com.atlassian.johnson.context

Class JohnsonContextListener

java.lang.Object

com.atlassian.johnson.context.JohnsonContextListener

All Implemented Interfaces:

EventListener, javax.servlet.ServletContextListener

public class JohnsonContextListener
extends Object
implements javax.servlet.ServletContextListener

Initialises and terminates Johnson with the servlet container.

In web environments, this is the preferred mechanism for managing Johnson's lifecycle, allowing it to be initialised and terminated in a thread-safe context. This listener should be registered before any others except, if applicable, those that setup logging.

To use this listener, add the following to web.xml:

 <listener>
     <listener-class>com.atlassian.johnson.context.JohnsonContextListener</listener-class>
 </listener>
 
 

Alternatively, if the application is deployed in a Servlet 3 container such as Tomcat 7, this listener can be registered in a ServletContainerInitializer using ServletContext.addListener.

Since:

2.0

Field Summary

Fields

Modifier and Type	Field and Description
static String	ATTR_REGISTERED When a JohnsonContextListener is registered with a ServletContext, this attribute will be used to mark its registration so that multiple listeners will not be registered.

Constructor Summary

Constructors

Constructor and Description
JohnsonContextListener()

Method Summary

Modifier and Type	Method and Description
void	contextDestroyed(javax.servlet.ServletContextEvent event) Terminates Johnson.
void	contextInitialized(javax.servlet.ServletContextEvent event) Initialises Johnson.
static void	register(javax.servlet.ServletContext context) Registers a JohnsonContextListener with the provided ServletContext if such a listener has not already been registered.

Methods inherited from class java.lang.Object

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

Field Detail

ATTR_REGISTERED

public static final String ATTR_REGISTERED

When a JohnsonContextListener is registered with a ServletContext, this attribute will be used to mark its registration so that multiple listeners will not be registered.

Since:

3.0

Constructor Detail

JohnsonContextListener

public JohnsonContextListener()

Method Detail

register

public static void register(@Nonnull
                            javax.servlet.ServletContext context)

Registers a JohnsonContextListener with the provided ServletContext if such a listener has not already been registered.

This method is for use as part of Servlet 3-style ServletContainerInitializer initialization. Listeners cannot be added to ServletContext instances after they have already been initialized.

Parameters:

context - the ServletContext to register a JohnsonContextListener with

Throws:

IllegalArgumentException - if the provided ServletContext was not passed to ServletContainerInitializer.onStartup(java.util.Set, ServletContext)

IllegalStateException - if the ServletContext has already been initialized

UnsupportedOperationException - if this ServletContext was passed to the ServletContextListener.contextInitialized(ServletContextEvent) method of a ServletContextListener that was not either declared in web.xml or web-fragment.xml or annotated with @WebListener

Since:

3.0

contextDestroyed

public void contextDestroyed(@Nonnull
                             javax.servlet.ServletContextEvent event)

Terminates Johnson.

Specified by:

contextDestroyed in interface javax.servlet.ServletContextListener

Parameters:

event - the context event

See Also:

Johnson.terminate(javax.servlet.ServletContext)

contextInitialized

public void contextInitialized(@Nonnull
                               javax.servlet.ServletContextEvent event)

Initialises Johnson.

Specified by:

contextInitialized in interface javax.servlet.ServletContextListener

Parameters:

event - the context event

See Also:

Johnson.initialize(javax.servlet.ServletContext)