Dr. Dobb's Journal - July 2008 - (Page 33)

8 public PurchasableItem (String label, float cost, String manufacturer) { // Call appropriate setters 13 } // Typical getters and setters follow 35 } Person -name +getName() +setName() Transaction -buyer : Person -seller : Person -containsItem : PurchasableItem -sellDate -shipDate -label +getBuyer() +setBuyer() +getContainsItem() +setContainsItem() +getSellDate() +setSellDate() +getShipDate() +setShipDate() +getLabel() +setLabel() PurchasableItem -name -cost -manufacturer -label +getCost() +setCost() +getManufacturer() +setManufacturer() +getLabel() +setLabel() Add a Transaction class and we’re ready to open our doors: 3 public class Transaction { 7 private Person buyer, seller; 8 private PurchasableItem containsItem; 9 private Date sellDate, shipDate; 10 private String label; 12 public Transaction(Person buyer, Person seller, PurchasableItem containsItem, Date sellDate, Date shipDate) { 13 super(); 14 setBuyer(buyer); // Call appropriate setters // with remaining parameters 19 } 59 } Let’s watch our first sale happen as we create instances provided by the class definitions. (The full code is online.) //Matt Person seller = new Person("Matt Fisher"); // is selling his special toaster PurchasableItem toaster = new PurchasableItem("High-wolf shiny toaster", (float)49.95, "Dualit"); pItems.add(toaster); // pItems is a HashSet of PurchasableItems // John Person buyer = new Person("John Hebeler"); // is buying the toaster very soon! Figure 1: UML class diagram. Calendar sellDateCalendar = Calendar.getInstance(); sellDateCalendar.set(2008, 3, 24, 10, 0, 0); Date sellDate = sellDateCalendar.getTime(); // similar code follows for shipDate Transaction tran = new Transaction(buyer, seller, toaster, sellDate, shipDate); transactions.add(tran); Keeping track of our marketplace requires some custom queries that interrogate our objects: Get moving. Stay focused. Take control. Enterprise Architect from Sparx Systems redefines visual modeling with a huge set of built-in tools, technologies and capabilities, coupled with a lightweight footprint and great agility. With deep support for UML 2.1 and its related standards, Enterprise Architect 7.1 is the ideal tool to analyze, design, build and manage your next software project. Keep your project moving, keep your team focused and stay in total control. Visit sparxsystems.com for a free trial July 2008 l www.ddj.com l Dr. Dobb’s Journal 33 http://sparxsystems.com http://sparxsystems.com http://www.ddj.com

Table of Contents Feed for the Digital Edition of Dr. Dobb's Journal - July 2008

Dr. Dobb's Journal - July 2008 Contents Friday Night Fish Fry Alia Vox Developer Diaries Developer’s Notebook Engineers Without Borders Conversations Patricia Tries Event-Based Architectures Graphs Versus Objects Lock-Free Queues Dr. Dobb’s Architecture & Design World Java and the Nokia N10 Internet Tablet Effective Concurrency The Agile Edge Swaine’s Flames

Dr. Dobb's Journal - July 2008

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