Package org.apache.velocity.tools.view

Class IncludeTool

  • Direct Known Subclasses:
    MultiViewsTool
    @DefaultKey("include")
@InvalidScope("application")
public class IncludeTool
extends Object
    Allows for transparent content negotiation in a manner mimicking Apache httpd's MultiViews.

    Reads the default language out of the ViewToolContext as org.apache.velocity.tools.view.i18n.defaultLanguage. See find(String, String), find(String, Locale) and exists(String) for usage.

    This is the successor to the MultiViewsTool in VelocityTools 1.x. Please note that it does NOT do the actual #include or #parse for you, but is merely to aid in include content negotiation.

    Since:
    VelocityTools 2.0
    Version:
    $Id$
    Author:
    Daniel Rall, Nathan Bubna

    • Field Detail

      • DEFAULT_LANGUAGE_KEY

        protected static final String DEFAULT_LANGUAGE_KEY
        The key used to search initialization, context, and JVM parameters for the default language to use.
        See Also:
        Constant Field Values

      • defaultLanguage

        protected String defaultLanguage
        The two character abbreviation for the request's default language.

      • engine

        protected org.apache.velocity.app.VelocityEngine engine

    • Constructor Detail

      • IncludeTool

        public IncludeTool()

    • Method Detail

      • configure

        public void configure​(Map params)
        Extracts the default language from the specified ViewContext, looking first at the Velocity context, then the servlet context, then lastly at the JVM default. This "narrow scope to wide scope" pattern makes it easy to setup language overrides at different levels within your application.
        Parameters:
        params - the Map of configuration parameters
        Throws:
        IllegalArgumentException - if the param is not a ViewContext

      • find

        public String find​(String name,
                   String language)

        Finds the a localized version of the requested Velocity resource (such as a file or template) which is most appropriate for the locale of the current request. Use in conjuction with Apache httpd's MultiViews, or by itself.

        Usage from a template would be something like the following: 

         #parse( $include.find('header.vm', 'en') )
 #include( $include.find('my_page.html', 'en') )
 #parse( $include.find('footer.vm', 'en') )
        You might also wrap this method using another pull/view tool which does internationalization/localization/content negation for a single point of access.

        Parameters:
        name - The unlocalized name of the file to find.
        language - The language to find localized context for.
        Returns:
        The localized file name, or name if it is not localizable.

      • exists

        public boolean exists​(String name)

        Checks to see whether a #parse-able template or #include-able resource exists under the specified name/path.

        Usage from a template would be something like the following: 

         #if( $include.exists('header.vm') )
   #parse( 'header.vm' )
 #end
        See Also:
        VelocityEngine.resourceExists(java.lang.String)

      • exists

        public boolean exists​(String name,
                      String language)
        Checks to see whether a localized version of the named template exists for the specified language.
        See Also:
        exists(String)