systemcomposer.interaction.MessageEvent

Message end in interaction

Since R2024a

Description

A MessageEvent object represents one of the ends of a message in an interaction. A message end corresponds to a port in an architecture model.

Creation

Access MessageEvent objects via the RootFragment property of the corresponding systemcomposer.interaction.Interaction object. Iterate over the root fragment to inspect the MessageEvent objects within the fragments.

Properties

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`Name` — Name of message event
string

Name of message event, specified as a string.

Data Types: string

`Message` — Parent message
message object

Parent message, specified as a systemcomposer.interaction.Message object.

`IsMessageStart` — Whether event represents start of message
`1` (`true`) | `0` (`false`)

Whether event represents start of message, specified as 1 (true) or 0 (false).

Data Types: logical

`Parent` — Parent operand
operand object

Parent operand, specified as a systemcomposer.interaction.Operand object.

`RelatedElements` — Port represented by message event
architecture port object | component port object

Port represented by message event, specified as a systemcomposer.arch.ArchitecturePort or systemcomposer.arch.ComponentPort object.

`Lifeline` — Lifeline on which event falls
lifeline object

Lifeline on which event falls, specified as a systemcomposer.interaction.Lifeline 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

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 SignalSequence.

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 lampController lifeline represents the lampController component.
The ped lamp lifeline represents the ped lamp 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
Interaction	An interaction specifies how each part of a system should interact as a sequence of message exchanges.	Use interactions to describe operational system behaviors.	Describe System Behavior Using Sequence Diagrams
Sequence diagram	A sequence diagram is a visual representation of an interaction.	Use sequence diagrams to visually specify how each part of a system should interact.	Describe System Behavior Using Sequence Diagrams
Lifeline	A lifeline represents an instance of a component as a participant of an interaction.	A lifeline corresponds to a component in an architecture.	Describe Interactions with Lifelines and Messages
Message	A message represents communication between two lifelines. Messages have labels to specify the expected condition for the message to occur.	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.	Describe Interactions with Lifelines and Messages
Gate	A gate represents the root of an architectural hierarchy.	A gate allows you to describe the exchange of messages between the architecture and its environment.	Describe Interactions with Lifelines and Messages
Annotation	An annotation describes the elements of a sequence diagram.	Use annotations to provide detailed explanations of elements or workflows captured by sequence diagrams.	Annotate Sequence Diagrams with Annotations
Fragment	A fragment encloses a group of lifelines and messages within an interaction to allow for the specification of more complex patterns of interaction.	A fragment defines the type of ordering logic such as looping and alternatives. Fragments can have one or more operands.	Model Complex Interactions with Fragments and Operands
Operand	An operand is a region in a fragment, or group of messages. The condition of an operand specifies whether the messages inside the operand execute.	The condition of an operand can specify constraints on the input signal of a lifeline as a MATLAB^® Boolean expression.	Model Complex Interactions with Fragments and Operands
Duration constraint	A duration constraint defines a constraint on elapsed time between a start and an end occurrence.	Use duration constraints to explicitly express a constraint on the duration between a start occurrence and an end occurrence.	Specify Timing Constraints Between Message Events with Duration Constraints

Version History

Introduced in R2024a

systemcomposer.interaction.MessageEvent

Description

Creation

Properties

`Name` — Name of message event
string

`Message` — Parent message
message object

`IsMessageStart` — Whether event represents start of message
`1` (`true`) | `0` (`false`)

`Parent` — Parent operand
operand object

`RelatedElements` — Port represented by message event
architecture port object | component port object

`Lifeline` — Lifeline on which event falls
lifeline 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.MessageEvent

Description

Creation

Properties

Name — Name of message event string

Message — Parent message message object

IsMessageStart — Whether event represents start of message 1 (true) | 0 (false)

Parent — Parent operand operand object

RelatedElements — Port represented by message event architecture port object | component port object

Lifeline — Lifeline on which event falls lifeline 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 message event
string

`Message` — Parent message
message object

`IsMessageStart` — Whether event represents start of message
`1` (`true`) | `0` (`false`)

`Parent` — Parent operand
operand object

`RelatedElements` — Port represented by message event
architecture port object | component port object

`Lifeline` — Lifeline on which event falls
lifeline object

`ExternalUID` — Unique external identifier
character vector

`UUID` — Universal unique identifier
character vector