software engr mid2

Sequence diagram

Illustrates how components interact over time to complete a specific functionality in a system

Interaction diagrams

Used to represent communication and behavior between system parts during execution

Sequence diagram purpose

Focuses on ordered interactions between participants within a single scenario

Sequence diagram timeline

Time flows vertically downward indicating the order of operations

Lifeline notation

Represents the existence of a participant during the interaction period

Lifeline arrangement

Participants are placed horizontally and remain distinct without overlapping

Actor lifeline

Used to depict an external role interacting with the system

Entity lifeline

Used to represent stored data or persistent information components

Boundary lifeline

Represents interface elements through which users or systems interact

Control lifeline

Handles coordination and logic between interface and data components

Activation bar

Indicates the duration during which a participant is performing an operation

Activation bar meaning

Shows when execution is taking place within a participant

Message arrow

Represents communication or invocation between participants

Message signature

Describes the format of a message including name, parameters, and return type

Synchronous message

Execution pauses until a response is received before proceeding

Synchronous notation

Displayed using a filled arrowhead

Asynchronous message

Execution continues immediately without waiting for a response

Asynchronous notation

Displayed using an open arrowhead

Return message

Represents the completion of processing and transfer of control back

Return message notation

Displayed using a dashed arrow

Participant creation message

Indicates that a new participant begins existence during the interaction

Participant destruction message

Indicates termination of a participant before completion

Reflexive message

Occurs when processing is handled internally within the same participant

Self message meaning

Represents internal logic or computation without external interaction

Sequence diagram layout

Participants are aligned horizontally and interactions occur vertically

Loop notation (*)

Indicates repeated execution of a set of interactions

alt fragment

Represents branching behavior with multiple possible paths

opt fragment

Represents conditional execution of a single optional path

Message passing (UML)

Describes communication where one component triggers behavior in another

Message passing (AutoGen)

Communication occurs through structured exchanges such as prompts and responses

Sequence diagram vs AutoGen

Both describe systems where communication drives behavior over time

Method call in UML

Represents invocation of behavior on another component

Method call in AutoGen

Represents sending a request or executing a capability through an agent

Tool invocation

Execution of an external capability triggered by an agent

AssistantAgent

Component responsible for reasoning and generating outputs using language models

UserProxyAgent

Component representing human input and enabling user involvement

UserProxyAgent notation

Modeled similarly to an external role interacting with the system

Backend LLM role

Provides intelligence for processing, reasoning, and generating responses

CodeExecutorAgent

Executes generated instructions within a controlled environment

Agent communication cycle

Process involving input, processing, response, and iterative collaboration

Agent message types

Includes text exchanges, execution requests, results, and completion signals

Agentic AI

System composed of multiple independent components working together toward a goal

Agentic AI characteristics

Includes autonomy, collaboration, iteration, and ability to use tools

Agent lifecycle

Components are dynamically created, perform tasks, and are terminated afterward

Super agent

Coordinates multiple components and manages their lifecycle

Sub-agents

Perform specialized tasks independently or collaboratively

Concurrency in AutoGen

Multiple components execute tasks simultaneously without blocking each other

State diagram

Represents how a single component behaves through different conditions over time

State

Represents a condition during which behavior or waiting occurs

Transition

Defines movement between conditions based on triggers

Event trigger

Stimulus that causes a change from one condition to another

Guard condition

Constraint that must be satisfied before a change occurs

Action

Operation executed as part of a change between conditions

Initial state

Starting point of behavior representation

Final state

Indicates completion of behavior execution

Self-transition

Represents a change that begins and ends in the same condition

Concurrent substates

Multiple conditions active simultaneously within a larger context

Sequential substates

Conditions that occur one after another within a larger context

State machine

Defines how behavior progresses through different conditions over time

State machine use

Applied in systems that respond to external or asynchronous inputs

Entry action

Executed when entering a condition

Exit action

Executed when leaving a condition

Internal transition

Handled without leaving the current condition

Deferred event

Delayed until a more appropriate condition is reached

Class diagram

Describes system structure including components and relationships

Class

Defines properties and behaviors shared by a group of objects

Attribute

Represents data stored within a component

Operation

Defines behavior that can be performed by a component

Inheritance

Represents specialization where one component builds on another

Composition

Represents strong ownership where parts depend entirely on the whole

Aggregation

Represents weak ownership where parts exist independently

Association

Represents a general connection between components

Dependency

Represents a temporary reliance between components

Multiplicity

Specifies the number of related instances between components

Use case diagram

Describes system functionality from an external perspective

Actor (use case)

Represents an external role interacting with the system

Use case

Represents a complete functionality delivered to a role

Use case model

Represents the full set of functionalities of a system

<> relationship

Represents functionality that is always required as part of another

<> relationship

Represents additional behavior that occurs under certain conditions

Include vs extend difference

Distinguishes between mandatory reuse and conditional extension

Entity element

Represents stored or persistent information

Boundary element

Represents interaction points with external entities

Control element

Represents coordination and decision-making logic

Information flow

Represents how data or control moves between components

Synchronous vs asynchronous

Differentiates between blocking and non-blocking communication

Coffee machine synchronous

User must wait until the process completes before continuing

Coffee machine asynchronous

Process continues while the user performs other actions

Object destruction notation

Marks termination of a component before interaction ends

Self-check behavior

Represents internal evaluation without external communication

Common sequence diagram mistake

Incorrect ordering or misuse of communication types

Common class diagram mistake

Overcomplicating structure or missing key relationships

Common state diagram mistake

Failing to clearly define transitions or conditions

Modeling (UML)

Process of simplifying reality to focus on relevant aspects

Model

Representation of selected aspects of a system

View

Perspective focusing on specific elements of a representation

Notation

Set of rules used to represent models visually or textually

System vs model vs view

Distinguishes real-world entity, abstraction, and perspective

Concept vs phenomenon

Differentiates between general definition and specific occurrence

Type vs instance

Differentiates between a category and a specific example