Package org.opencms.loader

Interface I_CmsResourceLoader

All Superinterfaces:
I_CmsConfigurationParameterHandler
All Known Implementing Classes:
CmsDumpLoader, CmsImageLoader, CmsJspLoader, CmsMacroFormatterLoader, CmsPointerLoader, CmsRedirectLoader, CmsSeoFileLoader, CmsXmlContainerPageLoader, CmsXmlContentLoader, CmsXmlPageLoader
public interface I_CmsResourceLoader extends I_CmsConfigurationParameterHandler
This interface describes a resource loader for OpenCms, a class that can load a resource from the VFS, process it's contents and deliver the result to the user.

The I_CmsResourceLoader operates with Request and Response in much the same way as a standard Java web application.

This interface uses a standard servlet HttpServletRequestWrapper / HttpServletResponseWrapper that provide access to a special implementation of the RequestDispatcher. The handling of the output written to the response is done by this dispatcher. The results are then passed back to OpenCms which will deliver them to the requesting user.

Since:
6.0.0
See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final String
    PARAMETER_ELEMENT
    Request parameter to force element selection.

    Fields inherited from interface org.opencms.configuration.I_CmsConfigurationParameterHandler

    ADD_PARAMETER_METHOD, INIT_CONFIGURATION_METHOD

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    destroy()
    Destroys this ResourceLoder.
    byte[]
    dump(CmsObject cms, CmsResource resource, String element, Locale locale, javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse res)
    Dumps the processed content of the the requested file (and it's sub-elements) to a byte array.
    byte[]
    export(CmsObject cms, CmsResource resource, javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse res)
    Static exports the contents of the requested file and it's sub-elements.
    int
    getLoaderId()
    Returns the id of the ResourceLoader.
    String
    getResourceLoaderInfo()
    Returns a String describing the ResourceLoader.
    boolean
    isStaticExportEnabled()
    Signals if the loader implementation supports static export of resources.
    boolean
    isStaticExportProcessable()
    Signals if the loader implementation requires processing during static export of resources.
    boolean
    isUsableForTemplates()
    Signals if the loader implementation is usable for creating templates.
    boolean
    isUsingUriWhenLoadingTemplate()
    Signals if a loader that supports templates must be invoked on the template URI or the resource URI.
    void
    load(CmsObject cms, CmsResource resource, javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse res)
    Basic top-page processing method for a I_CmsResourceLoader, this method is called if the page is called as a sub-element on a page not already loaded with a I_CmsResourceLoader.
    void
    service(CmsObject cms, CmsResource resource, javax.servlet.ServletRequest req, javax.servlet.ServletResponse res)
    Does the job of including the requested resource, this method is called directly if the element is called as a sub-element from another I_CmsResourceLoader.

    Methods inherited from interface org.opencms.configuration.I_CmsConfigurationParameterHandler

    addConfigurationParameter, getConfiguration, initConfiguration

  • Field Details

  • Method Details

    • destroy

      void destroy()
      Destroys this ResourceLoder.

    • dump

      byte[] dump(CmsObject cms, CmsResource resource, String element, Locale locale, javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse res) throws javax.servlet.ServletException, IOException, CmsException
      Dumps the processed content of the the requested file (and it's sub-elements) to a byte array.

      Dumping the content is like calling "load" where the result is not written to the response stream, but to the returned byte array. Dumping is different from an export because the export might actually require that the content is handled or modified in a special way, or set special http headers.

      Moreover, if the page type is template based, calling "dump" will not trigger the template but directly deliver the contents from the selected element.

      Parameters:
      cms - used to access the OpenCms VFS
      resource - the requested resource in the VFS
      element - the element in the file to display
      locale - the locale to display
      req - the servlet request
      res - the servlet response
      Returns:
      the content of the processed file
      Throws:
      javax.servlet.ServletException - might be thrown by the servlet environment
      IOException - might be thrown by the servlet environment
      CmsException - in case of errors accessing OpenCms functions

    • export

      byte[] export(CmsObject cms, CmsResource resource, javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse res) throws javax.servlet.ServletException, IOException, CmsException
      Static exports the contents of the requested file and it's sub-elements.

      During static export, the resource content may be written to 2 streams: The export stream, and the http response output stream. Which stream is actually used depends whether the export is in "on demand" or "after publish" mode. In "on demand" mode, the resource needs to be written both to the response stream and to the file stream. In "after publish" mode, it's usually only written to the file stream, but sometimes it's required to write to the response stream as well.

      Parameters:
      cms - the initialized CmsObject which provides user permissions
      resource - the requested OpenCms VFS resource
      req - the servlet request
      res - the servlet response
      Returns:
      the contents to export, or null if no export is required
      Throws:
      javax.servlet.ServletException - might be thrown in the process of including the sub element
      IOException - might be thrown in the process of including the sub element
      CmsException - in case something goes wrong

    • getLoaderId

      int getLoaderId()
      Returns the id of the ResourceLoader.

      Returns:
      the id of the ResourceLoader

    • getResourceLoaderInfo

      String getResourceLoaderInfo()
      Returns a String describing the ResourceLoader.

      Returns:
      a String describing the ResourceLoader

    • isStaticExportEnabled

      boolean isStaticExportEnabled()
      Signals if the loader implementation supports static export of resources.

      Returns:
      true if static export is supported, false otherwise

    • isStaticExportProcessable

      boolean isStaticExportProcessable()
      Signals if the loader implementation requires processing during static export of resources.

      Returns:
      true if static export processing is required, false otherwise

    • isUsableForTemplates

      boolean isUsableForTemplates()
      Signals if the loader implementation is usable for creating templates.

      Returns:
      true if the loader implementation is usable for creating templates, false otherwise

    • isUsingUriWhenLoadingTemplate

      boolean isUsingUriWhenLoadingTemplate()
      Signals if a loader that supports templates must be invoked on the template URI or the resource URI.

      Returns:
      true if the resource URI is to be used, false if the template URI is to be used

    • load

      void load(CmsObject cms, CmsResource resource, javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse res) throws javax.servlet.ServletException, IOException, CmsException
      Basic top-page processing method for a I_CmsResourceLoader, this method is called if the page is called as a sub-element on a page not already loaded with a I_CmsResourceLoader.

      Parameters:
      cms - the initialized CmsObject which provides user permissions
      resource - the requested OpenCms VFS resource
      req - the servlet request
      res - the servlet response
      Throws:
      javax.servlet.ServletException - might be thrown by the servlet environment
      IOException - might be thrown by the servlet environment
      CmsException - in case of errors accessing OpenCms functions
      See Also:

    • service

      void service(CmsObject cms, CmsResource resource, javax.servlet.ServletRequest req, javax.servlet.ServletResponse res) throws javax.servlet.ServletException, IOException, CmsException
      Does the job of including the requested resource, this method is called directly if the element is called as a sub-element from another I_CmsResourceLoader.

      Parameters:
      cms - used to access the OpenCms VFS
      resource - the requested resource in the VFS
      req - the servlet request
      res - the servlet response
      Throws:
      javax.servlet.ServletException - might be thrown by the servlet environment
      IOException - might be thrown by the servlet environment
      CmsException - in case of errors accessing OpenCms functions
      See Also: