A placeholder is a predefined location in a JSP that displays a single piece of Web content retrieved from the BEA Virtual Content Repository. A placeholder uses queries to retrieve and display content.
By default, placeholders support the following MIME types: HTML, XML, plain text, images, and Shockwave files. To display additional MIME types in placeholders, see Supporting Additional MIME Types.
When a user views a portal desktop or portlet containing a placeholder, the placeholder's rules and back-end logic run a query, retrieve zero or more pieces of content matching the query, and display one of the returned items. If no content is retrieved, none is displayed.
The queries for a placeholder come from two different places:
Because a placeholder can contain multiple queries, the placeholder serves as a content bucket that can display a different piece of content each time a user accesses the JSP containing the placeholder. The following procedure includes a step that lets you set a query's priority to increase or decrease the chances that the query is run instead of other queries present in the placeholder.
Placeholders are scoped to the enterprise application, so you can include Placeholders in any JSPs within the enterprise application.
For more information on placeholders, see the Interaction Management Guide on BEA's e-docs Web site.
To create a placeholder
Note: As an alternative to Placeholders, you can use the <ad:adTarget> JSP tag to hard-code a content query within the tag.
To modify a placeholder
To modify a placeholder, open its file by double-clicking it in the WebLogic Workshop Application window. Select and modify the appropriate query.
To delete a query or placeholder
To delete a query in a placeholder, open the placeholder file, select the query in the Document Structure window, and press the Delete key.
To delete a placeholder, select it in the Application window, press the Delete key, and click OK in the confirmation dialog box. Also delete any <ph:placeholder> tags in your JSPs for the deleted Placeholder.