# 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`
  `doFilter(ServletRequest request, ServletResponse response, FilterChain chain)`
  Calls `HttpServletRequest`'s getSession() to initialize the HttpSession and continues processing the chain.

  ### Methods inherited from class Object

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

  ### Methods inherited from interface Filter

  `destroy, init`

- ## 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