Contents
What are combined fragments?
A Combined Fragment reflects one or more aspects of interaction (called interaction operands) controlled by an interaction operator, with corresponding Boolean conditions known as interaction constraints. The Fragment displays as a transparent window, divided by horizontal lines for each operand.
What is Alt combined fragment?
An alternative combined fragment is used to specify an area of a group of lifelines/ actors to show conditional flow in a sequence diagram. It also models the if-then-else logic in the sequence diagram.
What is interaction fragment?
An interaction fragment allows you to group related messages in a sequence diagram. Various predefined fragment types are available allowing you to specify alternate outcomes, parallel messages, or looping. An interaction fragment can be created in the following diagrams: Sequence Diagram.
How many operands does an alt combined fragment have?
two interaction operands
In the previous figure, the alternative (alt) combined fragment contains two interaction operands; one with a guard condition x>5 and the other interaction operand with the guard condition x<=5 . If x=6 , the x<=5 guard condition and corresponding operand and messages run.
What does Alt mean in a sequence diagram?
alternative flow
Alt is alternative flow (SWITCH or if. IF with two paths) Opt is IF with one flow.
What is interaction fragment in sequence diagram?
In sequence diagrams, combined fragments are logical groupings, represented by a rectangle, which contain the conditional structures that affect the flow of messages. A combined fragment contains interaction operands and is defined by the interaction operator.
Which is a combined fragment in a sequence diagram?
A combined fragment consists of one or more interaction operands, and each of these encloses one or more messages, interaction uses, or combined fragments. A sequence fragment is represented as a box called a combined fragment, which encloses a portion of the interactions within a sequence diagram.
How to create a combined fragment in StarUML?
1. Click [Toolbox] -> [Sequence] -> [Interaction Operand] button. 2. And click at the Combined Fragment where Interaction Operand will be placed in the [main window]. 3. New interaction operand is added to the combined fragment. Click the interaction operand.
How is the message shown in UML sequence diagram?
The message specifies not only the kind of communication, but also the sender and the receiver. Sender and receiver are normally two occurrence specifications (points at the ends of messages). A message is shown as a line from the sender message end to the receiver message end.
What does the combined fragment operator Alt mean?
The interaction operator alt means that the combined fragment represents a choice or alternatives of behavior. At most one of the operands will be chosen. The chosen operand must have an explicit or implicit guard expression that evaluates to true at this point in the interaction.