USE CASE DIAGRAM

Hi.. everyone. Hopefully all of u are happy yesterday because we got some knowledge about "use case" diagram. Use case diagram is used to present how a system flow by presented 3 item to show connections in the system. Actually i 'm was interested in learning this diagram because it look simple as long as we know how to find out the 3 items which is: 1)Actor 2)use case and 3)interaction/association. Here i have descriptions of that 3 item.. :)..

Use cases. A use case describes a sequence of actions that provide something of measurable value to an actor and is drawn as a horizontal ellipse.

Actors. An actor is a person, organization, or external system that plays a role in one or more interactions with your system. Actors are drawn as stick figures.

Associations. Associations between actors and use cases are indicated in use case diagrams by solid lines. An association exists whenever an actor is involved with an interaction described by a use case. Associations are modeled as lines connecting use cases and actors to one another, with an optional arrowhead on one end of the line. The arrowhead is often used to indicating the direction of the initial invocation of the relationship or to indicate the primary actor within the use case. The arrowheads are typically confused with data flow and as a result I avoid their use.

System boundary boxes (optional). We can draw a rectangle around the use cases, called the system boundary box, to indicates the scope of your system. Anything within the box represents functionality that is in scope and anything outside the box is not. System boundary boxes are rarely used, although on occasion we have used them to identify which use cases will be delivered in each major release of a system.