com.ervacon.springframework.web.servlet.mvc.webflow
Class WebFlowCleanupFilter

java.lang.Object
  org.springframework.web.filter.GenericFilterBean
      org.springframework.web.filter.OncePerRequestFilter
          com.ervacon.springframework.web.servlet.mvc.webflow.WebFlowCleanupFilter

All Implemented Interfaces:

javax.servlet.Filter

public class WebFlowCleanupFilter

extends org.springframework.web.filter.OncePerRequestFilter

Servlet 2.3 filter that cleans up expired web flows in the HTTP session associated with the request being filtered. A flow has expired when it has not handled any requests for more that a specified timeout period.

This filter can be configured in the web.xml deployment descriptor of your web application. Here's an example:

 <!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 	"http://java.sun.com/dtd/web-app_2_3.dtd">
 <web-app>
 	<filter>
 		<filter-name>webFlowCleanup</filter-name>
 		<filter-class>com.ervacon.springframework.web.servlet.mvc.webflow.WebFlowCleanupFilter</filter-class>
 	</filter>
 	<filter-mapping>
 		<filter-name>webFlowCleanup</filter-name>
 		<url-pattern>/*</url-pattern>
 	</filter-mapping>
 
 	...
 

Exposed configuration properties:

name	default	description
timeout	10	Specifies the flow timeout in minutes. If the flow is inactive for more that this period of time it will expire and be removed from the HTTP session.

These parameters can be configured using init-param values in the deployment descriptor.

Author:

Erwin Vervaet

Field Summary

static int

DEFAULT_TIMEOUT Default web flow timout: 10 minutes.

Fields inherited from class org.springframework.web.filter.OncePerRequestFilter

ALREADY_FILTERED_SUFFIX

Fields inherited from class org.springframework.web.filter.GenericFilterBean

logger

Constructor Summary

WebFlowCleanupFilter()

Method Summary

protected void	doCleanup(javax.servlet.http.HttpServletRequest request) Remove expired flows from the HTTP session associated with given request.
protected void	doFilterInternal(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, javax.servlet.FilterChain filterChain)
int	getTimeout() Get the flow timout (expiry), expressed in minutes.
protected boolean	hasExpired(javax.servlet.http.HttpServletRequest request, WebFlowMementoStack mementos) Check if given web flow memento stack, found in the session associated with given request, has expired.
void	setTimeout(int timeout) Set the flow timout (expiry), expressed in minutes.

Methods inherited from class org.springframework.web.filter.OncePerRequestFilter

doFilter, getAlreadyFilteredAttributeName, shouldNotFilter

Methods inherited from class org.springframework.web.filter.GenericFilterBean

addRequiredProperty, destroy, getFilterConfig, getFilterName, getServletContext, init, initBeanWrapper, initFilterBean, setFilterConfig

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_TIMEOUT

public static final int DEFAULT_TIMEOUT

Default web flow timout: 10 minutes.

See Also:

Constant Field Values

Constructor Detail

WebFlowCleanupFilter

public WebFlowCleanupFilter()

Method Detail

getTimeout

public int getTimeout()

Get the flow timout (expiry), expressed in minutes.

setTimeout

public void setTimeout(int timeout)

Set the flow timout (expiry), expressed in minutes.

doFilterInternal

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

Throws:

javax.servlet.ServletException

java.io.IOException

doCleanup

protected void doCleanup(javax.servlet.http.HttpServletRequest request)

Remove expired flows from the HTTP session associated with given request.

hasExpired

protected boolean hasExpired(javax.servlet.http.HttpServletRequest request,
                             WebFlowMementoStack mementos)

Check if given web flow memento stack, found in the session associated with given request, has expired.

Subclasses can override this method if they want to change the expiry logic, e.g. to keep flows alive in certain situations.

Parameters:

request - current HTTP request

mementos - the web flow memento stack that needs to be checked for expiry