A Formal Semantics of UML Sequence Dia-grams Xiaoshan Li, Zhiming Liu and He Jifeng Abstract This paper presents a formal semantics of UML sequence diagram. In abstract syntax form, a well-formed. Sequence diagrams map out complex architecture, but they can be surprisingly easy to create. Sequence diagrams are a popular subset to UML, so if you’re new to the topic, use our sequence diagram tutorial to familiarize yourself and find different ways you can use sequence diagrams to map out your technical process and infrastructure.
The sequence diagram represents the flow of messages in the system and is also termed as an event diagram. It helps in envisioning several dynamic scenarios. It portrays the communication between any two lifelines as a time-ordered sequence of events, such that these lifelines took part at the run time. In UML, the lifeline is represented by a vertical bar, whereas the message flow is represented by a vertical dotted line that extends across the bottom of the page. It incorporates the iterations as well as branching.
An individual participant in the sequence diagram is represented by a lifeline. It is positioned at the top of the diagram.
A role played by an entity that interacts with the subject is called as an actor. It is out of the scope of the system. It represents the role, which involves human users and external hardware or subjects. An actor may or may not represent a physical entity, but it purely depicts the role of an entity. Several distinct roles can be played by an actor or vice versa.
It is represented by a thin rectangle on the lifeline. It describes that time period in which an operation is performed by an element, such that the top and the bottom of the rectangle is associated with the initiation and the completion time, each respectively.
The messages depict the interaction between the objects and are represented by arrows. They are in the sequential order on the lifeline. The core of the sequence diagram is formed by messages and lifelines.
Following are types of messages enlisted below:
A note is the capability of attaching several remarks to the element. It basically carries useful information for the modelers.
Following are the types of fragments enlisted below;
|alt||Alternative multiple fragments: The only fragment for which the condition is true, will execute.|
|opt||Optional: If the supplied condition is true, only then the fragments will execute. It is similar to alt with only one trace.|
|par||Parallel: Parallel executes fragments.|
|loop||Loop: Fragments are run multiple times, and the basis of interaction is shown by the guard.|
|region||Critical region: Only one thread can execute a fragment at once.|
|neg||Negative: A worthless communication is shown by the fragment.|
|ref||Reference: An interaction portrayed in another diagram. In this, a frame is drawn so as to cover the lifelines involved in the communication. The parameter and return value can be explained.|
|sd||Sequence Diagram: It is used to surround the whole sequence diagram.|
An example of a high-level sequence diagram for online bookshop is given below.
Any online customer can search for a book catalog, view a description of a particular book, add a book to its shopping cart, and do checkout.
Title: Here is a titleA->B: Normal lineB-->C: Dashed lineC->>D: Open arrowD-->>A: Dashed open arrowTheme: Download as SVG
# Example of a comment.Note left of A: Note to then left of ANote right of A: Note to then right of ANote over A: Note over ANote over A,B: Note over both A and BTheme: Download as SVG
participant Cparticipant Bparticipant ANote right of A: By listing the participantsn you can change their orderTheme: Download as SVG
js-sequence-diagrams depends on Snap.svg and Underscore.js (or lodash). You can download all these files manually, or use 'bower install bramp/js-sequence-diagrams'.
How to get ip address of wireless router using. Then include the following HTML: and now you have two options. You can manually parse the text:or use jQuery to do all the work:
More documentation is in the official README.md