org.springframework.web.servlet.handler

## Class AbstractHandlerMethodMapping<T>

- java.lang.Object
- - org.springframework.context.support.ApplicationObjectSupport
  - - org.springframework.web.context.support.WebApplicationObjectSupport
    - - org.springframework.web.servlet.handler.AbstractHandlerMapping
      - - org.springframework.web.servlet.handler.AbstractHandlerMethodMapping<T>

- Type Parameters:
    `T` - The mapping for a `HandlerMethod` containing the conditions needed to match the handler method to incoming request.
  All Implemented Interfaces:
    Aware, InitializingBean, ApplicationContextAware, Ordered, ServletContextAware, HandlerMapping
  Direct Known Subclasses:
    RequestMappingInfoHandlerMapping

      public abstract class AbstractHandlerMethodMapping<T>
      extends AbstractHandlerMapping
      implements InitializingBean

  Abstract base class for `HandlerMapping` implementations that define a mapping between a request and a `HandlerMethod`.

  For each registered handler method, a unique mapping is maintained with subclasses defining the details of the mapping type `<T>`.

  Since:
    3.1
  Author:
    Arjen Poutsma, Rossen Stoyanchev

- - ### 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, MATRIX_VARIABLES_ATTRIBUTE, PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, PRODUCIBLE_MEDIA_TYPES_ATTRIBUTE, URI_TEMPLATE_VARIABLES_ATTRIBUTE`

    - ### Fields inherited from interface org.springframework.core.Ordered

      `HIGHEST_PRECEDENCE, LOWEST_PRECEDENCE`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `AbstractHandlerMethodMapping()`

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `afterPropertiesSet()` Detects handler methods at initialization.
    `protected HandlerMethod` | `createHandlerMethod(Object handler, Method method)` Create the HandlerMethod instance.
    `protected void` | `detectHandlerMethods(Object handler)` Look for handler methods in a handler.
    `protected HandlerMethod` | `getHandlerInternal(HttpServletRequest request)` Look up a handler method for the given request.
    `Map<T,HandlerMethod>` | `getHandlerMethods()` Return a map with all handler methods and their mappings.
    `protected abstract Comparator<T>` | `getMappingComparator(HttpServletRequest request)` Return a comparator for sorting matching mappings.
    `protected abstract T` | `getMappingForMethod(Method method, Class<?> handlerType)` Provide the mapping for a handler method.
    `protected abstract Set<String>` | `getMappingPathPatterns(T mapping)` Extract and return the URL paths contained in a mapping.
    `protected abstract T` | `getMatchingMapping(T mapping, HttpServletRequest request)` Check if a mapping matches the current request and return a (potentially new) mapping with conditions relevant to the current request.
    `protected void` | `handleMatch(T mapping, String lookupPath, HttpServletRequest request)` Invoked when a matching mapping is found.
    `protected HandlerMethod` | `handleNoMatch(Set<T> mappings, String lookupPath, HttpServletRequest request)` Invoked when no matching mapping is not found.
    `protected void` | `handlerMethodsInitialized(Map<T,HandlerMethod> handlerMethods)` Invoked after all handler methods have been detected.
    `protected void` | `initHandlerMethods()` Scan beans in the ApplicationContext, detect and register handler methods.
    `protected abstract boolean` | `isHandler(Class<?> beanType)` Whether the given type is a handler with handler methods.
    `protected HandlerMethod` | `lookupHandlerMethod(String lookupPath, HttpServletRequest request)` Look up the best-matching handler method for the current request.
    `protected void` | `registerHandlerMethod(Object handler, Method method, T mapping)` Register a handler method and its unique mapping.
    `void` | `setDetectHandlerMethodsInAncestorContexts(boolean detectHandlerMethodsInAncestorContexts)` Whether to detect handler methods in beans in ancestor ApplicationContexts.

    - ### Methods inherited from class org.springframework.web.servlet.handler.AbstractHandlerMapping

      `adaptInterceptor, detectMappedInterceptors, extendInterceptors, getAdaptedInterceptors, getDefaultHandler, getHandler, getHandlerExecutionChain, getMappedInterceptors, getOrder, getPathMatcher, getUrlPathHelper, initApplicationContext, initInterceptors, setAlwaysUseFullPath, setDefaultHandler, setInterceptors, setOrder, setPathMatcher, setRemoveSemicolonContent, setUrlDecode, setUrlPathHelper`

    - ### 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

    - #### AbstractHandlerMethodMapping

          public AbstractHandlerMethodMapping()

  - ### Method Detail

    - #### setDetectHandlerMethodsInAncestorContexts

          public void setDetectHandlerMethodsInAncestorContexts(boolean detectHandlerMethodsInAncestorContexts)

      Whether to detect handler methods in beans in ancestor ApplicationContexts.

      Default is "false": Only beans in the current ApplicationContext are considered, i.e. only in the context that this HandlerMapping itself is defined in (typically the current DispatcherServlet's context).

      Switch this flag on to detect handler beans in ancestor contexts (typically the Spring root WebApplicationContext) as well.

