# Class FailedRequestFilter

java.lang.Object
org.apache.catalina.filters.FilterBase
org.apache.catalina.filters.FailedRequestFilter

All Implemented Interfaces:
  `Filter`

public class FailedRequestFilter extends FilterBase
Filter that will reject requests if there was a failure during parameter parsing. This filter can be used to ensure that none parameter values submitted by client are lost.

Note that parameter parsing may consume the body of an HTTP request, so caution is needed if the servlet protected by this filter uses `request.getInputStream()` or `request.getReader()` calls. In general the risk of breaking a web application by adding this filter is not so high, because parameter parsing does check content type of the request before consuming the request body.

- ## Field Summary

  ### Fields inherited from class FilterBase

  `sm`

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `FailedRequestFilter()`

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `doFilter(ServletRequest request, ServletResponse response, FilterChain chain)`
  The `doFilter` method of the Filter is called by the container each time a request/response pair is passed through the chain due to a client request for a resource at the end of the chain.
  `protected Log`
  `getLogger()`
  Returns the logger for this filter.
  `protected boolean`
  `isConfigProblemFatal()`
  Determines if an exception when calling a setter or an unknown configuration attribute triggers the failure of this filter which in turn will prevent the web application from starting.

  ### Methods inherited from class FilterBase

  `init`

  ### Methods inherited from class Object

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

  ### Methods inherited from interface Filter

  `destroy`

- ## Constructor Details

  - ### FailedRequestFilter

    public FailedRequestFilter()

- ## Method Details

  - ### getLogger

    protected Log getLogger()
    Description copied from class: `FilterBase`
    Returns the logger for this filter.
    Specified by:
      `getLogger` in class `FilterBase`
    Returns:
      the logger

  - ### doFilter

    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException
    Description copied from interface: `javax.servlet.Filter`
    The `doFilter` method of the Filter is called by the container each time a request/response pair is passed through the chain due to a client request for a resource at the end of the chain. The FilterChain passed in to this method allows the Filter to pass on the request and response to the next entity in the chain.

    A typical implementation of this method would follow the following pattern:-
    1. Examine the request
    2. Optionally wrap the request object with a custom implementation to filter content or headers for input filtering
    3. Optionally wrap the response object with a custom implementation to filter content or headers for output filtering
    4. a) Either invoke the next entity in the chain using the FilterChain object (`chain.doFilter()`),
    4. b) or not pass on the request/response pair to the next entity in the filter chain to block the request processing
    5. Directly set headers on the response after invocation of the next entity in the filter chain.

    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

  - ### isConfigProblemFatal

    protected boolean isConfigProblemFatal()
    Description copied from class: `FilterBase`
    Determines if an exception when calling a setter or an unknown configuration attribute triggers the failure of this filter which in turn will prevent the web application from starting.
    Overrides:
      `isConfigProblemFatal` in class `FilterBase`
    Returns:
      `true` if a problem should trigger the failure of this filter, else `false`