net.gini.dropwizard.gelf.filters

Class GelfLoggingFilter

java.lang.Object

net.gini.dropwizard.gelf.filters.GelfLoggingFilter

All Implemented Interfaces:

javax.servlet.Filter

public class GelfLoggingFilter
extends Object
implements javax.servlet.Filter

A Filter which logs requests and adds some data about it to the logger's MDC.

Constructor Summary

Constructors

Constructor and Description
GelfLoggingFilter()

Method Summary

Modifier and Type	Method and Description
void	destroy() Called by the web container to indicate to a filter that it is being taken out of service.
void	doFilter(javax.servlet.ServletRequest request, javax.servlet.ServletResponse response, javax.servlet.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.
void	init(javax.servlet.FilterConfig filterConfig) Called by the web container to indicate to a filter that it is being placed into service.

Methods inherited from class java.lang.Object

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

Constructor Detail

GelfLoggingFilter

public GelfLoggingFilter()

Method Detail

init

public void init(javax.servlet.FilterConfig filterConfig)
          throws javax.servlet.ServletException

Called by the web container to indicate to a filter that it is being placed into service.

The servlet container calls the init method exactly once after instantiating the filter. The init method must complete successfully before the filter is asked to do any filtering work.

The web container cannot place the filter into service if the init method either

1. Throws a ServletException
2. Does not return within a time period defined by the web container

Specified by:

init in interface javax.servlet.Filter

Parameters:

filterConfig - the FilterChain for this Filter

Throws:

javax.servlet.ServletException - if something goes wrong

doFilter

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

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. • Either invoke the next entity in the chain using the FilterChain object (chain.doFilter()),
   • 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.

Specified by:

doFilter in interface javax.servlet.Filter

Throws:

IOException

javax.servlet.ServletException

destroy

public void destroy()

Called by the web container to indicate to a filter that it is being taken out of service.

This method is only called once all threads within the filter's doFilter method have exited or after a timeout period has passed. After the web container calls this method, it will not call the doFilter method again on this instance of the filter.

This method gives the filter an opportunity to clean up any resources that are being held (for example, memory, file handles, threads) and make sure that any persistent state is synchronized with the filter's current state in memory.

Specified by:

destroy in interface javax.servlet.Filter