org.springframework.web.servlet.handler
Class AbstractHandlerMapping

java.lang.Object
  extended by org.springframework.context.support.ApplicationObjectSupport
      extended by org.springframework.web.context.support.WebApplicationObjectSupport
          extended by org.springframework.web.servlet.handler.AbstractHandlerMapping
All Implemented Interfaces:
Aware, ApplicationContextAware, Ordered, ServletContextAware, HandlerMapping
Direct Known Subclasses:
AbstractUrlHandlerMapping

public abstract class AbstractHandlerMapping
extends WebApplicationObjectSupport
implements HandlerMapping, Ordered

Abstract base class for HandlerMapping implementations. Supports ordering, a default handler, and handler interceptors.

Note: This base class does not support exposure of the HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE. Support for this attribute is up to concrete subclasses, typically based on request URL mappings.

Since:
07.04.2003
Author:
Juergen Hoeller
See Also:
getHandlerInternal(javax.servlet.http.HttpServletRequest), setDefaultHandler(java.lang.Object), setInterceptors(java.lang.Object[]), HandlerInterceptor

Field Summary
 
Fields inherited from class org.springframework.context.support.ApplicationObjectSupport
logger
 
Fields inherited from interface org.springframework.web.servlet.HandlerMapping
BEST_MATCHING_PATTERN_ATTRIBUTE, INTROSPECT_TYPE_LEVEL_MAPPING, PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, URI_TEMPLATE_VARIABLES_ATTRIBUTE
 
Fields inherited from interface org.springframework.core.Ordered
HIGHEST_PRECEDENCE, LOWEST_PRECEDENCE
 
Constructor Summary
AbstractHandlerMapping()
           
 
Method Summary
protected  HandlerInterceptor adaptInterceptor(Object interceptor)
          Adapt the given interceptor object to the HandlerInterceptor interface.
protected  void extendInterceptors(List<Object> interceptors)
          Extension hook that subclasses can override to register additional interceptors, given the configured interceptors (see setInterceptors(java.lang.Object[])).
protected  HandlerInterceptor[] getAdaptedInterceptors()
          Return the adapted interceptors as HandlerInterceptor array.
 Object getDefaultHandler()
          Return the default handler for this handler mapping, or null if none.
 HandlerExecutionChain getHandler(HttpServletRequest request)
          Look up a handler for the given request, falling back to the default handler if no specific one is found.
protected  HandlerExecutionChain getHandlerExecutionChain(Object handler, HttpServletRequest request)
          Build a HandlerExecutionChain for the given handler, including applicable interceptors.
protected abstract  Object getHandlerInternal(HttpServletRequest request)
          Look up a handler for the given request, returning null if no specific one is found.
 int getOrder()
          Return the order value of this object, with a higher value meaning greater in terms of sorting.
protected  void initApplicationContext()
          Initializes the interceptors.
protected  void initInterceptors()
          Initialize the specified interceptors, adapting them where necessary.
 void setDefaultHandler(Object defaultHandler)
          Set the default handler for this handler mapping.
 void setInterceptors(Object[] interceptors)
          Set the interceptors to apply for all handlers mapped by this handler mapping.
 void setOrder(int order)
          Specify the order value for this HandlerMapping bean.
 
Methods inherited from class org.springframework.web.context.support.WebApplicationObjectSupport
getServletContext, getTempDir, getWebApplicationContext, initApplicationContext, initServletContext, isContextRequired, setServletContext
 
Methods inherited from class org.springframework.context.support.ApplicationObjectSupport
getApplicationContext, getMessageSourceAccessor, requiredContextClass, setApplicationContext
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

AbstractHandlerMapping

public AbstractHandlerMapping()
Method Detail

setOrder

public final void setOrder(int order)
Specify the order value for this HandlerMapping bean.

Default value is Integer.MAX_VALUE, meaning that it's non-ordered.

See Also:
Ordered.getOrder()

getOrder

public final int getOrder()
Description copied from interface: Ordered
Return the order value of this object, with a higher value meaning greater in terms of sorting.

Normally starting with 0, with Integer.MAX_VALUE indicating the greatest value. Same order values will result in arbitrary positions for the affected objects.

Higher values can be interpreted as lower priority. As a consequence, the object with the lowest value has highest priority (somewhat analogous to Servlet "load-on-startup" values).

