- An interaction diagram is a graphical representation of how objects interact with one another in a scenario.
- They capture the behavior of a single use case, showing the pattern of interaction among objects.
- Objects communicate in an interaction diagram by sending messages.
- Sending a message typically corresponds to invoking a method or function, where the message name is the name of the method.
- A message may carry data as parameters being passed.
UML provides two forms of interaction diagrams :
A. Sequence diagrams
B. Collaboration diagrams
Since we have only sequence diagram here are some tips and some information about sequence diagram
Sequence Diagram shows an interaction arranged in a time sequence. It has two dimensions :
1.Vertical Dimension representing time
2.Horizontal Dimension representing different objects.
Sequence Diagram : Objects
- An object is shown as a box of at the top of the dashed vertical line also know as the lifeline of the object.
- It represents the object’s existence during the interaction.
Sequence Diagram : Message
- An interaction is a set of messages exchanged among a set of objects to accomplish a particular purpose within a given context (such as a collaboration).
- A message is a conveyance of information from one object to one or more other objects with the expectation that activity will ensue, in the form of an action.
- A message can be either a signal or a call.
- Within a process or a thread, messages are ordered in sequence by time.
Sequence Diagram : Recursion And Delegation
An Example: Sequence Diagram of An Airline Reservation Syatem