HeaderFilterChain (Portlet 4.0 API Specification)

```
public interface HeaderFilterChain
```
A HeaderFilterChain object is provided by the portlet container to give a view into the invocation chain of a filtered header request for a portlet. Filters use the HeaderFilterChain to invoke the next filter in the chain, or if the calling filter is the last filter in the chain, to invoke the portlet at the end of the chain.

Since:

3.0

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`void`	`doFilter(HeaderRequest request, HeaderResponse response)`	Causes the next filter in the chain to be invoked, or if the calling filter is the last filter in the chain, causes the portlet at the end of the chain to be invoked.

- Method Detail
  - doFilter
```
void doFilter(HeaderRequest request,
              HeaderResponse response)
       throws IOException,
              PortletException
```
    Causes the next filter in the chain to be invoked, or if the calling filter is the last filter in the chain, causes the portlet at the end of the chain to be invoked.
    
    Parameters:
    
    request - the current header request.
    
    response - the current header response.
    
    Throws:
    
    IOException - if an IO error occurred in the filter processing
    
    PortletException - if a portlet exception occurred in the filter processing