? ??Module 5 Interaction DiagramsTopicsObjectivesObjects Need to CollaborateObjects Interact with MessagesWhat is an Interaction Diagram?Interaction DiagramsInteraction DiagramsWhere Are We?What Is a Sequence Diagram?Example: Sequence DiagramSequence Diagram Contents: ObjectsSequence Diagram Contents: ActorSequence Diagram Contents: MessagesSequence Diagram Contents: Execution OccurrenceSequence Diagram Contents: Event OccurrenceSequence Diagram Contents: Interaction OccurrenceWhere Are We?What Is a Communication Diagram?Example: Communication DiagramCommunication Diagrams Contents: ObjectsCommunication Diagram Contents: ActorsCommunication Diagram Contents: Links and MessagesWhere Are We?Sequence and Communication Diagram SimilaritiesSequence and Communication Diagram DifferencesReviewExercise► ► ► Module 5 Interaction Diagrams 1IBM Software Group®Essentials of Visual Modeling with UML 2.0Module 5: Interaction Diagrams Topics What is an Interaction Diagram?........................................................................... 5-5 What Is a Sequence Diagram? .............................................................................. 5-9 What Is a Communication Diagram?................................................................... 5-18 Sequence and Communication Diagram Similarities ........................................... 5-24 © Copyright IBM Corp. 2004 5 - 1 Course materials may not be reproduced in whole or in part without the prior written permission of IBM.Essentials of Visual Modeling with UML 2.0 Objectives 2Objectives Describe dynamic behavior and show how to capture it in a model. Demonstrate how to read and interpret:  A sequence diagram  A communication diagram Explain the similarities and differences between communication and sequence diagrams. 5 - 2 © Copyright IBM Corp. 2004 Course materials may not be reproduced in whole or in part without the prior written permission of IBM.Module 5 - Interaction Diagrams Objects Need to Collaborate 3Objects Need to Collaborate Objects are useless unless they can collaborate to solve a problem. Each object is responsible for its own behavior and status. No one object can carry out every responsibility on its own. How do objects interact with each other? They interact through messages. Objects need to realize the behavior specified in each use-case scenario. How is this done? The objects must collaborate together to bring about the desired behavior in the system. Is there a mechanism that allows these objects to work together? There is, and that mechanism is called a message. © Copyright IBM Corp. 2004 5 - 3 Course materials may not be reproduced in whole or in part without the prior written permission of IBM.Essentials of Visual Modeling with UML 2.0 Objects Interact with Messages 4Objects Interact with Messages A message shows how one object asks another object to perform some activity.: Car buyer:RegistrationController :CourseCatalogSystemgetCourseOfferings(forSemester)Message A message can be defined as: The specification of a communication among objects that conveys information with the expectation that activity will ensue. (The Unified Modeling Language User Guide, Booch, 1999.) • When you pass a message, the action that results is an executable statement that forms an abstraction of a computational procedure. An action may result in a change of state. • Messages are the mechanism that permits objects to interact with each other. A message is often implemented by a simple activity. For example, one object calls an operation in another. When the activity has been executed, the control is returned to the caller along with a return value. 5 - 4 © Copyright IBM Corp. 2004 Course materials may not be reproduced in whole or in part without the prior written permission of IBM.Module 5 - Interaction Diagrams What is an Interaction Diagram? 5What is an Interaction Diagram? Generic term that applies to several diagrams that emphasize object interactions Sequence Diagram Communication Diagram Specialized Variants Timing Diagram Interaction Overview Diagram © Copyright IBM Corp. 2004 5 - 5 Course materials may not be reproduced in whole or in part without the prior written permission of IBM.Essentials of Visual Modeling with UML 2.0 Interaction Diagrams 6Interaction Diagrams Sequence Diagram Time oriented view of object interaction  Communication Diagram Structural view of messaging objectsCommunication DiagramsSequence Diagrams The sequence diagram is a time-oriented view of the interaction between objects to accomplish a behavioral goal of the system. An interaction may be modeled at any level of abstraction within the system design, from subsystem interactions to instance-level interaction for a single operation or activity. The communication diagram is a structural view of the messaging between objects, taken from the Collaboration diagram concept of UML1. 5 - 6 © Copyright IBM Corp. 2004 Course materials may not be reproduced in whole or in part without the prior written permission of IBM.Module 5 - Interaction Diagrams Interaction Diagrams 7Interaction Diagrams Timing Diagram Time constraint view of messages involved in an interaction Interaction Overview Diagram High level view of interaction sets combined into logic sequenceTiming DiagramsInteraction Overview Diagrams The timing diagram is an optional diagram designed to specify the time constraints on messages sent and received in the course of an interaction. This diagram probably has more usefulness in real-time applications where timing is critical. The interaction overview diagram is a high-level view of the sets of interactions combined into logic sequence, including flow-control logic to navigate between the interactions. Think of this as a cross between a Sequence Diagram, for the interactions sets, and an Activity Diagram, for the logic sequence. © Copyright IBM Corp. 2004 5 - 7 Course materials may not be reproduced in whole or in part without the prior written permission of IBM.Essentials of Visual Modeling with UML 2.0 Where Are We? 8 Sequence diagrams Communication diagrams Interaction diagram comparisonWhere Are We? 5 - 8 © Copyright IBM Corp. 2004 Course materials may not be reproduced in whole or in part without the prior written permission of IBM.Module 5 -