Using the timing diagram shows the interaction between objects, dynamic display by collaboration between a plurality of objects described in chronological order of sending messages between objects used to represent the order in which activities use cases.
A timing diagram Features
1, with the specific details described embodiment.
2, calls for complex logic, function and operation of the modeling.
3, shows how between objects, components interact.
4, understand the old code, planning a new scene.
Second, the basic elements
Character (the Actor), the object (Object), Lifeline (Lifeline), controls the focus (Activation), message (the Message), self-association message, fragment combination. First six more commonly used, but also more important.
1. Role
System roles, can be people, and even other systems or subsystems.
2, Object
The entire interaction process entities, may be a concrete class may also be another system. Objects can be represented by the following diagram:
Objects include three are named:
- Object names and class names;
- Show only the class name does not display the object name, the anonymous class;
- Displays object name does not display the name of the class;
3, lifeline
And a timing chart of each object in the center of the bottom has a vertical dashed line, which is the object of the lifeline (Timeline object). Represented by a vertical dashed line.
4, the focus control
Controlling the operation timing chart representative of the focus in the object execution timeline of a certain period, it indicates the effective duration of the operation. In a very narrow rectangle.
5, news
Information representing objects send to each other. The message is divided into three types:
- Synchronization message (Synchronous Message): the sender of the message recipient to control the message transmitted, then ceased, waiting for the recipient of the message or return control to abandon. Used to indicate the significance of synchronization. + Solid in a solid line arrow.
- Asynchronous message (Asynchronous Message): the message sender to the recipient of the message signal transmitted by the message, and then continue their activities without waiting for the recipient to return a message or control. Asynchronous receiver and sender of the message is concurrent work. In a solid line represents a number greater than +.
- Return message (Return Message): Returns the message indicates that the returns from the procedure call. No less than + dashed lines.
6, since the association message
The method calls itself represents a method call or other methods within the object. In a semi-closed rectangular solid cutting head represented below +.
7, a combination of segments
Combined Fragment conditions and interact to solve execution, which allows direct sequence diagram showing the logical components, by specifying conditions for application area or sub-process, any part of the definition of special conditions and any child processes lifeline.
- ref: reference composition fragment defined elsewhere;
- alt: In a set of behaviors in an interactive selection according to specific conditions;
- opt: represents an optional behavior;
- break: programming language provides a mechanism and the break of Quasi;
- par: supporting interactive fragment of concurrent execution;
- seq: Forced interaction performed in a particular order;
- strict: clearly defined execution order of a group of interactive segments;
- neg: used to interact mark should not have happened;
- region: interactive sign ahead of other interactive pieces take place in the combined segment;
- ignore: the message interaction defined fragments should not respond;
- consider: a clear sign the message should be processed
- assert: sign in interactive segments as operands events only legitimate successor to the;
- loop: Description will be repeatedly executed interactive fragment
Third, the basic example
Docking WPS online editing services, timing diagrams used in accordance with the chronological order execution, and ultimately get the files back-end server, the front js in online editing word documents.
So far, relevant content for UML Sequence Diagram made a rough summary of the timing diagram for the design or to view other systems, other docking systems, the timing diagram provided, to know how to identify, how to design.
2020-03-20,望技术有成后能回来看见自己的脚步