SessionInitializerFilter (Apache Tomcat 7.0.109 API Documentation)

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 and Description

SessionInitializerFilter()

Constructors
Constructor and Description
`SessionInitializerFilter()`

Method Summary

Methods
Modifier and Type	Method and 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 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: 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: 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

Class SessionInitializerFilter

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

SessionInitializerFilter

Method Detail

doFilter

init

destroy