com.atlassian.johnson.spring.web.filter

Class BypassableDelegatingFilterProxy

java.lang.Object

org.springframework.web.filter.GenericFilterBean

org.springframework.web.filter.DelegatingFilterProxy

com.atlassian.johnson.spring.web.filter.BypassableDelegatingFilterProxy

All Implemented Interfaces:

javax.servlet.Filter, org.springframework.beans.factory.Aware, org.springframework.beans.factory.BeanNameAware, org.springframework.beans.factory.DisposableBean, org.springframework.beans.factory.InitializingBean, org.springframework.context.EnvironmentAware, org.springframework.web.context.ServletContextAware

Direct Known Subclasses:

LifecycleDelegatingFilterProxy

public class BypassableDelegatingFilterProxy
extends org.springframework.web.filter.DelegatingFilterProxy

A more permissive subclass of Spring's DelegatingFilterProxy which bypasses the filter if there is no Spring WebApplicationContext available.

The default behaviour of the base class is to throw an IllegalStateException if, by the time the filter is invoked for the first time, no context is available. This subclass bypasses that behaviour and invokes the filter chain instead. This is necessary to allow redirects to the configured Johnson error page to make it through a filter chain which includes delegating filters.

Note: This class preserves the behaviour from the base class where the proxy will fail if it cannot find a bean with the correct name. It only suppresses failing if Spring is completely unavailable.

Field Summary

Fields inherited from class org.springframework.web.filter.GenericFilterBean

logger

Constructor Summary

Constructors

Constructor and Description
BypassableDelegatingFilterProxy()

Method Summary

Modifier and Type	Method and Description
void	doFilter(javax.servlet.ServletRequest request, javax.servlet.ServletResponse response, javax.servlet.FilterChain filterChain) Bypasses execution of the filter if no WebApplicationContext is available, delegating directly to the filter chain, or performs normal filtering if a context is available.
protected javax.servlet.Filter	initDelegate(org.springframework.web.context.WebApplicationContext wac) As an optimisation to this approach, once the delegate is initialised we set a flag indicating the filter is no longer bypassable.

Methods inherited from class org.springframework.web.filter.DelegatingFilterProxy

destroy, destroyDelegate, findWebApplicationContext, getContextAttribute, getTargetBeanName, initFilterBean, invokeDelegate, isTargetFilterLifecycle, setContextAttribute, setTargetBeanName, setTargetFilterLifecycle

Methods inherited from class org.springframework.web.filter.GenericFilterBean

addRequiredProperty, afterPropertiesSet, getFilterConfig, getFilterName, getServletContext, init, initBeanWrapper, setBeanName, setEnvironment, setServletContext

Methods inherited from class java.lang.Object

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

Constructor Detail

BypassableDelegatingFilterProxy

public BypassableDelegatingFilterProxy()

Method Detail

doFilter

public void doFilter(@Nonnull
                     javax.servlet.ServletRequest request,
                     @Nonnull
                     javax.servlet.ServletResponse response,
                     @Nonnull
                     javax.servlet.FilterChain filterChain)
              throws javax.servlet.ServletException,
                     IOException

Bypasses execution of the filter if no WebApplicationContext is available, delegating directly to the filter chain, or performs normal filtering if a context is available.

Once a WebApplicationContext is available once, this filter will never bypass again (even if, for some reason, the context later disappears).

Specified by:

doFilter in interface javax.servlet.Filter

Overrides:

doFilter in class org.springframework.web.filter.DelegatingFilterProxy

Parameters:

request - the servlet request to filter

response - the servlet response

filterChain - the filter chain

Throws:

javax.servlet.ServletException - May be thrown by the base class or the chain; never thrown locally.

IOException - May be thrown by the base class or the chain; never thrown locally.

initDelegate

protected javax.servlet.Filter initDelegate(org.springframework.web.context.WebApplicationContext wac)
                                     throws javax.servlet.ServletException

As an optimisation to this approach, once the delegate is initialised we set a flag indicating the filter is no longer bypassable. That way we don't continue to resolve the WebApplicationContext unnecessarily on every request.

Overrides:

initDelegate in class org.springframework.web.filter.DelegatingFilterProxy

Parameters:

wac - the resolved WebApplicationContext

Returns:

the targeted filter

Throws:

javax.servlet.ServletException - See documentation for the base class.

See Also:

DelegatingFilterProxy.initDelegate(org.springframework.web.context.WebApplicationContext)