Use case is a Unified Modeling Language (UML) technique to capture the requirements in form of a figure. A use case diagram displays relationships between Actors and a Use case. An actor represents a user or another system that will interact with the system. A Use case is the system that we are currently showing. Let us see some Use case diagrams before we actually go through the UML documents.

Figure 2 shows a use case which explains all the operations of a customer from getting a catalogue for ordering and finally getting the confirmation of the same.

Figure 2

Use case document is the supporting document for the use case diagram. It has the description of the use case diagram. It has the following sections.

·         Brief Description – 2 to 3 sentences about the use case

·         Pre-conditions – conditions before the use case actually started

·         Basic flow – the basic control flow

·         Alternative flow – the alternative control flow

·         Post conditions – the condition after the use case executes