On Thu, 9 Jan 2003, Martin Jacobson wrote:
> Date: Thu, 09 Jan 2003 16:06:27 +0100 > From: Martin Jacobson <[EMAIL PROTECTED]> > Reply-To: Tomcat Users List <[EMAIL PROTECTED]> > To: Tomcat Users List <[EMAIL PROTECTED]> > Subject: Re: DTD for server.xml?? > > Craig R. McClanahan wrote: > > > > On Wed, 8 Jan 2003, Turner, John wrote: > > > > > >>Date: Wed, 8 Jan 2003 11:31:16 -0500 > >>From: "Turner, John" <[EMAIL PROTECTED]> > >>Reply-To: Tomcat Users List <[EMAIL PROTECTED]> > >>To: "'[EMAIL PROTECTED]'" <[EMAIL PROTECTED]> > >>Subject: DTD for server.xml?? > >> > >> > >>Hello - > >> > >>I notice that the top of web.xml has: > >> > >><?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";> > >> > >>yet the top of server.xml has nothing. > >> > >>I'm very new to XML, so forgive me if this is a lame or FA question, but is > >>there a DTD for server.xml? If so, why isn't it specified in server.xml, > >>and what is the URL? Is server.xml "real, official XML" or just > >>"convenience" XML? > >> > > > > > > There is no DTD for server.xml because there cannot be. > > > > The problem is that server.xml is extensible -- for example, the set of > > attributes recognized by a <Valve> or <Context> element depends on the > > implementation class of the internal component that corresponds to it. > > The startup process uses Java reflection to match them up to property > > setters on the corresponding beans. There is no way to express this kind > > of thing in a DTD. > > > > Your server.xml is (and must be) "well formed" XML. It just cannot be > > validated. > > > > There may be other good reasons, but this isn't one of them :-) > Here is an extract from my server.xml... > <Logger className="org.apache.catalina.logger.FileLogger" > prefix="catalina_log." suffix=".txt" > timestamp="true" > /> > > This could be equally well expressed as > <Logger className="org.apache.catalina.logger.FileLogger"> > <property> > <property-name>prefix</property-name> > <property-value>catalina_log.</property-value> > </property> > <property> > <property-name>suffix</property-name> > <property-value>.txt</property-value> > </property> > <property> > <property-name>timestamp</property-name> > <property-value>true</property-value> > </property> > </Logger> > > or, more concisely as > > <Logger className="org.apache.catalina.logger.FileLogger"> > <property name="prefix" value="catalina_log."/> > <property name="suffix" value=".txt"/> > <property name="timestamp" value="true"/> > </Logger> > > In both cases, the abstraction of property names allows a DTD to be > defined that is inherently extensible, and thus would allow an XML > parser to validate server.xml even if extended by an admin. > > Or am I missing something? > Well, most people edit server.xml by hand, and even your more "concise" version is a lot of extra typing :-). It also doesn't cover the case where a <Listener> element that you might have dynamically creates some new digester rules (commons-digester is what Tomcat uses to read server.xml and web.xml files) to recognize additional elements on the fly. The right answer to editing server.xml files is to not do it -- let a tool do it for you. That way, the syntax is irrelevant to the user. > Martin Craig -- To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> For additional commands, e-mail: <mailto:[EMAIL PROTECTED]>
