A portlet is a Java technology based web component, managed by a portlet container, that processes requests and generates dynamic content. Portlets provide a presentation layer to Information Systems.
Portlets generate fragments of markup (e.g. HTML, XHTML, WML). A portal combines markup fragments generated by different portlets into a portal page.
A portlet container manages the lifecyle of portlets. It also provides the required runtime environment.
Portlets are bundled in Portlet Applications as web applications using the WAR file format. A portlet application consists of two deployment descriptors: one to specify the web application resources (web.xml) and one to specify the portlet resources (portlet.xml).
Click here for an example of a portlet resources deployment descriptor (portlet.xml).
Interface | Description |
---|---|
ActionRequest |
The
ActionRequest represents the request sent to the portlet
to handle an action. |
ActionResponse |
The
ActionResponse interface represents the portlet
response to an action request. |
PortalContext |
The
PortalContext interface gives the portlet
the ability to retrieve information about the portal calling this portlet. |
Portlet |
The
Portlet interface is used by the portlet container to
invoke the portlets. |
PortletConfig |
The
PortletConfig interface provides the portlet with
its configuration. |
PortletContext |
The
PortletContext interface defines a portlet view
of the portlet container. |
PortletPreferences |
The
PortletPreferences interface allows the portlet to store
configuration data. |
PortletRequest |
The
PortletRequest defines the base interface to provide client
request information to a portlet. |
PortletRequestDispatcher |
The
PortletRequestDispatcher interface
defines an object that receives requests from the client
and sends them to the specified resources (such as a servlet,
HTML file, or JSP file) on the server. |
PortletResponse |
The
PortletResponse defines the base interface to assist a
portlet in creating and sending a response to the client. |
PortletSession |
The
PortletSession interface provides a way to identify a user
across more than one request and to store transient information about that user. |
PortletURL |
The
PortletURL interface represents a URL
that reference the portlet itself. |
PreferencesValidator |
The
PreferencesValidator allows to validate the set of
preferences of the associated portlet just before they are
stored in the persistent store. |
RenderRequest |
The
RenderRequest represents the request sent to the portlet
to handle a render. |
RenderResponse |
The
RenderResponse defines an object to assist a portlet in
sending a response to the portal. |
Class | Description |
---|---|
GenericPortlet |
The
GenericPortlet class provides a default implementation
for the Portlet interface. |
PortletMode |
The
PortletMode class represents
the possible modes that a portlet can assume. |
PortletSessionUtil |
The
PortletSessionUtil class helps identify and decode
attributes in the PORTLET_SCOPE scope of the PortletSession
when accessed through the HttpSession an from within calls to methods
of the HttpSessionBindingListener interface. |
WindowState |
The
WindowState class represents
the possible window states that a portlet window can assume. |
Exception | Description |
---|---|
PortletException |
The
PortletException class defines a general exception
that a portlet can throw when it is unable to perform its operation
successfully. |
PortletModeException |
The
PortletModeException is thrown when a portlet
tries to use or set a portlet mode that is not supported by the current
runtime environment or the portlet. |
PortletSecurityException |
A portlet should throw a
PortletSecurityException
when a call fails because of security reasons.Additionally it can be thrown by the portal/portlet-container. |
ReadOnlyException |
The
ReadOnlyException is thrown when a portlet tries
to change the value for a read-only preference attribute. |
UnavailableException |
The portlet should throw the
UnavailableException when
the portlet is either temporarily or permanently unavailable to handle requests. |
UnmodifiableException |
The
UnmodifiableException is thrown when
a portlet tries to change the value for a preference
attribute, marked as unmodifiable in the deployment descriptor
with the non-modifiable tag, without
the needed permissions. |
ValidatorException |
The
ValidatorException is thrown by the
validate method of a PreferencesValidator when
the validation of a preference failed. |
WindowStateException |
The
WindowStateException is thrown when a portlet
tries to use a window state that is not supported by the current
runtime environment or the portlet. |