diff -r 005d27918b57 -r f4608ad6c947 src/java/de/uapcore/lightpit/Constants.java
--- a/src/java/de/uapcore/lightpit/Constants.java	Sat Dec 23 17:28:19 2017 +0100
+++ b/src/java/de/uapcore/lightpit/Constants.java	Tue Dec 26 17:36:47 2017 +0100
@@ -31,11 +31,23 @@
 import static de.uapcore.lightpit.Functions.fqn;
 
 /**
- * Contains all constants used by the this application.
+ * Contains all non-local scope constants used by the this application.
+ * 
+ * Constants with (class) local scope are defined in their respective classes.
  */
 public final class Constants {
     public static final String JSP_PATH_PREFIX = "/WEB-INF/jsp/";
     
+    public static final String JSPF_PATH_PREFIX = "/WEB-INF/jspf/";
+    
+    public static final String DYN_FRAGMENT_PATH_PREFIX = "/WEB-INF/dynamic_fragments/";
+    
+    
+    /**
+     * Name for the context parameter specifying the available languages.
+     */
+    public static final String CTX_ATTR_LANGUAGES = "available-languages";
+    
     /**
      * Key for the request attribute containing the class name of the currently dispatching module.
      */
@@ -55,6 +67,22 @@
      * Key for the request attribute containing the full path information (servlet path + path info).
      */
     public static final String REQ_ATTR_PATH = fqn(AbstractLightPITServlet.class, "path");
+
+    /**
+     * Key for the name of the fragment which should be rendered.
+     */    
+    public static final String REQ_ATTR_FRAGMENT = fqn(AbstractLightPITServlet.class, "fragment");
+    
+    /**
+     * Key for the name of the additional stylesheet used by a module.
+     */    
+    public static final String REQ_ATTR_STYLESHEET = fqn(AbstractLightPITServlet.class, "extraCss");
+    
+    
+    /**
+     * Key for the current language selection within the session.
+     */
+    public static final String SESSION_ATTR_LANGUAGE = fqn(AbstractLightPITServlet.class, "language");
     
     /**
      * This class is not instantiatable.