Guard-related constructs are described below.
Guard
A guard is an expression that evaluates to a boolean value. Guards are used within transitions to determine whether a transition is taken.
Listing 5: A Guard construct.
The following keywords can/must be provided:
Keyword | Description | Type | Optional |
---|---|---|---|
expression | The guard expression. | Expression | No |
expression
The expression keyword specifies the guard expression.
The guard expression must evaluate to a boolean value.