Presentation on theme: "Interaction Diagrams CSCI 4320. Interaction Diagrams Two Types of Interaction diagrams defined in UML Collaboration Diagram –Emphasizes the structural."— Presentation transcript:
Interaction Diagrams CSCI 4320
Interaction Diagrams Two Types of Interaction diagrams defined in UML Collaboration Diagram –Emphasizes the structural organization of objects that send and receive messages via the method invocation Sequence Diagram –Emphasizes the time ordering of those messages
Collaboration Diagram Shows the objects as well as the messages that are sent in a specific scenario Objects are arranged to show message passing with a minimum of crossed lines Example: Show a particular Patron object checking out a particular Resource object along with the methods that must be invoked to allow the checking out to occur.
Patron Checking Out Resource ArgoUML
Sequence Diagram Shows the lifeline of when an object is created and activation box of when the object is active. Shows the flow of messages unambiguously Vertical progression from the top of a sequence diagram to the bottom represents the progression of time. Example: Shows the order in which methods must be invoked so that the Patron object can check out the Resource object
Patron Checking Out Resource ArgoUML
Creating Your Sequence Diagram ArgoUML – Collaboration and Sequence features are not active in latest version Use the old version of ArgoUML –This implementation is however not faithful to UML, nor to the look and feel of the rest of ArgoUML Download Version (ZIP file) cumentList?folderID=330 cumentList?folderID=330
Evaluating Design Reasons for modeling software before embarking on writing code –To produced well-structured, modular and correct code requires some planning. –Models allow us to evaluate the quality of the proposed solution without too large an investment of effort. –A sequence diagram that models a scenario may highlight some potential data inconsistencies
Objectives of the Class Design Phase Code Reuse Well-designed Classes and methods Assurance of data integrity
Code Reuse Do any classes intuitively form an inheritance hierarchy? –Software, Book, Resource –Savings, Checking, Account Reuse instead of reinvent mechanisms for interaction –readString(length) used by readTitle() and readArtist() Can classes share methods through a common abstract base class –Both GalleryPainting and AuctionedPainting use getTitle(), getArtist(), getSubject(), getHeight(), getWidth() –Create abstract base class Painting
Well-Designed Classes and Methods Always keep data private Always initialize data in a constructor Do not use too many related primitive types. –Create an aggregate class –Use Address class, rather than several attributes like street, city, zip Not all attributes need individual accessor/mutator ( get/set ) methods Name classes, methods and attributes to be self-documenting
Data Integrity Dirty Data: data that is inaccurate, outdated, or missing Potential vulnerability stems from updating interrelated information in separate transactions or method invocations Interrelated Information –Multiple data values that must be updated together in order to maintain data integrity –Example: When a Patron borrows a Resource both the Patron and the Resource object must be updated with similar information (DueDate) Data integrity is at risk by malicious or inappropriate user access
Things You Should Know Compare and contrast collaboration and sequence diagrams What are ways to support code reuse? What are some rules to follow to create well-defined classes? Describe a situation in which data Integrity can be compromised.