Overview  Package   Class  Use  Tree  Deprecated  Index  Help 
 PREV CLASS   NEXT CLASS FRAMES    NO FRAMES
SUMMARY:  INNER | FIELD | CONSTR | METHOD DETAIL:  FIELD | CONSTR | METHOD

ca.cbc.sportwire.servlet
Class SportPageServlet

java.lang.Object
  |
  +--javax.servlet.GenericServlet
        |
        +--javax.servlet.http.HttpServlet
              |
              +--org.apache.velocity.servlet.VelocityServlet
                    |
                    +--ca.cbc.sportwire.servlet.VelocityEngineServlet
                          |
                          +--ca.cbc.sportwire.servlet.SportPageServlet
All Implemented Interfaces:
GlobalCacheProperties, java.io.Serializable, javax.servlet.Servlet, javax.servlet.ServletConfig, SportPageProperties
public class SportPageServlet
extends VelocityEngineServlet
implements GlobalCacheProperties, SportPageProperties

SportPageServlet: The primary Servlet for the Sports pages; the servlet is installed as the default page for the webapp, responding to the url-pattern "/" (see src/sportpage.xml).

The servlet extends the VelocityServlet, which leaves Velocity to manage all of the problems of making the connection, closing out the buffers and handling the doXXX methods. This servlet takes the Request URI as a cue to search for a corresponding class, beginning with the full URI path and working its way back dropping the last term until it arrives at PageHandler class -- this search may not be totally optimal as /baseball/update/minn may want to share Update.class instead of requiring a subclass baseball.Update; the search behaviour may evolve over time

Once a PageHandler is found (or we revert to the Default) that class is asked to set up the context; this is where the specific URI dictates the starting conditions for each page. For example baseball.Update would take the tail of the URI as some sort of game key value and would fetch the updates for that game, while also setting the $page variable to the template for baseball game updates. Since PageHandlers are invoked before any template rendering, even the layut template may be changed by these handlers.

This code is part of the open source SportWire News Aggregation and Display System - © 2001 The Canadian Broadcasting Corporation

Created: Thu Nov 29 16:47:42 2001 
 $Log: SportPageServlet.java,v $
 Revision 1.27  2002/01/29 19:33:44  garym
 fixed concurrency bug with global config

 Revision 1.26  2002/01/28 21:50:04  garym
 Improved critical error recovery; headlines now use backup script feed

 Revision 1.25  2002/01/27 06:39:57  garym
 Added XSL transform and XML output to JDOMFile

 Revision 1.24  2002/01/26 06:46:27  garym
 authorization bug in lineups

 Revision 1.23  2002/01/24 19:50:20  garym
 Major restructuring of beans and pagehandlers

 Revision 1.22  2002/01/22 22:34:46  garym
 Fixed news slug case bug

 Revision 1.21  2002/01/22 06:40:45  garym
 Bug fix to emergency error; not yet complete.

 Revision 1.20  2002/01/21 20:07:14  garym
 NewsPage did not include $news; fixed error reporting to be a redirect to 404

 Revision 1.19  2002/01/16 23:09:24  garym
 Implemented the JDBC pool support and sql property beans

 Revision 1.18  2002/01/16 00:56:26  garym
 current site on cbc.ca/olympics; checkpoint release

 Revision 1.17  2002/01/15 08:28:50  garym
 implemented MRU cache for the JDOMFile objects

 Revision 1.16  2002/01/14 21:51:46  garym
 bug fixes in topics and config files migration to Extended Properties

 Revision 1.15  2002/01/09 04:28:59  garym
 Added test unit stubs and new News support

 Revision 1.14  2002/01/04 06:12:46  garym
 default page handling of XML files obsolesces DOMPageHandler

 Revision 1.13  2001/12/23 17:55:21  garym
 Allow for multiple SportPage apps on one JVM

 Revision 1.12  2001/12/23 04:54:16  garym
 Added TemplateLineup support and Velocity logfile setting

 Revision 1.11  2001/12/18 16:48:39  garym
 Adapted to VelocityEngine

 Revision 1.10  2001/12/16 22:01:56  garym
 fixes to default page handling

 Revision 1.9  2001/12/15 02:15:58  garym
 initial release to CBC staging server

 Revision 1.8  2001/12/14 21:12:29  garym
 include file debugging

 Revision 1.7  2001/12/13 06:48:40  garym
 Implemented a path object that can break up the elements of the path

 Revision 1.6  2001/12/08 02:53:15  garym
 Defaults are overlaid with the topic defaults

 Revision 1.5  2001/12/06 16:29:51  garym
 Implemented DOM object support and the Bio page handler

 Revision 1.4  2001/12/06 07:26:39  garym
 Genertes simple layouts; page parts in Properties

 Revision 1.3  2001/12/06 04:57:59  garym
 DefaultPage now take template parts from properties

