Class 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 Detail

      • SessionInitializerFilter

        public SessionInitializerFilter()
    • Method Detail

      • 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