Features of cooperative portlets
Certain features of cooperative portlets make them easier to use. Some of these features include property transfers saved as wires, chained propagation of data transfer, user-friendly interfaces, and advanced programming options, depending on whether they are standard portlets or IBM portlets.
Features available to standard and IBM portlets:
- Property transfers saved as wires:
Users and administrators can create wires between cooperative portlets using the Portlet Wiring Tool.
For IBM portlets only, depending on the browser, users can hold either the CTRL or ALT key while clicking on a Click-to-Action icon to save the property transfer preferences as wires between portlets. The next time the user clicks on the icon, the saved menu selection is used and the property is transferred without prompting the user.
- Chained propagation of data transfer
Sending data to one portlet can cause that portlet to send data to another portlet, which can in turn transmit data. This feature supports the synchronization of multiple portlet views in a single request-response cycle. For example, transferring the order ID to the Order Details portlet also triggers the transfer of the tracking ID for the order to the tracking details portlet, which in turn triggers the transfer of the customer name associated with the order to the customer details portlet, causing all three to display information pertaining to the same order. The property broker ensures that chained propagation does not turn into endless looping.
Chained propagation works only when wires have been setup between the cooperative portlets. This feature can be enabled by specifying output parameters for the portlet. When the target receives data from a source, this can in turn cause the transfer of one or more output parameters values.
- Simple enablement for portlet development
- For a portlet to be a source of data, programmers can use a WSDL file to flag sharable data on their output pages. For IBM portlets only, a custom JSP tag library can be used. These tags require a data type to be specified as well as a specific value corresponding to an instance of this type.
- For a portlet to be a target, programmers describe a subset of their portlet actions, including type information for the action parameters. For standard and IBM portlets, WSDL with some custom extensions is a supported format for declaring actions and their associated parameters. For IBM portlets only, this can also be achieved programmatically.
For standard portlets, WSDL is the only way to provide information on portlet actions.
- Broadcast source data to all matching actions
Users can create wires from a single source property to multiple target portlets. If it is a cross page wire, then the multiple target portlets must be on the same page. For IBM portlets only, end users of the Click-to-Action function can specify the target of the action or broadcast the action to all portlets. This feature is available in the source portlet when the broadcast attribute is specified for the <c2a:encodeProperty/> tag.
IBM portlets only:
- User-friendly interface
Cooperative portlets provide an easy, menu-driven method to enable the sharing of compatible data between portlets.
- Scatter multiple related sources to targets with a single click
The Click-to-Action menu can allow users to send multiple property values with a single click. For example, the Order Summary portlet in the Order Shipping
Example has a "Send to all" pop-up menu item, which allows the user to transfer the properties in the selected row (the order ID and customer ID) to all actions on the page which can consume any of the properties. As a result, all portlets on the page display information about the same order - the scatter feature, combined with the chained data transfer feature, has resulted in the synchronization of all the information on the page through a single user click.
- Advanced programming features
The setProperties() method in the PropertyListener interface can be used in place of the actionPerformed() method in the ActionListener interface for other programming needs. This allows changes to any property which the portlet is interested in to be received through a single, generic method, instead of requiring multiple actions to be declared. For example, we can process the property and save it in a bean without performing any action. We can also attach the Click-to-Action menu to custom markup elements using the getActionTriggerMarkup() method.
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