For this is example, 3 of the panes are empty. The fourth pane contains PSML References.
PSML References are used to include an entire PSML resource into another PSML resource. This is useful for defining groups of markup once, and then sharing that markup in one or more PSML resources. The reference path is called a PSML resource locator. In our example, we reference two shared group resources as the content of the fourth pane.
<portlets id="104"> <controller name="OneColumn"/> <metainfo> <title>Referenced Portlets</title> </metainfo> <reference path="group/apache/media-type/html/page/default"/> <reference path="group/Jetspeed/media-type/html/page/default"/> </portlets>
These two PSML resources are included with the Jetspeed distribution. In the first case, the locator specifies that it is a group resource, for the media type HTML, and the name of the resource page is default. Shared PSML resources are useful for defining common layout definitions that can be used by all users of the system.