freemarker.ext.servlet
Class FreeMarkerServlet

java.lang.Object
  javax.servlet.GenericServlet
      javax.servlet.http.HttpServlet
          freemarker.ext.servlet.FreeMarkerServlet

All Implemented Interfaces:

java.io.Serializable, javax.servlet.Servlet, javax.servlet.ServletConfig

public class FreeMarkerServlet
extends javax.servlet.http.HttpServlet

This is a general-purpose FreeMarker servlet with following features:

• It utilizes a TemplateCache that is fully parameterizable
• It makes all request, request parameters, session, and servlet context attributes available to templates through "Request", "RequestParameters", "Session", and "Application" variables. The implementation for these variables is efficient; rather than copying the attributes and parameters into FastHash, special wrapper classes are used that implement the TemplateHashModel interface.

Supported initialization parameters are:

• TemplatePath specifies the location of the templates. By default, the location is the web application-relative URI of the location. Alternatively, you can prepend it with file:// to indicate path in the file system (i.e. file:///var/www/project/templates/). Note that three slashes were specified. Default value is / (that is, the root of the web application).
• TemplateUpdateInterval value for update interval of the template cache in seconds. Default is 600 (ten minutes)
• TemplateMaximumAge the maximum age of a template in the cache before being expired. Default is 144 updates (~24 hours).
• NoCache if set to true, generates headers in the response that advise the HTTP client not to cache the returned page. Default false

Version:

$Id: FreeMarkerServlet.java 1101 2013-04-01 04:17:32Z run2000 $

Author:

Attila Szegedi, attila@szegedi.org

See Also:

Serialized Form

Field Summary

protected boolean	debug
protected int	maximumAge
static long	serialVersionUID Class UUID for serialization.
protected long	updateInterval

Constructor Summary

FreeMarkerServlet()

Method Summary

protected TemplateCache	createCache() Creates the TemplateCache to be used for this servlet.
protected HttpRequestParametersHashModel	createRequestParametersHashModel(javax.servlet.http.HttpServletRequest request) Get the request parameters from the servlet as a FreeMarker hash model.
void	doGet(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) Implement the "GET" method for HTTP requests.
void	doPost(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) Implement the "POST" method for HTTP requests.
protected java.lang.String	getTemplatePath() Retrieve the template path.
void	init() Initialise the servlet.
protected void	initializeServletContext(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) Called when servlet detects in a request processing that application-global (that is, ServletContext-specific) attributes are not yet set.
protected void	initializeSession(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) Called when servlet detects in a request processing that session-global (that is, HttpSession-specific) attributes are not yet set.
protected void	postTemplateProcess(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, Template template, TemplateWriteableHashModel data) Called after the execution returns from template.process().
protected boolean	preprocessRequest(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) Called as the first step in request processing, before the templating mechanism is put to work.
protected boolean	preTemplateProcess(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, Template template, TemplateWriteableHashModel data) Called before the execution is passed to template.process().

Methods inherited from class javax.servlet.http.HttpServlet

doDelete, doHead, doOptions, doPut, doTrace, getLastModified, service, service

Methods inherited from class javax.servlet.GenericServlet

destroy, getInitParameter, getInitParameterNames, getServletConfig, getServletContext, getServletInfo, getServletName, init, log, log

Methods inherited from class java.lang.Object

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

Field Detail

serialVersionUID

public static final long serialVersionUID

Class UUID for serialization.

See Also:

Constant Field Values

debug

protected boolean debug

updateInterval

protected long updateInterval

maximumAge

protected int maximumAge

Constructor Detail

FreeMarkerServlet

public FreeMarkerServlet()

Method Detail

init

public void init()

Initialise the servlet.

Overrides:

init in class javax.servlet.GenericServlet

createCache

protected TemplateCache createCache()

Creates the TemplateCache to be used for this servlet.

doGet

public void doGet(javax.servlet.http.HttpServletRequest request,
                  javax.servlet.http.HttpServletResponse response)
           throws javax.servlet.ServletException,
                  java.io.IOException

Implement the "GET" method for HTTP requests.