 Revision 1.2  2001/12/01 05:08:21  garym
 Updated documentation

 Revision 1.1  2001/12/01 04:02:40  garym
 Initial SportPageServlet files with sample templates

Version:
$Id: SportPageServlet.java,v 1.27 2002/01/29 19:33:44 garym Exp $
Author:
Gary Lawrence Murphy
See Also:
Serialized Form

Field Summary
private  org.apache.commons.collections.ExtendedProperties appConfig
           
(package private) static org.apache.log4j.Category cat
           
private  boolean loginit
          startLog loads filters and appenders from the property file specified by sportpage.log4j.conf.
private  MRUCacheMap mruCache
           
private  TTLCacheMap ttlCache
           
 
Fields inherited from class ca.cbc.sportwire.servlet.VelocityEngineServlet
defaultContentType, encoding, INIT_PROPS_KEY, servletConfig, velocity, writerPool
 
Fields inherited from class org.apache.velocity.servlet.VelocityServlet
CONTENT_TYPE, DEFAULT_CONTENT_TYPE, DEFAULT_OUTPUT_ENCODING, REQUEST, RESPONSE
 
Fields inherited from class javax.servlet.http.HttpServlet
HEADER_IFMODSINCE, HEADER_LASTMOD, LSTRING_FILE, lStrings, METHOD_DELETE, METHOD_GET, METHOD_HEAD, METHOD_OPTIONS, METHOD_POST, METHOD_PUT, METHOD_TRACE
 
Fields inherited from class javax.servlet.GenericServlet
config
 
Fields inherited from interface ca.cbc.sportwire.servlet.data.GlobalCacheProperties
CACHE_DEFAULT_PERIOD, CACHE_DEFAULT_TIMEOUT, CACHE_PERIOD, CACHE_TIMEOUT, MRU_PROPERTY, MRU_VAR, TTL_PROPERTY, TTL_VAR
 
Fields inherited from interface ca.cbc.sportwire.servlet.data.SportPageProperties
BEAN_SUFFIX, BEANFACTORY_VAR, CONTEXT_VAR, DATE_VAR, DEFAULT_EXTS, DEFAULT_INDEXES, DEFAULT_PAGE_SUFFIX, DEFAULT_SAX_DRIVER_CLASS, DEFAULT_TIMEZONE, DEFAULT_TOPIC, DOM_VAR, ERROR_TEMPLATE_VAR, EXCEPTION_VAR, EXTENSIONS_VAR, FALSE, GLOBAL_VAR, HOME_PROPERTY, INCLUDE_EXTS_PROPERTY, INCLUDE_VAR, INDEX_INDICATOR_VAR, INDEX_TEMPLATE_VAR, LAYOUT_TEMPLATE_VAR, MACRO_LIB_PROPERTY, MISSING_TEMPLATE_VAR, OUTPUT_VAR, PAGE_EXPIRE, PAGE_TEMPLATE_VAR, PANIC_404_PAGE, PANIC_404_PROPERTY, PANIC_500_PAGE, PANIC_500_PROPERTY, PARAM_PARSER_VAR, PATH_VAR, REQUEST_VAR, RESPONSE_VAR, SAX_CLASS_PROPERTY, SERVLET_DEBUG, SERVLET_LOGCONF_PROPERTY, SQL_SUFFIX, TEMPLATE_PATHS_PROPERTY, TIMEZONE_PROPERTY, TRUE, URI_VAR, VELOCITY_LOGFILE_DEFAULT, VELOCITY_LOGFILE_PROPERTY, XML_EXTS, XML_EXTS_PROPERTY, XML_PATHS_PROPERTY, XML_SUFFIX, XSL_EXTS, XSL_EXTS_PROPERTY, XSL_PATHS_PROPERTY
 
Constructor Summary
SportPageServlet()
           
 
Method Summary
protected  void error(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, java.lang.Exception cause)
          error: Currently minimcally implemented to avoid ugly Velocity stack-trace screens; should be expanded later to provide a more graceful reaction to different classes of critical template errors.
 org.apache.commons.collections.ExtendedProperties getAppConfig()
          appConfig is the application-wide configuration; servletContext is not guaranteed to be unique to each servlet (although it can be) so the global properties loaded for the servlet are stored here; anyone got a better place?
 MRUCacheMap getMruCache()
          Get the value of mruCache.
 java.lang.String getServletInfo()
          getServletInfo: Returns the version ID of this file
protected  java.lang.StringBuffer getTemplatePath()
           