Specified by:
getOrder in interface Ordered
Returns:
the order value

setDefaultHandler

public void setDefaultHandler(Object defaultHandler)
Set the default handler for this handler mapping. This handler will be returned if no specific mapping was found.

Default is null, indicating no default handler.


getDefaultHandler

public Object getDefaultHandler()
Return the default handler for this handler mapping, or null if none.


setInterceptors

public void setInterceptors(Object[] interceptors)
Set the interceptors to apply for all handlers mapped by this handler mapping.

Supported interceptor types are HandlerInterceptor and WebRequestInterceptor.

Parameters:
interceptors - array of handler interceptors, or null if none
See Also:
adaptInterceptor(java.lang.Object), HandlerInterceptor, WebRequestInterceptor

initApplicationContext

protected void initApplicationContext()
                               throws BeansException
Initializes the interceptors.

Overrides:
initApplicationContext in class ApplicationObjectSupport
Throws:
ApplicationContextException - in case of initialization errors
BeansException - if thrown by ApplicationContext methods
See Also:
extendInterceptors(java.util.List), initInterceptors()

extendInterceptors

protected void extendInterceptors(List<Object> interceptors)
Extension hook that subclasses can override to register additional interceptors, given the configured interceptors (see setInterceptors(java.lang.Object[])).

Will be invoked before initInterceptors() adapts the specified interceptors into HandlerInterceptor instances.

The default implementation is empty.

Parameters:
interceptors - the configured interceptor List (never null), allowing to add further interceptors before as well as after the existing interceptors

initInterceptors

protected void initInterceptors()
Initialize the specified interceptors, adapting them where necessary.

See Also:
setInterceptors(java.lang.Object[]), adaptInterceptor(java.lang.Object)

adaptInterceptor

protected HandlerInterceptor adaptInterceptor(Object interceptor)
Adapt the given interceptor object to the HandlerInterceptor interface.

Supported interceptor types are HandlerInterceptor and WebRequestInterceptor. Each given WebRequestInterceptor will be wrapped in a WebRequestHandlerInterceptorAdapter. Can be overridden in subclasses.

Parameters:
interceptor - the specified interceptor object
Returns:
the interceptor wrapped as HandlerInterceptor
See Also:
HandlerInterceptor, WebRequestInterceptor, WebRequestHandlerInterceptorAdapter

getAdaptedInterceptors

protected final HandlerInterceptor[] getAdaptedInterceptors()
Return the adapted interceptors as HandlerInterceptor array.

Returns:
the array of HandlerInterceptors, or null if none

getHandler

public final HandlerExecutionChain getHandler(HttpServletRequest request)
                                       throws Exception
Look up a handler for the given request, falling back to the default handler if no specific one is found.

Specified by:
getHandler in interface HandlerMapping
Parameters:
request - current HTTP request
Returns:
the corresponding handler instance, or the default handler
Throws:
Exception - if there is an internal error
See Also:
getHandlerInternal(javax.servlet.http.HttpServletRequest)

getHandlerInternal

protected abstract Object getHandlerInternal(HttpServletRequest request)
                                      throws Exception
Look up a handler for the given request, returning null if no specific one is found. This method is called by getHandler(javax.servlet.http.HttpServletRequest); a null return value will lead to the default handler, if one is set.

Note: This method may also return a pre-built HandlerExecutionChain, combining a handler object with dynamically determined interceptors. Statically specified interceptors will get merged into such an existing chain.

Parameters:
request - current HTTP request
Returns:
the corresponding handler instance, or null if none found
Throws:
Exception - if there is an internal error

getHandlerExecutionChain

protected HandlerExecutionChain getHandlerExecutionChain(Object handler,
                                                         HttpServletRequest request)
Build a HandlerExecutionChain for the given handler, including applicable interceptors.

The default implementation simply builds a standard HandlerExecutionChain with the given handler and this handler mapping's common interceptors. Subclasses may override this in order to extend/rearrange the list of interceptors.

NOTE: The passed-in handler object may be a raw handler or a pre-built HandlerExecutionChain. This method should handle those two cases explicitly, either building a new HandlerExecutionChain or extending the existing chain.

For simply adding an interceptor, consider calling super.getHandlerExecutionChain and invoking HandlerExecutionChain.addInterceptor(org.springframework.web.servlet.HandlerInterceptor) on the returned chain object.

Parameters:
handler - the resolved handler instance (never null)
request - current HTTP request
Returns:
the HandlerExecutionChain (never null)
See Also:
getAdaptedInterceptors()