Decision Tables Rules about different Types

Decision tables can be

• Standard Decision Tables - operate on single values or objects
• Pattern Matching Decision Tables - operate on collections of values or objects
• Functions - which operate on input arguments to produce a return value
• Class Methods - which operate on an entire class of objects
• Instance methods - which operate on a single instance of a class

The behavior of a decision table depends on what type it is

Feature	DT Standard	DT Function	DT Class Method	DT Instance Method
Input	Determined by the values tested in conditions or referenced in actions	Specified in the arguments to the function. A function may only use values formally passed in. Any assignment statements can only refer to local variables within the scope of the function	All instances of the class are default inputs along with any other arguments	The instance is the default input to the method. Additional arguments may be passed in. Properties of the instance may be referenced with just the property name. Other values need to be fully qualified.
Output	Determined by the assignment statements in the actions.	Specified as a return value	Specified as a return value. New instances may be created, deleted or modified.	Specified as a return value. An instance method may also assign values to any property of that instance.
Assignments	Any data element may be modified	No data elements may be modified (except local variables)	Only properties of the class may be modified	Only properties of the instance may be modified
Local Variables
Inferencing	BC and FC
Examples	Standard DT	DT Function	DT Class Method	DT Instance Method