Expressions — How to reference parts of aggregate properties

Use the standard dot notation to reference the value of a property on a page:

pagename.propertyname

This notation works for both getting a value and setting a value.

Lists

For Value List and Page List properties, the index is a number starting with 1. To reference a single element of the list, use an expression that evaluates to a positive integer value.

For example, you can set the first two elements of the Value List property named Months using a data transform's Set action or using the Property-Set method as follows:

Numeric indexes work similarly for a Page List property. The LoanApplications Page List property contains a Single Value property named LoanAmount:

Groups

Each element of a Value Group or Page Group property is identified by a unique value that must be a Java identifier. You can enter a constant string as the index, such as Mother or Massachusetts:

You can also enter an expression that evaluates to a string value. The result must be a valid Java identifier.

On the Clipboard tool display, Value Group values appear on the right panel:

Use keywords to identify certain elements of aggregate properties.

<APPEND> index

To add an element to the end (highest index value) a Value List or Page List property, use the <APPEND> index keyword:

This keyword is meaningful only in target property references, not expressions.

<LAST> index

To set or retrieve an element value from the end (highest index value) a Value List or Page List property, use the <LAST> index keyword.

For example, this sets the value of the highest numbered element in the Month Value List property:

Similarly, this sets the LoanAmount value in the highest-numbered LoanApplication page:

<INSERT > index

Use the <INSERT> keyword followed by an integer to insert a new element and its value into a Value List or Page List property at a numeric index position. Any elements with the same or higher index value are "pushed down" by one.

This keyword can only be used in target property references, not expressions. You can use a literal number for the index:

or a numeric property reference for the index:

If the integer is equal to the size of the list, or greater by one, PRPC inserts the new value as a new last element. If the integer is larger than the size of the list by 2 or more, PRPC creates an exception.

<PREPEND> index

Use the <PREPEND> keyword insert a new element and its value into a Value List or Page List property as the first element. All existing elements are "pushed down" by one.

This keyword can only be used in target property references, not expressions.

<CURRENT> index

Within a single activity step, you can set up an iteration that performs a repeated computation over a collection, such as all the elements in a Value List property. In that context, the <CURRENT> index identifies the index value for the current iteration.

See Activity form — Completing the Steps tab (Iteration).