Type casting refines the results of a query and allows Rational® Publishing Engine to treat
.xsd schema types as being from a different type, similar to cast operations in
programming languages. A type is not assigned to schema elements that can have more than one valid
type. You define the types for these elements with the cast to type feature in
the Data Source View.
About this task
Type casting works as an alternate filter for data source elements. A cast query
filters the results of the regular query to return only the elements that can be cast to the
selected type. After the type is selected, it becomes available in the Data Source
View under the anyType element. Queries built using cast allow
access to all the child elements and attributes of the type cast. The result set returned by a cast
query is identical to the result set returned by a query that is filtered with an equivalent
IsKindOf predicate. The difference between the cast query and filtered query
is that a cast query gives access to the cast type attributes and child elements while the filtered
query does not.
Note: IBM® Rational Rhapsody®
data source supports type casting.
Procedure
- Drag a
Container element into the
template content editor.
- From the Data Source View, drag the ownedMember
class into template.
- Name the container Class Container for
quick reference.
- Click the
icon and select the Class type
cast for the ownedMember.
- Drag a
Paragraph element and place
it below the container element, and add the name of the package inside
the Class Container by dragging the Name(string) attribute.
- Drag a
Text element to the template
content editor.
- From the Data Source View, drag the static text
(Active) to the text element.
- Right-click the text element, and then click .
- In the Set Condition for Current Element window,
expand Attributes, and select the check box
for IsActive attribute.
- For the Left operand , select IsActive.
- For the Operator, select Equals.
- For the Right operand, enter true.
- Click Add. The
condition displays as: IsActive == "true"
- Click OK.
Results
Adding a Class cast to the ownedMember element
of a package allows you to define the following query, which returns
only the definitions that are classes from the same context: