Class WebContentGenerator

java.lang.Object
org.springframework.context.support.ApplicationObjectSupport
org.springframework.web.context.support.WebApplicationObjectSupport
org.springframework.web.servlet.support.WebContentGenerator
All Implemented Interfaces:
Aware, ApplicationContextAware, ServletContextAware
Direct Known Subclasses:
AbstractController, AbstractHandlerMethodAdapter, ResourceHttpRequestHandler, WebContentInterceptor
public abstract class WebContentGenerator extends WebApplicationObjectSupport
Convenient superclass for any kind of web content generator, like AbstractController and WebContentInterceptor. Can also be used for custom handlers that have their own HandlerAdapter.

Supports HTTP cache control options. The usage of corresponding HTTP headers can be controlled via the "cacheSeconds" and "cacheControl" properties.

Author:
Rod Johnson, Juergen Hoeller, Brian Clozel, Rossen Stoyanchev
See Also:

  • Field Details

  • Constructor Details

    • WebContentGenerator

      public WebContentGenerator()
      Create a new WebContentGenerator which supports HTTP methods GET, HEAD and POST by default.

    • WebContentGenerator

      public WebContentGenerator(boolean restrictDefaultSupportedMethods)
      Create a new WebContentGenerator.
      Parameters:
      restrictDefaultSupportedMethods - true if this generator should support HTTP methods GET, HEAD and POST by default, or false if it should be unrestricted

    • WebContentGenerator

      public WebContentGenerator(String... supportedMethods)
      Create a new WebContentGenerator.
      Parameters:
      supportedMethods - the supported HTTP methods for this content generator

  • Method Details

    • setSupportedMethods

      public final void setSupportedMethods(String @Nullable ... methods)
      Set the HTTP methods that this content generator should support.

      Default is GET, HEAD and POST for simple form controller types; unrestricted for general controllers and interceptors.

    • getSupportedMethods

      public final String @Nullable [] getSupportedMethods()
      Return the HTTP methods that this content generator supports.

    • getAllowHeader

      protected @Nullable String getAllowHeader()
      Return the "Allow" header value to use in response to an HTTP OPTIONS request based on the configured supported methods also automatically adding "OPTIONS" to the list even if not present as a supported method. This means subclasses don't have to explicitly list "OPTIONS" as a supported method as long as HTTP OPTIONS requests are handled before making a call to checkRequest(HttpServletRequest).
      Since:
      4.3

    • setRequireSession

      public final void setRequireSession(boolean requireSession)
      Set whether a session should be required to handle requests.

    • isRequireSession

      public final boolean isRequireSession()
      Return whether a session is required to handle requests.

    • setCacheControl

      public final void setCacheControl(@Nullable CacheControl cacheControl)
      Set the CacheControl instance to build the Cache-Control HTTP response header.
      Since:
      4.2

    • getCacheControl

      public final @Nullable CacheControl getCacheControl()
      Get the CacheControl instance that builds the Cache-Control HTTP response header.
      Since:
      4.2

    • setCacheSeconds

      public final void setCacheSeconds(int seconds)
      Cache content for the given number of seconds, by writing cache-related HTTP headers to the response:
      • seconds == -1 (default value): no generation cache-related headers
      • seconds == 0: "Cache-Control: no-store" will prevent caching
      • seconds > 0: "Cache-Control: max-age=seconds" will ask to cache content

      For more specific needs, a custom CacheControl should be used.

      See Also:

    • getCacheSeconds

      public final int getCacheSeconds()
      Return the number of seconds that content is cached.

    • setVaryByRequestHeaders

      public final void setVaryByRequestHeaders(String @Nullable ... varyByRequestHeaders)
      Configure one or more request header names (for example, "Accept-Language") to add to the "Vary" response header to inform clients that the response is subject to content negotiation and variances based on the value of the given request headers. The configured request header names are added only if not already present in the response "Vary" header.
      Parameters:
      varyByRequestHeaders - one or more request header names
      Since:
      4.3

    • getVaryByRequestHeaders

      public final String @Nullable [] getVaryByRequestHeaders()
      Return the configured request header names for the "Vary" response header.
      Since:
      4.3

    • checkRequest

      protected final void checkRequest(HttpServletRequest request) throws ServletException
      Check the given request for supported methods and a required session, if any.
      Parameters:
      request - current HTTP request
      Throws:
      ServletException - if the request cannot be handled because a check failed
      Since:
      4.2

    • prepareResponse

      protected final void prepareResponse(HttpServletResponse response)
      Prepare the given response according to the settings of this generator. Applies the number of cache seconds specified for this generator.
      Parameters:
      response - current HTTP response
      Since:
      4.2

    • applyCacheControl

      protected final void applyCacheControl(HttpServletResponse response, CacheControl cacheControl)
      Set the HTTP Cache-Control header according to the given settings.
      Parameters:
      response - current HTTP response
      cacheControl - the pre-configured cache control settings
      Since:
      4.2

    • applyCacheSeconds

      protected final void applyCacheSeconds(HttpServletResponse response, int cacheSeconds)
      Apply the given cache seconds and generate corresponding HTTP headers, i.e. allow caching for the given number of seconds in case of a positive value, prevent caching if given a 0 value, do nothing else. Does not tell the browser to revalidate the resource.
      Parameters:
      response - current HTTP response
      cacheSeconds - positive number of seconds into the future that the response should be cacheable for, 0 to prevent caching