ISBN : 978-81-963532-2-3 (E-Book) Fig.b) Representation of BusinessPartner, Customer, Supplier relationship using aggregation • The advantage of aggregation is the integrity of encapsulation. The operations of an object are the interfaces of other objects which imply low implementation dependencies. The significant disadvantage of aggregation is the increase in the number of objects and their relationships. On the other hand, inheritance allows for an easy way to modify implementation for reusability. But the significant disadvantage is that it breaks encapsulation, which implies implementation dependence. ACTIVITYANDSTATECHARTDIAGRAM Theactivitydiagramispossiblyonemodelingelementwhichwasnotpresentinanyofthepredec essors of UML. No such diagrams were present either in the works of Booch, Jacobson, orRumbaugh. It is possibly based on the event diagram of Odell [1992] through the notation is verydifferent from that used by Odell. The activity diagram focuses on representing activities or chunksof processing which may or may not correspond to the methods of classes. An activity is a state withan internal action and one or moreoutgoing transitions which automatically follow the terminationof the internal activity. If an activity has more than one outgoing transitions, then these must beidentified through conditions. An interesting feature of the activity diagrams is the swim lanes. Swimlanes enable you to group activities based on who is performing them, e.g. academic department vs.hostel office. Thus swim lanes subdivide activities based on the responsibilities of some components.Theactivitiesinaswimlanecanbeassignedtosomemodelelements,e.g.classesor somecomponent,etc. Activity diagrams arenormally employed in business process modeling. This is carried out duringthe initial stages of requirements analysis and specification. Activity diagrams can be very useful tounderstand complex processing activities involving many components. Later these diagrams can beusedtodevelopinteractiondiagramswhichhelptoallocateactivities(responsibilities)toclas ses. Thestudentadmissionprocessinauniversityisshownasanactivitydiagraminfig.16.1.Thissho 75 Software Engineering Keerthana P, Manasa KN, Ganga D Bengal
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