gov.noaa.pmel.tmap
Class TemplateServlet

java.lang.Object
  |
  +--VelocityServlet
        |
        +--gov.noaa.pmel.tmap.TemplateServlet

public class TemplateServlet

extends VelocityServlet

Servlet for Live Access Server user interface.

The LAS UI is generated from Velocity templates.

A HTTP request to the user interface is processed in the following order:

• The request is filtered by a set of servlet filters. These currently include the following classes:
  • FormFilter (handles POST requests)
  • SessionFilter (establishes and manages LAS user sessions)
  • ExceptionFilter (manages errors that occur in the servlet)
• The request is then sent to this class. The SessionFilter guarantees that a session has already been successfully established.
• The servlet looks for a class that implements the TemplateBean interface. A naming convention is used to find the class -- find any text after the last path separator in the URL, capitalize the first letter, and add "Bean" to the resulting string (i.e. the URL /las/dataset results in a search for DatasetBean). If the class exists, invoke a set of methods on the class.
• Merge the session TemplateContext with the local TemplateContext. For every UI request, a local TemplateContext is created that allows a developer to store parameters that will only be available for the current template. There is also a session TemplateContext that allows a developer to store parameters that are available to all templates in the current session. These contexts are merged (with the local TemplateContext having precedence if a namespace collision occurs).
• Invoke the Velocity template. The naming convention used to find the template is to find any text after the last path separator in the URL and add ".vm" to this string. The URL /las/dataset would cause invocation of the template "dataset.vm"

Version:

$Version$

Author:

$Author: kobrien $

See Also:

FormFilter, SessionFilter, ExceptionFilter, TemplateBean, Serialized Form

Constructor Summary

TemplateServlet()

Method Summary

protected void	error(HttpServletRequest request, HttpServletResponse response, java.lang.Exception cause) Override base VelocityServlet method to allow ExceptionFilter to catch Velocity template exceptions
(package private) TemplateBean	getBean(java.lang.String uri)
(package private) java.util.Vector	getBeanClassNames(java.lang.String uri)
Template	handleRequest(HttpServletRequest req, HttpServletResponse resp, Context ctx) Override base VelocityServlet method to allow special handling of template merging
void	init()
protected java.util.Properties	loadConfiguration(ServletConfig config)
protected void	mergeTemplate(Template template, Context context, HttpServletResponse response)
boolean	useTemplate()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

TemplateServlet

public TemplateServlet()

Method Detail

init

public void init()
          throws ServletException

ServletException

loadConfiguration

protected java.util.Properties loadConfiguration(ServletConfig config)
                                          throws java.io.IOException,
                                                 java.io.FileNotFoundException

java.io.IOException

java.io.FileNotFoundException

getBeanClassNames

java.util.Vector getBeanClassNames(java.lang.String uri)
                             throws ServletException,
                                    java.sql.SQLException

ServletException

java.sql.SQLException

useTemplate

public boolean useTemplate()

getBean

TemplateBean getBean(java.lang.String uri)
               throws ServletException,
                      java.sql.SQLException

ServletException

java.sql.SQLException

error

protected void error(HttpServletRequest request,
                     HttpServletResponse response,
                     java.lang.Exception cause)
              throws ServletException,
                     java.io.IOException

Override base VelocityServlet method to allow ExceptionFilter to catch Velocity template exceptions

ServletException

java.io.IOException

handleRequest

public Template handleRequest(HttpServletRequest req,
                              HttpServletResponse resp,
                              Context ctx)
                       throws ServletException,
                              java.io.IOException

Override base VelocityServlet method to allow special handling of template merging

ServletException

java.io.IOException

mergeTemplate

protected void mergeTemplate(Template template,
                             Context context,
                             HttpServletResponse response)
                      throws ServletException,
                             java.sql.SQLException,
                             java.io.IOException

ServletException

java.sql.SQLException

java.io.IOException