25.1.9.1.11.3.2 Computing Subject and Action Values

Compute task subject text and action values in the Actions Source query.

The Purchase Office Supplies task definition in this example accepts two parameters. As shown below, one required parameter, P_ITEMS_TO_BUY, lets the requester list the items to purchase. A second optional parameter, P_STORE, lets them indicate a preferred store to purchase the items from. If the initiator provides both items and a preferred store, then the Subject should be:

Please Buy Coffee and Bagels at Zabar's

In contrast, if the user only supplies a value for the items to buy, the Subject should be:

Please Buy 2GB Credit Card Sized Hard Drive

The task definition Subject field does not allow HTML Directives for conditional substitution, but it is still straightforward to get a computed task subject. The figure shows the Parameters tab of the Task Definition edit page in App Builder showing one required parameter P_ITEMS_TO_BUY and one optional parameter P_STORE.

Figure 25-55 Parameters for Purchase Office Supplies Task Definition

Description of "Figure 25-55 Parameters for Purchase Office Supplies Task Definition"

Your Actions Source Query can retrieve one row containing any number of columns to provide information to reference in the task definition's Subject or actions. Notice below that the query computes a dynamic subject line using a CASE expression to include the optional store information in the title.

It also invokes the OWNER_EMAILS_FOR_TASK function to retrieve a comma-separated list of emails of the potential owners. You can then reference the COMPUTED_SUBJECT and POTENTIAL_OWNER_EMAILS column aliases wherever needed in the task definition. The query looks like this:

select 'Please Buy '
       ||:P_ITEMS_TO_BUY
       ||case 
            when :P_STORE is not null 
            then ' at '||:P_STORE 
         end as computed_subject,
       your_app_pkg.owner_emails_for_task(:APEX$TASK_ID, :APEX$DETAIL_PK) 
             as potential_owners_emails
from dual

As shown below, the task definition's Subject references the dynamically computed subject using the &COMPUTED_SUBJECT. notation. The figure shows the Settings tab of the Task Definition edit page in App Builder and highlights how the Subject can use &COMPUTED_SUBJECT. to reference a column from the Actions SQL Query.

Figure 25-56 Actions Source Query Retrieves Computed Title and Potential Owner Emails

Description of "Figure 25-56 Actions Source Query Retrieves Computed Title and Potential Owner Emails"