    - #### getHandlerMethods

          public Map<T,HandlerMethod> getHandlerMethods()

      Return a map with all handler methods and their mappings.

    - #### afterPropertiesSet

          public void afterPropertiesSet()

      Detects handler methods at initialization.
      Specified by:
        `afterPropertiesSet` in interface `InitializingBean`

    - #### initHandlerMethods

          protected void initHandlerMethods()

      Scan beans in the ApplicationContext, detect and register handler methods.
      See Also:
        `isHandler(Class)`, `getMappingForMethod(Method, Class)`, `handlerMethodsInitialized(Map)`

    - #### isHandler

          protected abstract boolean isHandler(Class<?> beanType)

      Whether the given type is a handler with handler methods.
      Parameters:
        `beanType` - the type of the bean being checked
      Returns:
        "true" if this a handler type, "false" otherwise.

    - #### handlerMethodsInitialized

          protected void handlerMethodsInitialized(Map<T,HandlerMethod> handlerMethods)

      Invoked after all handler methods have been detected.
      Parameters:
        `handlerMethods` - a read-only map with handler methods and mappings.

    - #### detectHandlerMethods

          protected void detectHandlerMethods(Object handler)

      Look for handler methods in a handler.
      Parameters:
        `handler` - the bean name of a handler or a handler instance

    - #### getMappingForMethod

          protected abstract T getMappingForMethod(Method method,
                              Class<?> handlerType)

      Provide the mapping for a handler method. A method for which no mapping can be provided is not a handler method.
      Parameters:
        `method` - the method to provide a mapping for
        `handlerType` - the handler type, possibly a sub-type of the method's declaring class
      Returns:
        the mapping, or `null` if the method is not mapped

    - #### registerHandlerMethod

          protected void registerHandlerMethod(Object handler,
                                   Method method,
                                   T mapping)

      Register a handler method and its unique mapping.
      Parameters:
        `handler` - the bean name of the handler or the handler instance
        `method` - the method to register
        `mapping` - the mapping conditions associated with the handler method
      Throws:
        `IllegalStateException` - if another method was already registered under the same mapping

    - #### createHandlerMethod

          protected HandlerMethod createHandlerMethod(Object handler,
                                          Method method)

      Create the HandlerMethod instance.
      Parameters:
        `handler` - either a bean name or an actual handler instance
        `method` - the target method
      Returns:
        the created HandlerMethod

    - #### getMappingPathPatterns

          protected abstract Set<String> getMappingPathPatterns(T mapping)

      Extract and return the URL paths contained in a mapping.

    - #### getHandlerInternal

          protected HandlerMethod getHandlerInternal(HttpServletRequest request)
                                              throws Exception

      Look up a handler method for the given request.
      Specified by:
        `getHandlerInternal` in class `AbstractHandlerMapping`
      Parameters:
        `request` - current HTTP request
      Returns:
        the corresponding handler instance, or `null` if none found
      Throws:
        `Exception` - if there is an internal error

    - #### lookupHandlerMethod

          protected HandlerMethod lookupHandlerMethod(String lookupPath,
                                          HttpServletRequest request)
                                               throws Exception

      Look up the best-matching handler method for the current request. If multiple matches are found, the best match is selected.
      Parameters:
        `lookupPath` - mapping lookup path within the current servlet mapping
        `request` - the current request
      Returns:
        the best-matching handler method, or `null` if no match
      Throws:
        `Exception`
      See Also:
        `handleMatch(Object, String, HttpServletRequest)`, `handleNoMatch(Set, String, HttpServletRequest)`

    - #### getMatchingMapping

          protected abstract T getMatchingMapping(T mapping,
                             HttpServletRequest request)

      Check if a mapping matches the current request and return a (potentially new) mapping with conditions relevant to the current request.
      Parameters:
        `mapping` - the mapping to get a match for
        `request` - the current HTTP servlet request
      Returns:
        the match, or `null` if the mapping doesn't match

    - #### getMappingComparator

          protected abstract Comparator<T> getMappingComparator(HttpServletRequest request)

      Return a comparator for sorting matching mappings. The returned comparator should sort 'better' matches higher.
      Parameters:
        `request` - the current request
      Returns:
        the comparator, never `null`

    - #### handleMatch

          protected void handleMatch(T mapping,
                         String lookupPath,
                         HttpServletRequest request)

      Invoked when a matching mapping is found.
      Parameters:
        `mapping` - the matching mapping
        `lookupPath` - mapping lookup path within the current servlet mapping
        `request` - the current request

    - #### handleNoMatch

          protected HandlerMethod handleNoMatch(Set<T> mappings,
                                    String lookupPath,
                                    HttpServletRequest request)
                                         throws Exception

      Invoked when no matching mapping is not found.
      Parameters:
        `mappings` - all registered mappings
        `lookupPath` - mapping lookup path within the current servlet mapping
        `request` - the current request
      Throws:
        `ServletException` - in case of errors
        `Exception`