Overrides:

doGet in class javax.servlet.http.HttpServlet

Parameters:

request - the servlet request

response - the servlet response

Throws:

javax.servlet.ServletException

java.io.IOException

doPost

public void doPost(javax.servlet.http.HttpServletRequest request,
                   javax.servlet.http.HttpServletResponse response)
            throws javax.servlet.ServletException,
                   java.io.IOException

Implement the "POST" method for HTTP requests.

Overrides:

doPost in class javax.servlet.http.HttpServlet

Parameters:

request - the servlet request

response - the servlet response

Throws:

javax.servlet.ServletException

java.io.IOException

preprocessRequest

protected boolean preprocessRequest(javax.servlet.http.HttpServletRequest request,
                                    javax.servlet.http.HttpServletResponse response)
                             throws javax.servlet.ServletException,
                                    java.io.IOException

Called as the first step in request processing, before the templating mechanism is put to work. By default does nothing and returns false. This method is typically overridden to manage serving of non-template resources (i.e. images) that reside in template directory.

Parameters:

request - the HTTP request

response - the HTTP response

Returns:

true to indicate this method has processed the request entirely, and that the further request processing should not take place.

Throws:

javax.servlet.ServletException

java.io.IOException

getTemplatePath

protected final java.lang.String getTemplatePath()

Retrieve the template path. This is the root of the directory structure being cached by the TemplateCache.

Returns:

the template path being cached

createRequestParametersHashModel

protected HttpRequestParametersHashModel createRequestParametersHashModel(javax.servlet.http.HttpServletRequest request)

Get the request parameters from the servlet as a FreeMarker hash model.

Parameters:

request - the servlet request parameters as an HttpServletRequest

Returns:

the request parameters as a TemplateHashModel

initializeServletContext

protected void initializeServletContext(javax.servlet.http.HttpServletRequest request,
                                        javax.servlet.http.HttpServletResponse response)
                                 throws javax.servlet.ServletException,
                                        java.io.IOException

Called when servlet detects in a request processing that application-global (that is, ServletContext-specific) attributes are not yet set. This is a generic hook you might use in subclasses to perform a specific action on first request in the context. By default it does nothing.

Parameters:

request - the actual HTTP request

response - the actual HTTP response

Throws:

javax.servlet.ServletException

java.io.IOException

initializeSession

protected void initializeSession(javax.servlet.http.HttpServletRequest request,
                                 javax.servlet.http.HttpServletResponse response)
                          throws javax.servlet.ServletException,
                                 java.io.IOException

Called when servlet detects in a request processing that session-global (that is, HttpSession-specific) attributes are not yet set. This is a generic hook you might use in subclasses to perform a specific action on first request in the session. By default it does nothing.

Parameters:

request - the actual HTTP request

response - the actual HTTP response

Throws:

javax.servlet.ServletException

java.io.IOException

preTemplateProcess

protected boolean preTemplateProcess(javax.servlet.http.HttpServletRequest request,
                                     javax.servlet.http.HttpServletResponse response,
                                     Template template,
                                     TemplateWriteableHashModel data)
                              throws javax.servlet.ServletException,
                                     java.io.IOException

Called before the execution is passed to template.process(). This is a generic hook you might use in subclasses to perform a specific action before the template is processed. By default does nothing. A typical action to perform here is to inject application-specific objects into the TemplateWriteableHashModel.

Parameters:

request - the actual HTTP request

response - the actual HTTP response

template - the template that will get executed

data - the data that will be passed to the template

Returns:

true to process the template, false to suppress template processing.

Throws:

javax.servlet.ServletException

java.io.IOException

postTemplateProcess

protected void postTemplateProcess(javax.servlet.http.HttpServletRequest request,
                                   javax.servlet.http.HttpServletResponse response,
                                   Template template,
                                   TemplateWriteableHashModel data)
                            throws javax.servlet.ServletException,
                                   java.io.IOException

Called after the execution returns from template.process(). This is a generic hook you might use in subclasses to perform a specific action after the template is processed. It will be invoked even if the template processing throws an exception. By default does nothing.

Parameters:

request - the actual HTTP request

response - the actual HTTP response

template - the template that was executed

data - the data that was passed to the template

Throws:

javax.servlet.ServletException

java.io.IOException