Portlet Study Notes (1)

    A portlet is a server side application that runs in the context of the WebSphere Portal Server. It inherits from the javax.servlet.http.HttpServlet class and as such is treated as a servlet by the application server. However , the portlets are administered more dynamically than servlets. It is easy to install , remove , change , create and delete.

The processes of the portlets concept :

Step 1:
    The portal administrator uses the administrative interface to deploy a new portlet application WAR file or install a copy of a portlet.
Step 2:
    The portlet is placed on a page by a user or an administrator. This creates a concrete portlet instance, which is a concrete portlet parameterized by a single PortletData object.
Step 3:
    The scope of the PortletData depends on the scope of the page that the concrete portlet is on.
    1. If an administrator puts a concrete portlet on a group page, then the PortletData object contains data stored for the group of users. This holds true for a group of users who have view access to the page. However, if users have edit access to the portlet on a group page, then a new concrete portlet instance is created for each user that edits the portlet. In this case, PortletData contains data for each user that edits the portlet.

    2. If a concrete portlet is put on a user's page, the PortletData contains data for that user.When a user accesses a page that contains a portlet, that creates a user portlet instance. When a user logs into the portal, the portal server creates a PortletSession for each of the user's portlets. A concrete portlet instance parameterized by a PortletSession is known as a user portlet instance. There can be many user portlet instances per concrete portlet instance. A user portlet instance is a concrete portlet instance parameterized by a single PortletSession. There can be many user portlet instances per concrete portlet instance. The PortletSession stores transient information related to a single use of the portlet.