A series of steps consists of multiple Step
objects that specify the criteria for selecting a set of members for a particular dimension. The steps in a series are evaluated sequentially to determine the result set. Each step builds on the previous steps.
There are different types of Step
objects, each representing a specific method for specifying members. For example, one type of Step
object might select members explicitly by name; another type might specify members based on a condition, such as the top 10 members by Sales.
Typically, Step
objects are created when users use the QueryBuilder bean to select members of particular dimensions. Step
objects are also created by the Favorite Tool, the Rotate Tool, and the Sort Tool.
The Step
class in the oracle.dss.selection.step
package is the base class that implements behavior common to all Step
objects.
Each type of Step
object has the following characteristics:
Is represented by an instance of one of the Step
classes in the oracle.dss.selection.step
package.
Can save and restore its state based on an XML stream. However, it is persisted only as part of a Selection
object.
There are three basic types of Step
classes as described in the following list:
MemberStep
-- Specifies members explicitly by name.
ConditionStep
-- Specifies members based on a condition (that is, a rule), such as "the top 10 products based on sales."
The ConditionStep
class is an abstract class. Specific behavior for each type of step that is based on a condition is implemented in extensions of this class.
FavoriteStep
-- Specifies a favorite (that is, a previously saved selection) or one or more steps that comprise a favorite.
The following figure provides a visual representation of the hierarchy of the Step
classes in the oracle.dss.selection.step
package, as described in this topic.