Book Image

UML 2.0 in Action: A project-based tutorial

Book Image

UML 2.0 in Action: A project-based tutorial

Overview of this book

Most books about UML describe it almost in its entirety. Inevitably you're left with only a superficial knowledge of the range of UML elements, without a deep and intuitive understanding of how to apply UML as a whole to real world design problems. This book doesn't set out to cover all of UML, but instead pulls together those parts of UML with immediate practical relevance and presents them as part of a coherent process for using UML in your actual development projects.This book is designed to be read while you work on a real project. After an initial review of the essentials of UML and the design process, it begins with the modeling of a business system and its business processes, in this case an airport. Then the IT system intended to serve that business process is described and analysed. Finally the integration of the system into the production environment is covered in detail. The book can be used in two ways: it can be read through as a thorough grounding in how UML really works in practice; in addition it can be used as stand alone guide to that particular aspect of your own project. Both result in an intuitive understanding of how to actually use UML.
Table of Contents (11 chapters)

5.2 Messages in UML

In the UML sequence diagram, messages are illustrated with an arrow symbol, together with the name of the message and its parameters (if present). In this way, in UML a message is categorically divided into two parts:

  • The name of the message specifies the event.

  • The arguments of the message contain the information that is attached to the message, so that the receiver can perform the necessary activities. Control information belongs in this category as well.

We refer to the information that is exchanged as a business object, if the information:

  • Is coherent

  • Is structured

  • Covers the requirements for a certain activity (e.g., invoice, passenger list)

  • Is self-contained (no in-house reference keys, etc.)

  • Outlives individual interactions

In the UML model of system integration, business objects are structured information sent as arguments in a message from a sender to a receiver.