The PortletRegistry is a central store where Jetspeed can obtain further information about a given Portlet.

The Registry is organized like a flat list of portlets (identified in the markup but the entry element. All Portlets within the Registry must have a unique name.

The portlets are described in the registry by an Entry description. These entries may be of three distinct types:

instance - This is the basic entry type. An instance entry should provide all the necessary informations to instanciate the portlet (at least the classname). This type of entry is instanciated as is by the Jetspeed engine.

abstract - An abstract entry is a entry which can't be instanciated directly because it misses some required information. It acts as a portlet template, useful for defining common properties for a group of related portlets. This type of entry is never instanciated by Jetspeed.

ref - The ref entry is an entry that define a new entry based on some other entry definition, thus the ref entry definition must reference another registry entry which may be of any type, even other ref entries. The engine will cascade all refs until it finds either an abstract or instance entry. It will then override all the parameters found in the abstract or instance definitions by those found in the ref(s) definition and try to instanciate this portlet.

Whereas the registry describes all the Portlets in a single file, the markup uses one different file per registered user, thus providing customizability of the interface. With the new profiling service, users can have multiple markup files.

A default site description is used for anonymous access

The site markup uses 4 main type of elements which correpsond directly to layout classes.

Entry - Entries describe Portlet elements, just as in the registry markup. However, in the site markup, all entries are of type ref and can't define some basic properties (such as classname or url) for security and performance reasons. These entries may however define some additional properties not available in the registry such as skin and layout properties.

Portlets - Portlets describe a group of Portlet elements (PortletSet). Such groups are useful for setting common layout and presentation properties for the contained portlets. Each portlets may contain either entry elements or nested portlets.

Controller - The contoller element describes the PortletController associated with a given PortletSet. The PortletController implements a layout strategy for the portlets contained in the PortletSet.

Control - The control element which can be found in portlets or entry elements describes the PortletControl associated with object. The PortletControl may provide additionnal functionalities to a portlet and may also add some graphical decorations around the portlet content.

In PSML, all properties defined for an element are local to this element, except for the skin properties which are inherited ijn the component hierarchy.