systemcomposer.interaction.Lifeline

Lifeline in interaction

Since R2024a

Description

A Lifeline object represents a participant in an interaction. A lifeline sends and receives messages between other participants. On the sequence diagram representing the interaction, a lifeline is shown as a vertical line with a header at the top containing the name of the lifeline. A lifeline corresponds to a component in the architecture model.

Lifelines can have at most one parent lifeline, and zero or more children lifelines. Children are represented in the sequence diagram as vertical lines with headers that are drawn underneath the parent lifeline.

Creation

Access Lifeline objects via the RootFragment property of the corresponding systemcomposer.interaction.Interaction object. Access the CoveredLifelines property of the root fragment to inspect all the lifelines.

Properties

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`Name` — Name of lifeline
string

Name of lifeline, specified as a string.

Example: "mechanicsComponent"

Data Types: string

`FullPath` — Full path of lifeline
string

Full path of lifeline, specified as a string.

Example: "mySequenceDiagram/mechanicsComponent"

Data Types: string

`Parent` — Parent lifeline
lifeline object

Parent lifeline, specified as a systemcomposer.interaction.Lifeline object.

`Children` — Array of child lifelines
array of lifeline objects

Array of child lifelines, specified as an array of systemcomposer.interaction.Lifeline objects.

`RelatedElements` — Component represented by lifeline
component object

Component represented by lifeline, specified as a systemcomposer.arch.Component object.

`ExternalUID` — Unique external identifier
character vector

Unique external identifier, specified as a character vector. The external ID is preserved over the lifespan of the element and through all operations that preserve the UUID.

Data Types: char

`UUID` — Universal unique identifier
character vector

Universal unique identifier, specified as a character vector.

Example: '91d5de2c-b14c-4c76-a5d6-5dd0037c52df'

Data Types: char

Object Functions

`move`	Move lifeline within an interaction
`destroy`	Remove model element

Examples

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Inspect Sequence Diagrams with Programmatic Interfaces

Open Live Script

You can use read-only API workflows to navigate sequence diagrams in System Composer™ and display information about each element.

Open Traffic Light Example

Open the traffic light example architecture model so that you can inspect the sequence diagrams visually and confirm the programmatic outputs.

model = systemcomposer.openModel("TLExample");

To view the sequence diagrams associated with the model, on the System Composer toolstrip, navigate to Modeling > Sequence Diagram.

The press detection sequence diagram in the views gallery of the top model.

Programmatically Navigate Sequence Diagram

Collect the sequence diagrams represented by interactions that contain specific interactions of elements in the model.

interactions = model.getInteractions;

For the first interaction, extract the name of the sequence diagram.

disp("The first sequence diagram is called " + interactions(1).Name + ".")

The first sequence diagram is called Inhibit.

For this sequence diagram, display each lifeline and the component the lifeline represents.

for i = 1:length(interactions(1).Lifelines)
    disp("The " + interactions(1).Lifelines(i).Name + ...
    " lifeline represents the " + ...
    interactions(1).Lifelines(i).RelatedElements.Name + ...
    " component.")
end

The source lifeline represents the source component.
The poller lifeline represents the poller component.
The switch lifeline represents the switch component.
The controller lifeline represents the controller component.
The lampController lifeline represents the lampController component.

Display the contents of one message in the root fragment.

disp("The sequence diagram message starting at the " + ...
    interactions(1).RootFragment.Operands.Fragments(1).Name + ...
    " message end is of type " + ...
    string(interactions(1).RootFragment.Operands.Fragments(1).Message.Type) + ...
    " and the message label is " + ...
    interactions(1).RootFragment.Operands.Fragments(1).Message.Condition + ".")

The sequence diagram message starting at the switchout message end is of type Signal and the message label is rising(sw-1){sw==1}.

Use Iterator Utility to Step Through Sequence Diagram

Step through the Inhibit sequence diagram using the Iterator utility.

interaction = model.getInteraction('Inhibit');
interaction.open

Inhibit sequence diagram from the top model.

Display the annotation from the interaction.

disp(interaction.Annotations.Content)

When inhibit is true, it means pedestrian crossing is not controlled by a walk signal on this intersection.

