Activity Diagrams and UP Activity Diagram Principle and Application Activity diagrams use the Petri net formalism to represent various flows, their timing and order ADs are used to model dynamic behavior or Operations ADs are used for Use Cases, Classes, Interfaces, Components, Collaborations, OperationsSee next slideMore UML diagrams for data flowsFor modeling and software design activity diagrams are also used, butThere are more appropriate diagrams for software modelingSequence and communication diagramsIt is better to use themSome anomalies of NODES and EDGESUcases and activity diagramsADs is for PROCESS butUseCase is NOT a processIt is a DIALOGUE (see 1C) or a CONVERSATIONA group of messagesWe need a symbolUseCase needs a dialogue symbol NOT an announcementWe used an oval with a message groupBPMN uses a HEXEXPANDS into a message groupSome interactions ARE dialogs UseCASEWhen a subtitle -the process involves only a single computer and a single user. The messages between them constitute a use case dialogue. One difference is that in a use case the focus is on the exchanging messages but NOT on the internal activities of the user or the system that flows and transforms. To be precise, Tokens DO NOT flow through nodes They flow through edges They are transformed into nodes Electronic Payment: a complex PROCESS Involves FOUR entities that are all systems. Each system can be a system under investigation and have its own use case diagram that is different from those of other systems. You need to start with the PROCESS activity diagram and then proceed to modeling the use cases for each system separately. Independently analyze and integrate. The complexity of the main process is not overlooked but each sub-process is... in the center of the paper... etc. streamsStream lines are of the same TYPEWhat flows in,The NODE,What comes out,Are also the sameInconsistencies of object node and streamsThe input and output edges of "object nodes" are "object streams". These are special types of flows that represent the movement of objects shown as nodes. The objects themselves are created and consumed by NORMAL action nodes. Object flows in the BPMN convention 1 Flow of controls, messages and objects are very distinctThe "order" flows of objects from A1 to A2Along the dotted line (non-physical path)The object is shown ON the dotted path but is NOT a NODEIt is not an elegant notation.The object flows in BPMN convention 2Here the control flow is from A1 to A2And the object flow is also from A1 to A2So, the object is "bound" to the control flow (as in UML's binding class) This is much simpler and reduces conflicts. It also requires less space.