Interaction Overview Diagrams

📌 What is an Interaction Overview Diagram?

An Interaction Overview Diagram is a type of behavioral UML diagram that combines features of activity diagrams and interaction diagrams. It shows how interactions are organized and provides an overview of the flow of control between various interactions (like sequence diagrams and communication diagrams).

Purpose:

• To visualize the flow of interactions in a complex system.

• To break down high-level processes into smaller interaction diagrams.

• To coordinate multiple sequence or communication diagrams under one workflow.

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🎯 Key Elements of Interaction Overview Diagrams

Element	Description	Symbol/Notation
Initial Node (Start)	Starting point of the interaction flow	Solid black circle (●)
Final Node (End)	Ending point of the interaction flow	Hollow circle with a dot inside (◎)
Interaction (Interaction Use)	Refers to another interaction like a sequence diagram	Rounded rectangle with interaction name
Decision Node	Represents a branching based on conditions	Diamond shape (◇)
Merge Node	Merges multiple flows back into one	Diamond shape (◇)
Fork/Join Nodes	Splits or synchronizes parallel flows	Thick horizontal/vertical bars
Flow/Control Arrows	Shows direction of flow	Solid arrows (→)

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✅ When to Use Interaction Overview Diagrams

• To model complex workflows that involve multiple interactions.

• To coordinate several sequence or communication diagrams.

• To represent a high-level view of system processes with detailed interactions embedded.

• To capture conditional and parallel flows involving interactions.

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🧭 How to Create an Interaction Overview Diagram (Step-by-Step)

1. Identify the process/interaction that needs to be modeled.

2. Break down the process into smaller interactions or sequence diagrams.

3. Identify conditional flows (decisions, merges) and parallel processes (forks, joins).

4. Draw start and end nodes to define flow limits.

5. Connect interactions with control flow arrows to represent the sequence.

6. Use decision and merge nodes where conditional logic applies.

7. Review and validate the diagram with stakeholders.

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📊 Example of an Interaction Overview Diagram

Scenario: Online Shopping Process

Steps & Interactions:

1. Start

2. Browse Product Catalog (Interaction 1 - Sequence Diagram)

3. Add to Cart (Interaction 2 - Sequence Diagram)

4. Checkout (Interaction 3 - Sequence Diagram)

5. Decision: Payment Successful?

   • If Yes → Send Order Confirmation (Interaction 4)

   • If No → Retry Payment (Interaction 5)

6. End

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Diagram Representation (Text format)

pgsqlCopyEdit● (Start)
  |
[Browse Product Catalog]
  |
[Add to Cart]
  |
[Checkout]
  |
◇ [Payment Successful?]
 /         \
Yes         No
/             \
[Send Order]  [Retry Payment]
  |             |
◎ (End)      (loops back to Checkout)

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💡 Explanation of the Flow:

• Each square bracket [ ] represents an interaction reference, typically a sequence diagram.

• The decision node (◇) shows branching based on payment success.

• Arrows represent flow direction.

• Loop can occur if payment fails, by referring back to checkout.

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🚀 Benefits of Interaction Overview Diagrams

Benefit	Explanation
High-Level Process Visualization	Shows how multiple interactions are linked.
Clarifies System Behavior	Breaks down complex workflows into understandable parts.
Improves Communication	Helps stakeholders understand interaction flow easily.
Organizes Interactions	Coordinates many sequence/communication diagrams under one flow.

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🔑 Best Practices for Interaction Overview Diagrams

• Keep interactions concise: Avoid overwhelming with too much detail — link to separate diagrams for specifics.

• Use clear and descriptive labels for interactions.

• Model conditional and parallel flows appropriately to show real system behavior.

• Validate with domain experts and stakeholders to ensure accuracy.

• Use consistent notation across diagrams for clarity.

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🎯 Summary of Interaction Overview Diagrams

Aspect	Details
Purpose	Visualize control flow between multiple interactions
Key Elements	Start, End, Interactions, Decisions, Merges, Forks, Joins, Flows
Main Use Cases	Modeling complex processes, system workflows, interaction coordination
Main Benefit	Simplifies understanding of how multiple interactions fit together

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📚 Relation to Other Diagrams

Diagram Type	Focus
Sequence Diagram	Details of object interactions over time
Activity Diagram	Flow of activities or actions
Interaction Overview Diagram	High-level flow coordinating multiple interactions