Use an iterator to navigate through all elements of a sequence diagram before extracting their properties.

iterator = systemcomposer.interaction.Iterator(interaction.RootFragment);
next = iterator.next;
while ~isempty(next)
    disp(class(next))
    next = iterator.next;
end

systemcomposer.interaction.RootFragment
systemcomposer.interaction.Operand
systemcomposer.interaction.MessageEvent
systemcomposer.interaction.MessageEvent
systemcomposer.interaction.MessageEvent
systemcomposer.interaction.MessageEvent
systemcomposer.interaction.AltFragment
systemcomposer.interaction.Operand
systemcomposer.interaction.MessageEvent
systemcomposer.interaction.MessageEvent
systemcomposer.interaction.MessageEvent
systemcomposer.interaction.MessageEvent
systemcomposer.interaction.Operand
systemcomposer.interaction.MessageEvent
systemcomposer.interaction.MessageEvent

More About

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Definitions

Term	Definition	Application	More Information
sequence diagram	A sequence diagram represents the expected interaction between structural elements of an architecture as a sequence of message exchanges.	Use sequence diagrams to describe how the parts of a system interact.	Describe System Behavior Using Sequence Diagrams
lifeline	A lifeline is represented by a head and a timeline that proceeds down a vertical dotted line.	The head of a lifeline represents a component in an architecture model.	Add Lifelines and Messages
message	A message sends information from one lifeline to another. Messages are specified with a message label.	A message label has a trigger, an optional guard, and an optional constraint where a trigger represents the identifying event for this message, a guard represents an additional condition to determine whether the message occurs, and a constraint is an expression that is expected to be true when this message occurs.	Create Messages in Sequence Diagram
gate	A gate represents the root architecture of the corresponding architecture model.	Connect messages to gates to represent architecture ports.	Create Sequence Diagram Gates
annotation	An annotation describes the elements of a sequence diagram.	Use annotations to provide detailed explanations of elements or workflows captured by sequence diagrams.	Use Annotations to Describe Elements of Sequence Diagram
fragment	A fragment indicates how a group of messages execute or interact.	A fragment is used to model complex sequences, such as alternatives, in a sequence diagram.	Author Sequence Diagram Fragments
operand	An operand is a region in a fragment. Fragments have one or more operands depending on the kind of fragment. Operands can contain messages and additional fragments.	Each operand can include a constraint to specify whether the messages inside the operand execute. You can express the precondition of an operand as a MATLAB^® Boolean expression using the input signal of a lifeline.	Add Fragments and Operands

Version History

Introduced in R2024a

systemcomposer.interaction.Lifeline

Description

Creation

Properties

`Name` — Name of lifeline
string

`FullPath` — Full path of lifeline
string

`Parent` — Parent lifeline
lifeline object

`Children` — Array of child lifelines
array of lifeline objects

`RelatedElements` — Component represented by lifeline
component object

`ExternalUID` — Unique external identifier
character vector

`UUID` — Universal unique identifier
character vector

Object Functions

Examples

Inspect Sequence Diagrams with Programmatic Interfaces

More About

Definitions

Version History

See Also

Tools

Functions

Objects

Topics

systemcomposer.interaction.Lifeline

Description

Creation

Properties

Name — Name of lifeline string

FullPath — Full path of lifeline string

Parent — Parent lifeline lifeline object

Children — Array of child lifelines array of lifeline objects

RelatedElements — Component represented by lifeline component object

ExternalUID — Unique external identifier character vector

UUID — Universal unique identifier character vector

Object Functions

Examples

Inspect Sequence Diagrams with Programmatic Interfaces

More About

Definitions

Version History

See Also

Tools

Functions

Objects

Topics

`Name` — Name of lifeline
string

`FullPath` — Full path of lifeline
string

`Parent` — Parent lifeline
lifeline object

`Children` — Array of child lifelines
array of lifeline objects

`RelatedElements` — Component represented by lifeline
component object

`ExternalUID` — Unique external identifier
character vector

`UUID` — Universal unique identifier
character vector