Differential page rendering

You can familiarize yourself with the rendering model of the Web 2.0 theme.

The server side rendering model on which the portal Web 2.0 theme is based is called Differential Page Rendering (DPR). The concept of DPR is to render only those parts of a portal page that were affected by the a user interaction.

For example, if a user interacts with a single self-contained portlet that runs in the Web 2.0 theme, the portal refreshes only this portlet rather than the entire portal page. Beyond that, DPR detects dependencies between portlets. Accordingly, if a user interacts with a portlet that communicates with other portlets on the same page, the portal causes the Web 2.0 theme to refresh these portlets as well. The dependency detection mechanism supports the following portlet communication APIs and models:

• Portlets that communicate via events. This applies to JSR 286 compliant portlets only.

• Portlets that share public render parameters. This applies to JSR 286 compliant portlets only.

• Portlets that communicate via the property broker infrastructure.

• Portlets in a portlet application that exchange data via a shared portlet session.

In addition to using one of the APIs listed above, you can also set the following portlet initialization parameter for standard portlets or the respective configuration parameter for IBM portlets in the portlet deployment descriptor to enforce that all other portlets in the same portlet application are refreshed:

wps.csa.enforce.refresh = ( false )

Use this parameter to enable or disable the portlet application dependency filter for a portlet. Default is false. If you set this parameter to true, all portlets in the portlet application are considered to be dependent on each other.

Example:

<init-param>
   <name>wps.csa.enforce.refresh</name>
   <value>true</value>
</init-param>

For example, if your portlet application contains two portlets P1 and P2, and portlet P1 declares the initialization parameter, portlet P2 is always refreshed when it interacts with portlet P1.

This does not imply that portlet P1 is refreshed when it interacts with portlet P2. To achieve this, have the portlet P2 also declare the initialization parameter.

Parent topic:

Web 2.0 theme

Related concepts

Use the portal Web 2.0 theme
Customize the Web 2.0 theme

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