Interface View

All Known Subinterfaces:
FragmentsRendering, SmartView
All Known Implementing Classes:
AbstractAtomFeedView, AbstractFeedView, AbstractJackson2View, AbstractJacksonView, AbstractPdfStamperView, AbstractPdfView, AbstractRssFeedView, AbstractTemplateView, AbstractUrlBasedView, AbstractView, AbstractXlsView, AbstractXlsxStreamingView, AbstractXlsxView, FreeMarkerView, GroovyMarkupView, InternalResourceView, JacksonJsonView, JacksonXmlView, JstlView, MappingJackson2JsonView, MappingJackson2XmlView, MarshallingView, RedirectView, ScriptTemplateView, XsltView
public interface View
MVC View for a web interaction. Implementations are responsible for rendering content, and exposing the model. A single view exposes multiple model attributes.

This class and the MVC approach associated with it is discussed in Chapter 12 of Expert One-On-One J2EE Design and Development by Rod Johnson (Wrox, 2002).

View implementations may differ widely. An obvious implementation would be JSP-based. Other implementations might be XSLT-based, or use an HTML generation library. This interface is designed to avoid restricting the range of possible implementations.

Views should be beans. They are likely to be instantiated as beans by a ViewResolver. As this interface is stateless, view implementations should be thread-safe.

Author:
Rod Johnson, Arjen Poutsma, Rossen Stoyanchev
See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final String
    PATH_VARIABLES
    Name of the HttpServletRequest attribute that contains a Map with path variables.
    static final String
    RESPONSE_STATUS_ATTRIBUTE
    Name of the HttpServletRequest attribute that contains the response status code.
    static final String
    SELECTED_CONTENT_TYPE
    The MediaType selected during content negotiation, which may be more specific than the one the View is configured with.

  • Method Summary

    Modifier and Type
    Method
    Description
    default @Nullable String
    getContentType()
    Return the content type of the view, if predetermined.
    void
    render(@Nullable Map<String,?> model, jakarta.servlet.http.HttpServletRequest request, jakarta.servlet.http.HttpServletResponse response)
    Render the view given the specified model.

  • Field Details

    • RESPONSE_STATUS_ATTRIBUTE

      static final String RESPONSE_STATUS_ATTRIBUTE
      Name of the HttpServletRequest attribute that contains the response status code.

      Note: This attribute is not required to be supported by all View implementations.

      Since:
      3.0

    • PATH_VARIABLES

      static final String PATH_VARIABLES
      Name of the HttpServletRequest attribute that contains a Map with path variables. The map consists of String-based URI template variable names as keys and their corresponding Object-based values -- extracted from segments of the URL and type converted.

      Note: This attribute is not required to be supported by all View implementations.

      Since:
      3.1

    • SELECTED_CONTENT_TYPE

      static final String SELECTED_CONTENT_TYPE
      The MediaType selected during content negotiation, which may be more specific than the one the View is configured with. For example: "application/vnd.example-v1+xml" vs "application/*+xml".
      Since:
      3.2

  • Method Details

    • getContentType

      default @Nullable String getContentType()
      Return the content type of the view, if predetermined.

      Can be used to check the view's content type upfront, i.e. before an actual rendering attempt.

      Returns:
      the content type String (optionally including a character set), or null if not predetermined

    • render

      void render(@Nullable Map<String,?> model, jakarta.servlet.http.HttpServletRequest request, jakarta.servlet.http.HttpServletResponse response) throws Exception
      Render the view given the specified model.

      The first step will be preparing the request: In the JSP case, this would mean setting model objects as request attributes. The second step will be the actual rendering of the view, for example including the JSP via a RequestDispatcher.

      Parameters:
      model - a Map with name Strings as keys and corresponding model objects as values (Map can also be null in case of empty model)
      request - current HTTP request
      response - he HTTP response we are building
      Throws:
      Exception - if rendering failed