Package org.apache.catalina.filters

Class SessionInitializerFilter

java.lang.Object

org.apache.catalina.filters.SessionInitializerFilter

All Implemented Interfaces:

Filter

public class SessionInitializerFilter
extends Object
implements Filter

A Filter that initializes the HttpSession for the HttpServletRequest by calling its getSession() method.

This is required for some operations with WebSocket requests, where it is too late to initialize the HttpSession object, and the current Java WebSocket specification does not provide a way to do so.

Constructor Summary

Constructors

Constructor	Description
SessionInitializerFilter()

Method Summary

Modifier and Type	Method	Description
void	destroy()	Called by the web container to indicate to a filter that it is being taken out of service.
void	doFilter(ServletRequest request, ServletResponse response, FilterChain chain)	Calls HttpServletRequest's getSession() to initialize the HttpSession and continues processing the chain.
void	init(FilterConfig filterConfig)	Called by the web container to indicate to a filter that it is being placed into service.

Methods inherited from class java.lang.Object

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

Constructor Details

SessionInitializerFilter

public SessionInitializerFilter()

Method Details

doFilter

public void doFilter(ServletRequest request,
 ServletResponse response,
 FilterChain chain)
              throws IOException,
ServletException

Calls HttpServletRequest's getSession() to initialize the HttpSession and continues processing the chain.

Specified by:

doFilter in interface Filter

Parameters:

request - The request to process

response - The response associated with the request

chain - Provides access to the next filter in the chain for this filter to pass the request and response to for further processing

Throws:

IOException - if an I/O error occurs during this filter's processing of the request

ServletException - if the processing fails for any other reason

init

public void init(FilterConfig filterConfig)
          throws ServletException

Description copied from interface: javax.servlet.Filter

Called by the web container to indicate to a filter that it is being placed into service. The servlet container calls the init method exactly once after instantiating the filter. The init method must complete successfully before the filter is asked to do any filtering work.

The web container cannot place the filter into service if the init method either:

• Throws a ServletException
• Does not return within a time period defined by the web container

Specified by:

init in interface Filter

Parameters:

filterConfig - The configuration information associated with the filter instance being initialised

Throws:

ServletException - if the initialisation fails

destroy

public void destroy()

Description copied from interface: javax.servlet.Filter

Called by the web container to indicate to a filter that it is being taken out of service. This method is only called once all threads within the filter's doFilter method have exited or after a timeout period has passed. After the web container calls this method, it will not call the doFilter method again on this instance of the filter.

This method gives the filter an opportunity to clean up any resources that are being held (for example, memory, file handles, threads) and make sure that any persistent state is synchronized with the filter's current state in memory.

Specified by:

destroy in interface Filter