Variable Definitions 
Variable Definitions are those whose value can be assigned in actions of rules. You can create variable definitions on primitive data types and Java objects.
Example
Consider a Variable Definition as follows:
Name
Type
Initial Value
X
int
0
This Variable Definition can be used in an action in an If-Then rule as follows:
If
...
Then
Assign:: x = x + 10
Typical Uses
Many rules involve calculation of a crucial output parameter that is modified by other rules. In such cases the output parameters can be modified in those rules.
ExampleTo calculate interest rate, you can create a Variable Definition as follows:
Name
Type
Initial Value
double
Int Rate
0
The Variable Definition can be used in an action in an If-Then Rule as follows:
Assign :: Int Rate = 10.5
Assign :: Int Rate = Int Rate + 5
End of the example.Some actions may return intermediate values that need to be used as input for other actions. This can be achieved by using variable definitions.
ExampleConsider a Variable Definition as follows:
Name
Type
Initial Value
Temp
int
0
This Variable Definition can be used as follows:
If
...
Then
Assign :: Temp = performaction1 ()
performaction2 (Temp)
End of the example.
Clarifications
Variable Definitions can be used in conditions. When Variable Definition used in 'Assign' actions cause the values of those variable definitions to change, then these Definitions used in conditions are re-evaluated . Based on the outcome then rules are appropriately removed from or added to the Firing Queue.