"/>
  </javac>
  <copy todir="build/WEB-INF/classes">
   <fileset dir="webprops">
    <include name="**/*.properties"/>
   </fileset>
   <fileset dir="classes">
    <include name="com/intsoft/strutstest/**/*.class"/>
    <include name="org/apache/jsp/**/*.class"/>
   </fileset>
  </copy>
  <jar jarfile="deploy/strutstest.war">
   <fileset dir="build">
    <include name="**"/>
    <exclude name="*.jsp"/>
   </fileset>
  </jar>
-------------------------

Following this is the "includeWrapper.xml" file, which references the generated
include file.  Note that I have to reference a path of "web-inf/webinc.xml",
which is the path to the generated file in my build tree (not my deploy tree).
I'm using Ant 1.4.  In Ant 1.5.1, there is apparently some new features in the
"style" task that allow the specification of an alternate EntityResolver that
would allow me to avoid hardcoding the name of the directory the file is in.

-------------------------
<?xml version="1.0"?>
<!DOCTYPE web-app
  PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
  "http://java.sun.com/dtd/web-app_2_3.dtd"
[
<!ENTITY webinc PUBLIC "webinc" "file:web-inf/webinc.xml">
]
>
<web-app>
 &webinc;
</web-app>
-------------------------

And finally, here is the stylesheet (webmerge.xsl) that does the
transformation:

-------------------------
<?xml version="1.0"?>
<xsl:stylesheet
 version="1.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

 <!-- This takes a parameter indicating the name of the secondary file
      to merge in.  When we've matched the "web-app" element, we will first
      insert the "servlet" elements of the include file, then the "servlet"
      elements of the main file, then the "servlet-mapping" elements of the
      include file, then the "servlet-mapping" elements of the main file, and
      then all the remaining elements of the main file (which will be
      specified explicitly by element type.
 -->

 <xsl:output method="xml" indent="yes"
        doctype-public="-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
        doctype-system="http://java.sun.com/dtd/web-app_2_3.dtd"/>

 <xsl:param name="includeFile"/>

 <!-- get the required elements of "web-app", in their defined order,
      according to the DTD. -->
 <xsl:template match="/web-app">
   <web-app>
     <xsl:apply-templates select="icon"/>
     <xsl:apply-templates select="display-name"/>
     <xsl:apply-templates select="description"/>
     <xsl:apply-templates select="distributable"/>
     <xsl:apply-templates select="context-param"/>
     <xsl:apply-templates select="filter"/>
     <xsl:apply-templates select="filter-mapping"/>
     <xsl:apply-templates select="listener"/>
     <xsl:apply-templates select="servlet"/>
     <xsl:copy-of select="document($includeFile)/web-app/servlet"/>
     <xsl:apply-templates select="servlet-mapping"/>
     <xsl:copy-of select="document($includeFile)/web-app/servlet-mapping"/>
     <xsl:apply-templates select="session-config"/>
     <xsl:apply-templates select="mime-mapping"/>
     <xsl:apply-templates select="welcome-file-list"/>
     <xsl:apply-templates select="error-page"/>
     <xsl:apply-templates select="taglib"/>
     <xsl:apply-templates select="resource-env-ref"/>
     <xsl:apply-templates select="resource-ref"/>
     <xsl:apply-templates select="security-constraint"/>
     <xsl:apply-templates select="login-config"/>
     <xsl:apply-templates select="security-role"/>
     <xsl:apply-templates select="env-entry"/>
     <xsl:apply-templates select="ejb-ref"/>
     <xsl:apply-templates select="ejb-local-ref"/>
   </web-app>
 </xsl:template>

 <xsl:template match="*">
   <xsl:for-each select="@*">
     <xsl:attribute name="{.}">
       <xsl:value-of select="."/>
     </xsl:attribute>
   </xsl:for-each>
   <xsl:copy-of select="."/>
 </xsl:template>

</xsl:stylesheet>
-------------------------

-- 
===================================================================
David M. Karr          ; Java/J2EE/XML/Unix/C++
dmkarr@earthlink.net


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