Two patches below:
1. ResourceManager to return a null template if the file was not
found (this is what the comment some lines above states it
would do; I tested that this is the correct behaviour -
otherwise it would emit wrong error doing template.parse() ).
2. VelocityServlet to provide a hook for subclasses to be able to
setup (a layered) context.
I also believe that VelocityServlet should not be abstract any
more to allow something like the JSP examples which operate
directly on the request and response objects.
These patches are fully backward compatible.
Next things I'm going to do:
A. Fix the log messages to reflect the correct template name
for errors within #parsed files. Also fix the parse depth
bug.
I will use a stack for the template names in the
LocalContextAdapter.
B. Fix FileResouceLoader and Logfile to allow files relative
to the servlet WEBAPP (when the properties entries do not
start with a /). If no servlet context has been setup,
then it will continue using the current pwd.
C. Submit an ApplicationServlet and context tools that
allows creating an MVC servlet based on VTL. This is already
working greatly for me (I moved my whole application from
Trubine to Velocity! - since Turbine dev is yet to dynamic
and, AFAICS, Vel is reaching a state where it can be released).
Patch for ResourceManager.java
--------------------------------------------------------------------------
---
Apache-Velocity-20010131/src/java/org/apache/velocity/runtime/resource/ResourceManager.java
Wed Dec 20 00:57:20 2000
+++
+Apache-Velocity-20010126/src/java/org/apache/velocity/runtime/resource/ResourceManager.java
+ Fri Jan 26 16:44:06 2001
@@ -273,6 +273,7 @@
catch (Exception e)
{
Runtime.error(e);
+ resource = null; // return null
}
}
return resource;
--------------------------------------------------------------------------
Patch for VelocityServlet.java
--------------------------------------------------------------------------
--- Apache-Velocity-20010131/src/java/org/apache/velocity/servlet/VelocityServlet.java
Wed Jan 3 06:28:51 2001
+++ Apache-Velocity-20010126/src/java/org/apache/velocity/servlet/VelocityServlet.java
+ Thu Jan 25 17:26:12 2001
@@ -59,6 +59,7 @@
import java.io.Writer;
import java.io.BufferedWriter;
import java.io.OutputStreamWriter;
+import java.io.OutputStream;
import java.util.Stack;
@@ -80,7 +81,8 @@
/**
* Base class which simplifies the use of Velocity with Servlets.
- * Extend this class, implement the <code>handleRequest()</code> method,
+ * Extend this class, optionally implement the <code>prepareContext()</code>
+ * method, implement the <code>handleRequest()</code> method,
* and add your data to the context. Then call
* <code>getTemplate("myTemplate.wm")</code>.
*
@@ -91,8 +93,8 @@
* "res" - The HttpServletResponse object
* </pre>
*
- * If you put a contentType object into the context within either your
- * serlvet or within your template, then that will be used to override
+ * If you put a contentType object into the context within the
+ * <code>prepareContext()</code>, then that will be used to override
* the default content type specified in the properties file.
*
* "contentType" - The value for the Content-Type: header
@@ -102,7 +104,7 @@
* @author <a href="mailto:[EMAIL PROTECTED]">Geir Magnusson Jr.</a>
* $Id: VelocityServlet.java,v 1.20 2001/01/03 05:28:51 geirm Exp $
*/
-public abstract class VelocityServlet extends HttpServlet
+public class VelocityServlet extends HttpServlet
{
/**
* The HTTP request object context key.
@@ -138,7 +140,6 @@
/**
* Cache of writers
*/
-
private static SimplePool writerPool = new SimplePool(40);
/**
@@ -208,6 +209,23 @@
}
/**
+ * Prepare and process the request (this method may be
+ * overridden by subclasses).
+ */
+ protected Context prepareContext( HttpServletRequest request,
+ HttpServletResponse response )
+ {
+ // prepare the local context
+ VelocityContext context = new VelocityContext();
+
+ // put the request/response objects into the context
+ context.put(REQUEST, request);
+ context.put(RESPONSE, response);
+
+ return context;
+ }
+
+ /**
* Process the request.
*/
private void doRequest(HttpServletRequest request,
@@ -216,16 +234,11 @@
{
ServletOutputStream output = response.getOutputStream();
String contentType = null;
- VelocityWriter vw = null;
try
{
- // create a new context
- VelocityContext context = new VelocityContext();
-
- // put the request/response objects into the context
- context.put (REQUEST, request);
- context.put (RESPONSE, response);
+ // allow subclasses do perform different setups
+ Context context = prepareContext(request, response);
// check for a content type in the context
if (context.containsKey(CONTENT_TYPE))
@@ -245,7 +258,41 @@
if ( template == null )
throw new Exception ("Cannot find the template!" );
+ mergeTemplate( template, context, output );
+ }
+ catch (Exception e)
+ {
+ // display error messages
+ error( output, e.getMessage() );
+ }
+ finally
+ {
+ try
+ {
+ output.close();
+ }
+ catch(Exception e)
+ {
+ // do nothing
+ }
+ }
+ }
+
+ /**
+ * Merge a template with the context values to the output.
+ * This may be used in subclasses to ingest templates (e.g. to
+ * populate the context).<p>
+ * The closing of the OutputStream must be done by the caller.
+ */
+ protected void mergeTemplate( Template template,
+ Context context,
+ OutputStream output )
+ throws ServletException, IOException, Exception
+ {
+ VelocityWriter vw = null;
+ try
+ {
vw = (VelocityWriter) writerPool.get();
if (vw == null)
@@ -256,11 +303,6 @@
template.merge( context, vw);
}
- catch (Exception e)
- {
- // display error messages
- error (output, e.getMessage());
- }
finally
{
try
@@ -269,7 +311,6 @@
{
vw.flush();
writerPool.put(vw);
- output.close();
}
}
catch (Exception e)
@@ -297,10 +338,16 @@
* calling the <code>getTemplate()</code> method to produce your return
* value.
*
- * @param ctx The context to add your data to.
+ * @param context The context to add your data to.
* @return The template to merge with your context.
*/
- protected abstract Template handleRequest( Context ctx );
+ protected Template handleRequest( Context context ) throws Exception
+ {
+ String templateName =
+ ((HttpServletRequest) context.get(REQUEST)).getPathInfo();
+
+ return getTemplate(templateName);
+ }
/**
* Send an error message to the client.
@@ -318,4 +365,3 @@
out.print( html.toString() );
}
}
-
--------------------------------------------------------------------------
:) Christoph
