geirm 01/02/26 22:06:31
Modified: xdocs developer-guide.xml
Log:
-Added additional and more info about build targets.
- Sprinkled examples of catching the two new o.a.v.e exceptions for
app use (w/o saying anything about them... it's a good start, I supposed)
- Described the overridable methods of VelocityServlet.
Revision Changes Path
1.17 +54 -1 jakarta-velocity/xdocs/developer-guide.xml
Index: developer-guide.xml
===================================================================
RCS file: /home/cvs/jakarta-velocity/xdocs/developer-guide.xml,v
retrieving revision 1.16
retrieving revision 1.17
diff -u -r1.16 -r1.17
--- developer-guide.xml 2001/02/26 06:38:54 1.16
+++ developer-guide.xml 2001/02/27 06:06:30 1.17
@@ -94,7 +94,15 @@
</li>
<li>
<code>docs</code> builds these docs in the <code>docs</code> directory
+ using Velocity's <a href='anakia.html'>Anakia</a> XML transformation tool.
+ Allowing you to use
+ Velocity templates in place of stylesheets
+ - give it a try!
</li>
+ <li>
+ <code>jarsrc</code> bundles all the Velocity source code into a single
+ jar, placed in the <code>bin</code> directory.
+ </li>
<li>
<code>javadocs</code> builds the Javadoc class documentation in the
<code>docs/apidocs</code> directory
@@ -209,6 +217,14 @@
{
template = Runtime.getTemplate("mytemplate.vm");
}
+catch( ResourceNotFoundException rnfe )
+{
+ // couldn't find the template
+}
+catch( ParseErrorException pee )
+{
+ // syntax error : problem parsing the template
+}
catch( Exception e )
{}
@@ -416,7 +432,6 @@
{
public Template handleRequest( Context context )
{
- Template template = null;
String p1 = "Jakarta";
String p2 = "Velocity";
@@ -427,10 +442,20 @@
context.put("list", vec );
+ Template template = null;
+
try
{
template = getTemplate("sample.vm");
}
+ catch( ResourceNotFoundException rnfe )
+ {
+ // couldn't find the template
+ }
+ catch( ParseErrorException pee )
+ {
+ // syntax error : problem parsing the template
+ }
catch( Exception e )
{}
@@ -445,6 +470,34 @@
it's identical to the basic code pattern we mentioned at the beginning of this
guide.
We take the context, add our application data, and return a template.
</p>
+<p>
+For advanced users, the VelocityServlet base class allows you to override parts of
the handling of the request processing. The following methods may be overridden.
+
+<ul>
+ <li> <code>Context createContext(HttpServletRequest request, HttpServletResponse
response )</code>
+ Allows you to create the Context object yourself. This allows more advanced
techniques, such as chaining
+ or pre-loading with tools or data. The default implementation simply returns a
VelocityContext
+ object with the request and response objects placed inside.
+ </li>
+ <li> <code>void setContentType( HttpServletRequest request, HttpServletResponse
response )</code>
+ Allows you to examine the request and set the content type yourself, depending
on the request or
+ client. The default implementation sets the content type to be that either
specified in the
+ velocity.properties, if any, or the default, "text/html" if not specified in
the properties.
+ </li>
+ <li> <code>void mergeTemplate( Template template, Context context,
HttpServletResponse response )</code>
+ Allows you to produce the output stream. The VelocityServlet uses a pool of
very efficient Writer classes,
+ so this would usually be overridden in special situations.
+ </li>
+ <li> <code>void requestCleanup( HttpServletRequest request, HttpServletResponse
response, Context context )</code>
+ Allows you to do any cleanup or resource reclamation at the end of the request
processing. The default
+ does nothing.
+ </li>
+</ul>
+
+For further information, please see the Javadoc <a href='apidocs/index.html'>API
documentation</a>.
+</p>
+
+
<strong>Deployment</strong>
<p>
When you deploy your Velocity-based servlets, you will certainly want to ensure
that your properties file is used to configure
