com.atlassian.johnson.spring.web.servlet

Class JohnsonDispatcherServlet

java.lang.Object

javax.servlet.GenericServlet

javax.servlet.http.HttpServlet

org.springframework.web.servlet.HttpServletBean

org.springframework.web.servlet.FrameworkServlet

org.springframework.web.servlet.DispatcherServlet

com.atlassian.johnson.spring.web.servlet.JohnsonDispatcherServlet

All Implemented Interfaces:

Serializable, javax.servlet.Servlet, javax.servlet.ServletConfig, org.springframework.beans.factory.Aware, org.springframework.context.EnvironmentAware, org.springframework.core.env.EnvironmentCapable

public class JohnsonDispatcherServlet
extends org.springframework.web.servlet.DispatcherServlet

Extends the standard Spring DispatcherServlet to make it Johnson-aware. When using this class, if the root Spring context fails to start the dispatcher will not attempt to create/start its child context.

The goal of this class is to prevent the web application from being shutdown if SpringMVC cannot be started. By default, if the dispatcher's WebApplicationContext cannot be started for any reason, an exception is thrown which is propagated up to the container. When this happens, the entire web application is terminated. This precludes the use of Johnson, which requires that the web application be up so that it can serve its status pages.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static String	PREFIX_BYPASSED The prefix for the attribute added to the ServletContext when Spring MVC initialization is bypassed because a previous Event indicates the application has already failed.

Fields inherited from class org.springframework.web.servlet.DispatcherServlet

FLASH_MAP_MANAGER_ATTRIBUTE, FLASH_MAP_MANAGER_BEAN_NAME, HANDLER_ADAPTER_BEAN_NAME, HANDLER_EXCEPTION_RESOLVER_BEAN_NAME, HANDLER_MAPPING_BEAN_NAME, INPUT_FLASH_MAP_ATTRIBUTE, LOCALE_RESOLVER_ATTRIBUTE, LOCALE_RESOLVER_BEAN_NAME, MULTIPART_RESOLVER_BEAN_NAME, OUTPUT_FLASH_MAP_ATTRIBUTE, PAGE_NOT_FOUND_LOG_CATEGORY, pageNotFoundLogger, REQUEST_TO_VIEW_NAME_TRANSLATOR_BEAN_NAME, THEME_RESOLVER_ATTRIBUTE, THEME_RESOLVER_BEAN_NAME, THEME_SOURCE_ATTRIBUTE, VIEW_RESOLVER_BEAN_NAME, WEB_APPLICATION_CONTEXT_ATTRIBUTE

Fields inherited from class org.springframework.web.servlet.FrameworkServlet

DEFAULT_CONTEXT_CLASS, DEFAULT_NAMESPACE_SUFFIX, SERVLET_CONTEXT_PREFIX

Fields inherited from class org.springframework.web.servlet.HttpServletBean

logger

Constructor Summary

Constructors

Constructor and Description
JohnsonDispatcherServlet()
JohnsonDispatcherServlet(org.springframework.web.context.WebApplicationContext webApplicationContext)

Method Summary

Modifier and Type	Method and Description
protected Event	createEvent(String defaultEventType, String defaultMessage, Throwable t) May be overridden in derived classes to allow them to override the default event type or message based on application-specific understanding of the exception that was thrown.
void	destroy() Performs standard SpringMVC DispatcherServlet teardown and ensures any attributes added to the servlet context for this dispatcher are removed.
protected String	getBypassedAttributeName() Allows derived classes to override the name of the attribute which is added to the ServletContext when this dispatcher is bypassed (whether due to the JohnsonContextLoaderListener being bypassed or due to the initialisation of the dispatcher failing).
protected org.springframework.web.context.WebApplicationContext	initWebApplicationContext() Overrides the standard SpringMVC DispatcherServlet initialisation to make it Johnson-aware, allowing it to be automatically bypassed, when paired with a JohnsonContextLoaderListener, or add an Event if initialisation fails.

