2017-02-07 Timing Diagram

2017-02-07 Timing Diagram

Timing Diagram

Overview

Time series diagrams are interactive diagrams that emphasize the chronological order of messages.

Shitu describes the time order in which messages are routed between objects, which is used to denote the order of behavior in a use case.

Shitu represents an interaction as a two-dimensional graph in which the vertical axis is the timeline and the time extends downward along the vertical bar. The horizontal axis represents the individual objects in the collaboration.

Composition of the Shitu

The Shitu contains 4 elements:

Objects (object)

Lifeline (Lifeline)

Messages (Message)

Active (Activation (Activation |ˌæktɪˈveɪʃn| n activation, start, activation))

Object:

The symbols for objects in a time series diagram are the same as those used in objects in the object graph.

Placing an object at the top of the timeline means that the object already exists at the beginning of the interaction, and that if the object's position is not at the top, the object is created during the interaction.

Lifeline:

A lifeline is a vertical dashed line that represents the existence of an object in a sequence diagram for a period of time. The bottom center of each object has a lifeline at its location.

A lifeline is a timeline that extends from the top of the timing diagram to the bottom, depending on how long the interaction lasts.

objects, together with Lifelines, are called lifelines of objects, and the object's lifeline contains the rectangle's object icon and the lifeline below the icon.

News

Messages can be used to pass parameters between objects.

The message can be a signal, or it can be a call.

In UML, messages are represented by arrows, and the type of the header represents the type of message.

A message is a single-channel communication between two objects, from the sender to the receiver's control flow.

A message defines some form of communication between objects that can fire an action, evoke a signal, or cause a target object to be created or revoked.

Activated

Activation means that the object is occupied to complete a task, and [deactivate] refers to the object being idle and waiting for a message.

In UML, to represent an object when it is activated, the object's lifeline can be widened to be called a rectangle. The rectangle is called the activation bar or control period, and the object is activated at the top of the activation bar, and the object is activated after completing its work.

Creation and revocation of objects

An object cannot exist until a message has been created, and the object's lifeline exists only after the message is created.

If the object is at the top of the timing diagram, the object already exists before the interaction begins. If an object is created during an interaction, it should be in the middle part of the diagram.

Two ways to create an object:

If you want to undo an object, simply place an "X" symbol at its lifeline termination point, which is usually a response to a delete or cancel message.

Time series diagrams are used to denote the order of behavior in a use case.

Show the interaction between objects.

Represents the chronological order in which messages are routed between objects.