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java.lang.Objectorg.springframework.web.filter.GenericFilterBean
org.springframework.web.filter.DelegatingFilterProxy
public class DelegatingFilterProxy
Proxy for a standard Servlet 2.3 Filter, delegating to a Spring-managed
 bean that implements the Filter interface. Supports a "targetBeanName"
 filter init-param in web.xml, specifying the name of the
 target bean in the Spring application context.
 
web.xml will usually contain a DelegatingFilterProxy definition,
 with the specified filter-name corresponding to a bean name in
 Spring's root application context. All calls to the filter proxy will then
 be delegated to that bean in the Spring context, which is required to implement
 the standard Servlet 2.3 Filter interface.
 
This approach is particularly useful for Filter implementation with complex setup needs, allowing to apply the full Spring bean definition machinery to Filter instances. Alternatively, consider standard Filter setup in combination with looking up service beans from the Spring root application context.
NOTE: The lifecycle methods defined by the Servlet Filter interface
 will by default not be delegated to the target bean, relying on the
 Spring application context to manage the lifecycle of that bean. Specifying
 the "targetFilterLifecycle" filter init-param as "true" will enforce invocation
 of the Filter.init and Filter.destroy lifecycle methods
 on the target bean, letting the servlet container manage the filter lifecycle.
 
This class is inspired by Acegi Security's FilterToBeanProxy class, written by Ben Alex.
setTargetBeanName(java.lang.String), 
setTargetFilterLifecycle(boolean), 
Filter.doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain), 
Filter.init(javax.servlet.FilterConfig), 
Filter.destroy()| Field Summary | 
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| Fields inherited from class org.springframework.web.filter.GenericFilterBean | 
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| logger | 
| Constructor Summary | |
|---|---|
| DelegatingFilterProxy() | |
| Method Summary | |
|---|---|
|  void | destroy()Subclasses may override this to perform custom filter shutdown. | 
| protected  void | destroyDelegate(Filter delegate)Destroy the Filter delegate. | 
|  void | doFilter(ServletRequest request,
         ServletResponse response,
         FilterChain filterChain) | 
| protected  WebApplicationContext | findWebApplicationContext()Retrieve a WebApplicationContextfrom theServletContextattribute with theconfigured name. | 
|  String | getContextAttribute()Return the name of the ServletContext attribute which should be used to retrieve the WebApplicationContextfrom which to load the delegateFilterbean. | 
| protected  String | getTargetBeanName()Return the name of the target bean in the Spring application context. | 
| protected  Filter | initDelegate(WebApplicationContext wac)Initialize the Filter delegate, defined as bean the given Spring application context. | 
| protected  void | initFilterBean()Subclasses may override this to perform custom initialization. | 
| protected  void | invokeDelegate(Filter delegate,
               ServletRequest request,
               ServletResponse response,
               FilterChain filterChain)Actually invoke the delegate Filter with the given request and response. | 
| protected  boolean | isTargetFilterLifecycle()Return whether to invoke the Filter.initandFilter.destroylifecycle methods on the target bean. | 
|  void | setContextAttribute(String contextAttribute)Set the name of the ServletContext attribute which should be used to retrieve the WebApplicationContextfrom which to load the delegateFilterbean. | 
|  void | setTargetBeanName(String targetBeanName)Set the name of the target bean in the Spring application context. | 
|  void | setTargetFilterLifecycle(boolean targetFilterLifecycle)Set whether to invoke the Filter.initandFilter.destroylifecycle methods on the target bean. | 
| Methods inherited from class org.springframework.web.filter.GenericFilterBean | 
|---|
| addRequiredProperty, afterPropertiesSet, getFilterConfig, getFilterName, getServletContext, init, initBeanWrapper, setBeanName, setServletContext | 
| Methods inherited from class java.lang.Object | 
|---|
| clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait | 
| Constructor Detail | 
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public DelegatingFilterProxy()
| Method Detail | 
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public void setContextAttribute(String contextAttribute)
WebApplicationContext from which to load the delegate Filter bean.
public String getContextAttribute()
WebApplicationContext from which to load the delegate Filter bean.
public void setTargetBeanName(String targetBeanName)
By default, the filter-name as specified for the
 DelegatingFilterProxy in web.xml will be used.
protected String getTargetBeanName()
public void setTargetFilterLifecycle(boolean targetFilterLifecycle)
Filter.init and
 Filter.destroy lifecycle methods on the target bean.
 Default is "false"; target beans usually rely on the Spring application context for managing their lifecycle. Setting this flag to "true" means that the servlet container will control the lifecycle of the target Filter, with this proxy delegating the corresponding calls.
protected boolean isTargetFilterLifecycle()
Filter.init and
 Filter.destroy lifecycle methods on the target bean.
protected void initFilterBean()
                       throws ServletException
GenericFilterBeanNote: This method will be called from standard filter initialization as well as filter bean initialization in a Spring application context. Filter name and ServletContext will be available in both cases.
This default implementation is empty.
initFilterBean in class GenericFilterBeanServletException - if subclass initialization failsGenericFilterBean.getFilterName(), 
GenericFilterBean.getServletContext()
public void doFilter(ServletRequest request,
                     ServletResponse response,
                     FilterChain filterChain)
              throws ServletException,
                     IOException
ServletException
IOExceptionpublic void destroy()
GenericFilterBeanNote: This method will be called from standard filter destruction as well as filter bean destruction in a Spring application context.
This default implementation is empty.
destroy in interface Filterdestroy in interface DisposableBeandestroy in class GenericFilterBeanprotected WebApplicationContext findWebApplicationContext()
WebApplicationContext from the ServletContext
 attribute with the configured name. The
 WebApplicationContext must have already been loaded and stored in the
 ServletContext before this filter gets initialized (or invoked).
 Subclasses may override this method to provide a different
 WebApplicationContext retrieval strategy.
null if not foundgetContextAttribute()
protected Filter initDelegate(WebApplicationContext wac)
                       throws ServletException
Default implementation fetches the bean from the application context
 and calls the standard Filter.init method on it, passing
 in the FilterConfig of this Filter proxy.
wac - the root application context
ServletException - if thrown by the FiltergetTargetBeanName(), 
isTargetFilterLifecycle(), 
GenericFilterBean.getFilterConfig(), 
Filter.init(javax.servlet.FilterConfig)
protected void invokeDelegate(Filter delegate,
                              ServletRequest request,
                              ServletResponse response,
                              FilterChain filterChain)
                       throws ServletException,
                              IOException
delegate - the delegate Filterrequest - the current HTTP requestresponse - the current HTTP responsefilterChain - the current FilterChain
ServletException - if thrown by the Filter
IOException - if thrown by the Filterprotected void destroyDelegate(Filter delegate)
Filter.destroy on it.
delegate - the Filter delegate (never null)isTargetFilterLifecycle(), 
Filter.destroy()| 
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