 TTLCacheMap getTTLCache()
          Get the value of ttlCache.
 org.apache.velocity.Template handleRequest(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse res, org.apache.velocity.context.Context context)
          handleRequest: Velocity main request method.
protected  boolean handleStaticRequest(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse res, org.apache.velocity.context.Context context)
          handleStaticRequest: For the time being, we have a problem where static files referenced in the templates cannot be handled by Apache because the root /sports in the URL causes Apache to hand it over (JkMount) to tomcat, and tomcat hands it back to this servlet (because of the '/' url-pattern.
protected  java.util.Properties loadConfiguration(javax.servlet.ServletConfig config)
          loadConfiguration: fetch the properties in the file specified by sportpage.servlet.conf (in WEB-INF/web.xml) and add them to the ServletContext, and load up the Velocity configuration (which can be specified seperately as a "properties" web.xml init-param value.
protected  void mergeTemplate(org.apache.velocity.Template template, org.apache.velocity.context.Context context, javax.servlet.http.HttpServletResponse response)
          mergeTemplate: Overriding this method allows us to trap errors in the execution of the templates and shunt the page off to a standard site error page instead of returning the default stacktrace error page.
protected  void setAppConfig(org.apache.commons.collections.ExtendedProperties v)
          Set the value of appConfig.
protected  TTLCacheMap setCache(java.lang.String cacheVar, TTLCacheMap cache)
           
protected  void setMruCache(MRUCacheMap v)
          Set the value of mruCache.
protected  void setPathProperties(java.lang.String uri, org.apache.velocity.context.Context context)
          setPathProperties: stuffs the context with variables based on the URI: requestURI is the full URI of this webapp path is the path after this webapp as a ca.cbc.sportpage.servlet.data.PathBean object.
protected  void setTTLCache(TTLCacheMap v)
          Set the value of ttlCache.
protected  void startLog(java.lang.String home)
           
 
Methods inherited from class ca.cbc.sportwire.servlet.VelocityEngineServlet
doRequest, getServletConfig, getTemplate, getTemplate, getVelocity, init, setContentType, setVelocity
 
Methods inherited from class org.apache.velocity.servlet.VelocityServlet
, createContext, doGet, doPost, handleRequest, requestCleanup
 
Methods inherited from class javax.servlet.http.HttpServlet
doDelete, doHead, doOptions, doPut, doTrace, getAllDeclaredMethods, getLastModified, maybeSetLastModified, service, service
 
Methods inherited from class javax.servlet.GenericServlet
destroy, getInitParameter, getInitParameterNames, getServletContext, getServletName, init, log, log
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, registerNatives, toString, wait, wait, wait
 

Field Detail

cat

static org.apache.log4j.Category cat

appConfig

private org.apache.commons.collections.ExtendedProperties appConfig

mruCache

private MRUCacheMap mruCache

ttlCache

private TTLCacheMap ttlCache

loginit

private boolean loginit
startLog loads filters and appenders from the property file specified by sportpage.log4j.conf. If sportpage.debug is false, messages below WARN priority will be suppressed. This can be undone in a production release through the log4j.disableOverride property.
Constructor Detail

SportPageServlet

public SportPageServlet()
Method Detail

getAppConfig

public org.apache.commons.collections.ExtendedProperties getAppConfig()
appConfig is the application-wide configuration; servletContext is not guaranteed to be unique to each servlet (although it can be) so the global properties loaded for the servlet are stored here; anyone got a better place?
Returns:
SportwireConfig value of appConfig.

setAppConfig

protected void setAppConfig(org.apache.commons.collections.ExtendedProperties v)
Set the value of appConfig. This is only called by the servlet init so the result is common to all invocations of this servlet.
Parameters:
v - ExtendedProperties object to assign to appConfig.

getMruCache

public MRUCacheMap getMruCache()
Get the value of mruCache.
Returns:
MRUCacheMap value of mruCache.

setMruCache

protected void setMruCache(MRUCacheMap v)
Set the value of mruCache.
Parameters:
v - Value to assign to mruCache.

getTTLCache

public TTLCacheMap getTTLCache()
Get the value of ttlCache.
Returns:
TTLCacheMap value of ttlCache.

setTTLCache

protected void setTTLCache(TTLCacheMap v)
Set the value of ttlCache.
Parameters:
v - Value to assign to ttlCache.

setCache

protected TTLCacheMap setCache(java.lang.String cacheVar,
                               TTLCacheMap cache)

getTemplatePath

protected java.lang.StringBuffer getTemplatePath()

loadConfiguration

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

loadConfiguration: fetch the properties in the file specified by sportpage.servlet.conf (in WEB-INF/web.xml) and add them to the ServletContext, and load up the Velocity configuration (which can be specified seperately as a "properties" web.xml init-param value. This method is only called once, when the Servlet is created.