Methods inherited from class org.springframework.web.servlet.DispatcherServlet

buildLocaleContext, checkMultipart, cleanupMultipart, createDefaultStrategy, doDispatch, doService, getDefaultStrategies, getDefaultStrategy, getDefaultViewName, getHandler, getHandler, getHandlerAdapter, getMultipartResolver, getThemeSource, initStrategies, noHandlerFound, onRefresh, processHandlerException, render, resolveViewName, setCleanupAfterInclude, setDetectAllHandlerAdapters, setDetectAllHandlerExceptionResolvers, setDetectAllHandlerMappings, setDetectAllViewResolvers

Methods inherited from class org.springframework.web.servlet.FrameworkServlet

applyInitializers, buildRequestAttributes, configureAndRefreshWebApplicationContext, createWebApplicationContext, createWebApplicationContext, doDelete, doGet, doOptions, doPost, doPut, doTrace, findWebApplicationContext, getContextAttribute, getContextClass, getContextConfigLocation, getContextId, getNamespace, getServletContextAttributeName, getUsernameForRequest, getWebApplicationContext, initFrameworkServlet, initServletBean, onApplicationEvent, postProcessWebApplicationContext, processRequest, refresh, service, setContextAttribute, setContextClass, setContextConfigLocation, setContextId, setContextInitializerClasses, setContextInitializers, setDispatchOptionsRequest, setDispatchTraceRequest, setNamespace, setPublishContext, setPublishEvents, setThreadContextInheritable

Methods inherited from class org.springframework.web.servlet.HttpServletBean

addRequiredProperty, createEnvironment, getEnvironment, getServletContext, getServletName, init, initBeanWrapper, setEnvironment

Methods inherited from class javax.servlet.http.HttpServlet

doHead, getLastModified, service

Methods inherited from class javax.servlet.GenericServlet

getInitParameter, getInitParameterNames, getServletConfig, getServletInfo, init, log, log

Methods inherited from class java.lang.Object

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

Field Detail

PREFIX_BYPASSED

public static final String PREFIX_BYPASSED

The prefix for the attribute added to the ServletContext when Spring MVC initialization is bypassed because a previous Event indicates the application has already failed. The MVC dispatcher's name is appended to this prefix, separated by a colon, to form the attribute.

Since:

3.0

See Also:

getBypassedAttributeName()

Constructor Detail

JohnsonDispatcherServlet

public JohnsonDispatcherServlet()

JohnsonDispatcherServlet

public JohnsonDispatcherServlet(org.springframework.web.context.WebApplicationContext webApplicationContext)

Method Detail

destroy

public void destroy()

Performs standard SpringMVC DispatcherServlet teardown and ensures any attributes added to the servlet context for this dispatcher are removed.

Specified by:

destroy in interface javax.servlet.Servlet

Overrides:

destroy in class org.springframework.web.servlet.FrameworkServlet

initWebApplicationContext

protected org.springframework.web.context.WebApplicationContext initWebApplicationContext()

Overrides the standard SpringMVC DispatcherServlet initialisation to make it Johnson-aware, allowing it to be automatically bypassed, when paired with a JohnsonContextLoaderListener, or add an Event if initialisation fails.

This implementation will never throw an exception. Unlike the base implementation, though, it may return null if initialisation is bypassed (due to the main WebApplicationContext being bypassed or failing to initialise) or if initialisation fails.

Overrides:

initWebApplicationContext in class org.springframework.web.servlet.FrameworkServlet

Returns:

the initialised context, or null if initialisation is bypassed or fails

createEvent

@Nonnull
protected Event createEvent(@Nonnull
                                     String defaultEventType,
                                     @Nonnull
                                     String defaultMessage,
                                     @Nonnull
                                     Throwable t)

May be overridden in derived classes to allow them to override the default event type or message based on application-specific understanding of the exception that was thrown.

For cases where derived classes are not able to offer a more specific event type or message, they are encouraged to fall back on the behaviour of this superclass method.

Parameters:

defaultEventType - the default event type to use if no more specific type is appropriate

defaultMessage - the default message to use if no more specific message is available

t - the exception thrown while attempting to initialise the WebApplicationContext

Returns:

the event to add to Johnson, which may not be null

getBypassedAttributeName

@Nonnull
protected String getBypassedAttributeName()

Allows derived classes to override the name of the attribute which is added to the ServletContext when this dispatcher is bypassed (whether due to the JohnsonContextLoaderListener being bypassed or due to the initialisation of the dispatcher failing).

The default attribute name is: "PREFIX_BYPASSED:getServletName()"

Returns:

the name for the bypassed context attribute