ooad1-2  Exercise 2: A PlantUML Use Case Diagram
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borrow.usecase.puml (PlantUML 1.2026.8):

  @startuml
  scale 1.5
  left to right direction
  actor Member
  actor Librarian

  rectangle "Library system" {
    usecase "Borrow a book" as UC1
    usecase "Return a book" as UC2
    usecase "Pay a fine" as UC3
  }

  Member --> UC1
  Member --> UC2
  Member --> UC3
  Librarian --> UC1
  Librarian --> UC2
  @enduml

Render and output:

  $ py render_diagrams.py ex2
  rendered    ex2\borrow.usecase.puml  ->  borrow.usecase.puml.svg  (5 KB)

What you should see: two stick figures (Member, Librarian) on the left, a box labelled "Library system" containing three ellipses, and lines from each actor to the use cases they take part in. Member connects to all three; Librarian to Borrow and Return only.

WHY THIS WORKS AS AN ANSWER
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The rectangle is the system boundary: everything inside is what the system does; the actors stand outside because they are not part of it. "left to right direction" keeps the actors beside the boundary instead of above it. Note a modelling choice worth questioning in chapter 3: the Librarian borrowing "on a member's behalf" is drawn as the Librarian taking part in the same use case, which hides that the goal belongs to the member. Chapter 3 discusses how to show that.