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By default, when pattern users configure an instance of a
user-defined pattern, all the parameter groups that are defined in
the user-defined pattern are enabled. Enabled parameter groups and
pattern parameters within those groups are visible to pattern users
in the Configure Parameters page. You can control whether a parameter
group in an instance of a user-defined pattern is enabled by using
an XPath expression:
- If the expression evaluates to Boolean true, the parameter group is
enabled. When a pattern user configures an instance of a user-defined
pattern, the parameter group and pattern parameters within that group
are visible to pattern users in the Configure Parameters page. The
values of pattern parameters within enabled parameter groups populate
the target properties of the user-defined pattern.
- If the expression evaluates to Boolean false, the parameter group is
disabled. When a pattern user configures an instance of a user-defined
pattern, the parameter group is not shown to pattern users in the
Configure Parameters page. Pattern parameters within disabled groups
are not shown to pattern users and the values of those parameters
do not populate the target properties in an instance of the user-defined
pattern.
If no XPath expression is entered for a parameter group, the
parameter group is enabled. For XPath reference information, including
information about XPath functions, see
W3C XPath 1.0 Specification.
The
pp:getValue() function
is included, in addition to the functions in the XPath 1.0 Specification.
The
pp:getValue() function takes the parameter ID
of a pattern parameter and returns the value of that pattern parameter.
To see the parameter ID for a pattern parameter:
- In the Pattern
Configuration tab of the
Pattern Authoring editor, double-click a parameter group, or select
a parameter group and click Edit. The Edit
Group window opens.
- Click the Visibility tab. The parameter
IDs for pattern parameters are shown in the Parameter ID column
of the Pattern Parameters table. To change parameter IDs, see Changing pattern parameter IDs.
To control whether a pattern parameter group is enabled
by using an XPath expression: