org.jsecurity.web.servlet
Class AdviceFilter

java.lang.Object
  org.jsecurity.web.servlet.ServletContextSupport
      org.jsecurity.web.servlet.OncePerRequestFilter
          org.jsecurity.web.servlet.AdviceFilter

All Implemented Interfaces:

Filter, Nameable

Direct Known Subclasses:

PathMatchingFilter

public abstract class AdviceFilter
extends OncePerRequestFilter

A Servlet Filter that enables AOP-style advice for a SerlvetRequest via preHandle, postHandle, and afterCompletion hooks.

Since:

0.9

Author:

Les Hazlewood

Field Summary

Fields inherited from class org.jsecurity.web.servlet.OncePerRequestFilter

ALREADY_FILTERED_SUFFIX, filterConfig

Constructor Summary

AdviceFilter()

Method Summary

void	afterCompletion(ServletRequest request, ServletResponse response, Exception exception) Called in all cases in a finally block even if preHandle returns false or if an exception is thrown during filter chain processing.
protected void	cleanup(ServletRequest request, ServletResponse response, Exception existing) Executes cleanup logic in the finally code block in the doFilterInternal implementation.
void	doFilterInternal(ServletRequest request, ServletResponse response, FilterChain chain) Actually implements the chain execution logic, utilizing pre, post, and after advice hooks.
protected void	executeChain(ServletRequest request, ServletResponse response, FilterChain chain) Actually executes the specified filter chain by calling chain.doFilter(request,response);.
protected void	postHandle(ServletRequest request, ServletResponse response) Allows 'post' advice logic to be called, but only if no exception occurs during filter chain execution.
protected boolean	preHandle(ServletRequest request, ServletResponse response) Returns true if the filter chain should be allowed to continue, false otherwise.

Methods inherited from class org.jsecurity.web.servlet.OncePerRequestFilter

destroy, doFilter, getAlreadyFilteredAttributeName, getFilterConfig, getName, init, onFilterConfigSet, setFilterConfig, setName, shouldNotFilter

Methods inherited from class org.jsecurity.web.servlet.ServletContextSupport

bind, getAttribute, getContextInitParam, getServletContext, removeAttribute, setAttribute, setServletContext

Methods inherited from class java.lang.Object

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

Constructor Detail

AdviceFilter

public AdviceFilter()

Method Detail

preHandle

protected boolean preHandle(ServletRequest request,
                            ServletResponse response)
                     throws Exception

Returns true if the filter chain should be allowed to continue, false otherwise. It is called before the chain is actually consulted/executed.

The default implementation returns true always and exists as a template method for subclasses.

Parameters:

request - the incoming ServletRequest

response - the outgoing ServletResponse

Returns:

true if the filter chain should be allowed to continue, false otherwise.

Throws:

Exception - if there is any error.

postHandle

protected void postHandle(ServletRequest request,
                          ServletResponse response)
                   throws Exception

Allows 'post' advice logic to be called, but only if no exception occurs during filter chain execution. That is, if executeChain throws an exception, this method will never be called. Be aware of this when implementing logic. Most resource 'cleanup' behavior is often done in the afterCompletion(request,response,exception) implementation, which is guaranteed to be called for every request, even when the chain processing throws an Exception.

The default implementation does nothing (no-op) and exists as a template method for subclasses.

Parameters:

request - the incoming ServletRequest

response - the outgoing ServletResponse

Throws:

Exception - if an error occurs.

afterCompletion

public void afterCompletion(ServletRequest request,
                            ServletResponse response,
                            Exception exception)
                     throws Exception

Called in all cases in a finally block even if preHandle returns false or if an exception is thrown during filter chain processing. Can be used for resource cleanup if so desired.

The default implementation does nothing (no-op) and exists as a template method for subclasses.

Parameters:

request - the incoming ServletRequest

response - the outgoing ServletResponse

exception - any exception thrown during preHandle, executeChain, or postHandle execution, or null if no exception was thrown (i.e. the chain processed successfully).

Throws:

Exception - if an error occurs.

executeChain

protected void executeChain(ServletRequest request,
                            ServletResponse response,
                            FilterChain chain)
                     throws Exception

Actually executes the specified filter chain by calling chain.doFilter(request,response);.

Can be overridden by subclasses for custom logic.

Parameters:

request - the incoming ServletRequest

response - the outgoing ServletResponse

chain - the filter chain to execute

Throws:

Exception - if there is any error executing the chain.

doFilterInternal

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

Actually implements the chain execution logic, utilizing pre, post, and after advice hooks.

Specified by:

doFilterInternal in class OncePerRequestFilter

Parameters:

request - the incoming ServletRequest

response - the outgoing ServletResponse

chain - the filter chain to execute

Throws:

ServletException - if a servlet-related error occurs

IOException - if an IO error occurs

cleanup

protected void cleanup(ServletRequest request,
                       ServletResponse response,
                       Exception existing)
                throws ServletException,
                       IOException

Executes cleanup logic in the finally code block in the doFilterInternal implementation.

This implementation specifically calls afterCompletion as well as handles any exceptions properly.

Parameters:

request - the incoming ServletRequest

response - the outgoing ServletResponse

existing - any exception that might have occurred while executing the FilterChain or pre or post advice, or null if the pre/chain/post excution did not throw an Exception.

Throws:

ServletException - if any exception other than an IOException is thrown.

IOException - if the pre/chain/post execution throw an IOException