The SportPageServlet pre-seeds the Velocity engine with the following properties taken from the SportPage configuration file specified as spotpage.servlet.conf in the web.xml:
templates.home
if missing, this defaults to the webapp's directory; otherwise this is added to Velocity.RESOURCE_LOADER_PATH
home
gets set to the base webapp directory
Overrides:
loadConfiguration in class org.apache.velocity.servlet.VelocityServlet
Parameters:
config - the current ServletConfig value
Returns:
a Properties value used to set Velocity
Throws:
java.io.IOException - if an error occurs reading the file
java.io.FileNotFoundException - if no config exists

mergeTemplate

protected void mergeTemplate(org.apache.velocity.Template template,
                             org.apache.velocity.context.Context context,
                             javax.servlet.http.HttpServletResponse response)
                      throws org.apache.velocity.exception.ResourceNotFoundException,
                             org.apache.velocity.exception.ParseErrorException,
                             org.apache.velocity.exception.MethodInvocationException,
                             java.io.IOException,
                             java.io.UnsupportedEncodingException,
                             java.lang.Exception
mergeTemplate: Overriding this method allows us to trap errors in the execution of the templates and shunt the page off to a standard site error page instead of returning the default stacktrace error page.
Overrides:
mergeTemplate in class VelocityEngineServlet
Parameters:
template - a Velocity Template value
context - a Velocity Context value
response - a HttpServletResponse value
Throws:
org.apache.velocity.exception.ResourceNotFoundException - if no template is found
org.apache.velocity.exception.ParseErrorException - if the template has syntax errors
org.apache.velocity.exception.MethodInvocationException - if the template makes an illegel call to some embedded object
java.io.IOException - if we cannot write to the output port.
java.io.UnsupportedEncodingException - if the template has invalid chars
java.lang.Exception - if an unknown error occurs

error

protected void error(javax.servlet.http.HttpServletRequest request,
                     javax.servlet.http.HttpServletResponse response,
                     java.lang.Exception cause)
              throws javax.servlet.ServletException,
                     java.io.IOException
error: Currently minimcally implemented to avoid ugly Velocity stack-trace screens; should be expanded later to provide a more graceful reaction to different classes of critical template errors. Current method just uses a meta-tag to redirect to a standard 404 error page configured by panic.404=error.html config property, and prints the stack trace in a comment. Keep in mind that this must redirect outside of the webapp URI space to prevent recursive error reporting.
Overrides:
error in class org.apache.velocity.servlet.VelocityServlet
Parameters:
request - a HttpServletRequest value
response - a HttpServletResponse value
cause - an Exception value
Throws:
javax.servlet.ServletException - if an error occurs
java.io.IOException - if an error occurs

setPathProperties

protected void setPathProperties(java.lang.String uri,
                                 org.apache.velocity.context.Context context)
setPathProperties: stuffs the context with variables based on the URI:
Parameters:
uri - a String RequestURI
context - a Velocity Context
See Also:
ca.cbc.sportpage.servlet.data.PathBean

handleStaticRequest

protected boolean handleStaticRequest(javax.servlet.http.HttpServletRequest req,
                                      javax.servlet.http.HttpServletResponse res,
                                      org.apache.velocity.context.Context context)
handleStaticRequest: For the time being, we have a problem where static files referenced in the templates cannot be handled by Apache because the root /sports in the URL causes Apache to hand it over (JkMount) to tomcat, and tomcat hands it back to this servlet (because of the '/' url-pattern. A dilemma. Many files we would naturally import have relative paths to icons and other images. This method is a temp hack fix: if we suspect the URI intends to receive a static item, we load it and blast it back at them. At the present time, we only recognize GIF and JPG files.
Parameters:
req - a HttpServletRequest value
res - a HttpServletResponse value
context - a Velocity Context
Returns:
a boolean true if we handled it

handleRequest

public org.apache.velocity.Template handleRequest(javax.servlet.http.HttpServletRequest req,
                                                  javax.servlet.http.HttpServletResponse res,
                                                  org.apache.velocity.context.Context context)
                                           throws java.io.IOException
handleRequest: Velocity main request method. This method returns the template to process, or returns null if the request was handled by some other means (such as dumping a file back).
Overrides:
handleRequest in class org.apache.velocity.servlet.VelocityServlet
Parameters:
req - a HttpServletRequest
res - a HttpServletResponse
context - a Velocity Context
Returns:
a Velocity Template
Throws:
java.io.IOException - if an error occurs

getServletInfo

public java.lang.String getServletInfo()
getServletInfo: Returns the version ID of this file
Overrides:
getServletInfo in class javax.servlet.GenericServlet
Returns:
a String value

startLog

protected void startLog(java.lang.String home)
Overview  Package   Class  Use  Tree  Deprecated  Index  Help 
 PREV CLASS   NEXT CLASS FRAMES    NO FRAMES
SUMMARY:  INNER | FIELD | CONSTR | METHOD DETAIL:  FIELD | CONSTR | METHOD

Javadocs generated Tue Apr 23 01:08:36 EDT 2002 by garym@maya.dyndns.org
Copyright © 2002 Canadian Broadcasting Corp