Specifies ExpressionInterface classes
that can (potentially) contain a data item as part of their expression. For example,
the expression can be used in a ResourceAwareStringExpression (RASE). For example, SUM(<<DataItem1>>).
Or the expression may be modeled as an expression tree for example, a ConditionalExpression on a
DataItem filter. Note the DataItems can be nested to any depth within
an expression. In the RASE example above, <<DataItem1>> may contain an expession
with other dataitems in it. This interface does not impose limitations
on anything else the expression may contain.
Given these types of expressions, it is very useful to find out if such expressions
contain user typed aggregation, or obtain a list of leaf dataitems.
There may be other uses in the future.
For example, there is a need to run a query with detail usage on a dataitem
for supporting ROLAP with calculated items.
Using this interface a list of leaf items may be obtained from the dataitem's expression
which can then be used in a detail query.
Field Summary
Fields inherited from interface com.sas.iquery.metadata.business.ModelItem
Return a list of leaf data items. A leaf data item is a data item which
does not contain measure data items as part of their expression.
The typical usage is to get those data items which can return detail
information by ignoring their aggregate function.
The returned list does not contain duplicates. If the same leaf
data item appears more than once in the expression, the returned list
will contain the data item only once.
A data item can be both an expression and a leaf data item. Therefore,
a data item when treated as an expression may return itself from this
method.
Returns:
List of data items. The list may be empty, but is never null.
The list does not contain duplicate data items.
