com.anaptecs.jeaf.fastlane.impl

Class GracefulShutdownFilter

java.lang.Object

com.anaptecs.jeaf.fastlane.impl.GracefulShutdownFilter

All Implemented Interfaces:

javax.servlet.Filter

@WebFilter(value="/*",
           asyncSupported=true,
           displayName="Graceful Shutdown Filter")
public class GracefulShutdownFilter
extends Object
implements javax.servlet.Filter

Constructor Summary

Constructors

Constructor and Description
GracefulShutdownFilter()

Method Summary

Modifier and Type	Method and Description
int	decrementActiveRequestCounter() Method decrements the request counter by one.
void	destroy() Method will be called before the filter is finally deleted.
void	doFilter(javax.servlet.ServletRequest pRequest, javax.servlet.ServletResponse pResponse, javax.servlet.FilterChain pChain) Implementation of the concrete filtering.
int	getActiveRequestCounter() Method returns the current amount of active requests.
int	incrementActiveRequestCounter() Method increments the request counter by one.
void	init(javax.servlet.FilterConfig pFilterConfig) Initialize filter.
boolean	isShutdownRequested() Method returns if we are in the shutdown mode.
void	shutdownRequested(boolean pShutdownRequested) Method can be used to switch the filter into shutdown mode.

Methods inherited from class java.lang.Object

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

Constructor Detail

GracefulShutdownFilter

public GracefulShutdownFilter()

Method Detail

isShutdownRequested

public boolean isShutdownRequested()

Method returns if we are in the shutdown mode.

Returns:

boolean Method returns true if a shutdown was requested and false otherwise.

shutdownRequested

public void shutdownRequested(boolean pShutdownRequested)

Method can be used to switch the filter into shutdown mode. Shutdown mode means that all arriving requests will be rejected with HTTP status code SERVICE_UNAVAILABLE (503)

Parameters:

pShutdownRequested - Parameter will switch filter to shutdown mode in case that it is true and will disable shutdown mode if it is false.

incrementActiveRequestCounter

public int incrementActiveRequestCounter()

Method increments the request counter by one.

Returns:

int Current value of request counter after it was incremented.

decrementActiveRequestCounter

public int decrementActiveRequestCounter()

Method decrements the request counter by one.

Returns:

int Current value of request counter after it was decremented.

getActiveRequestCounter

public int getActiveRequestCounter()

Method returns the current amount of active requests.

Returns:

int Current amount of active requests.

init

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

Initialize filter.

Specified by:

init in interface javax.servlet.Filter

Throws:

javax.servlet.ServletException

doFilter

public void doFilter(javax.servlet.ServletRequest pRequest,
                     javax.servlet.ServletResponse pResponse,
                     javax.servlet.FilterChain pChain)
              throws IOException,
                     javax.servlet.ServletException

Implementation of the concrete filtering. In our case here we do the following things:

• In normal mode we just count the amount of active requests
• In shutdown mode reject incoming requests as we try to do a graceful shutdown

Specified by:

doFilter in interface javax.servlet.Filter

Throws:

IOException

javax.servlet.ServletException

destroy

public void destroy()

Method will be called before the filter is finally deleted.

Specified by:

destroy in interface javax.servlet.Filter