Head First Design Patterns

by Freeman, Eric

• ISBN13: 9780596007126
• ISBN10: 0596007124
• Format: Paperback
• Copyright: 2004-11-01
• Publisher: Oreilly & Associates Inc

Summary

Head First Design Patterns introduces software design patterns using the unique and highly effective Head First learning approach made popular in our bestselling Head First Java. This book teaches underlying concepts so that beginner- and intermediate-level developers really understand the implications of applying a particular pattern for application design and performance. They'll learn how patterns are built using Object Oriented design fundamentals, so they can construct their own "elegant" design solutions. Plenty of examples show how design patterns are used.

Author Biography

Eric Freeman is a computer scientist with a passion for media and software architectures and coauthor of Head First Design Patterns. He just wrapped up four years at a dream job-- directing internet broadband and wireless efforts at Disney--and is now back to writing, creating cool software, and hacking Java and Macs. Eric spent a lot of the '90s working on alternatives to the desktop metaphor with David Gelernter (and they're both still asking the question, "Why do I have to give a file a name?"). Based on this work, Eric landed a Ph.D. at Yale University in 1997. He also co-founded Mirror Worlds Technologies (now acquired) to create a commercial version of his thesis work, Lifestreams.

In a previous life, Eric built software for networks and supercomputers. You might know him from such books as JavaSpaces Principles Patterns and Practice. Eric has fond memories of implementing tuple-space systems on Thinking Machine CM-5s and creating some of the first internet information systems for NASA in the late 1980s.

When he's not writing text or code you'll find him spending more time tweaking than watching his home theater and trying to restore a circa 1980s Dragon's Lair video game. He also wouldn't mind moonlighting as an electronica DJ.

Write to him at eric at wickedlysmart dot com or visit him at http://www.ericfreeman.com .

Elisabeth Robson (formerly Freeman) is coauthor of O'Reilly's Head First Design Patterns and Head First HTML with CSS & XHTML. She is currently Special Projects Director at O'Reilly where she is developing new brain-friendly learning ideas and products.

Bert Bates is a 20-year software developer, a Java instructor, and a co-developer of Sun's upcoming EJB exam (Sun Certified Business Component Developer). His background features a long stint in artificial intelligence, with clients like the Weather Channel, A&E Network, Rockwell, and Timken.

Kathy Sierra has been interested in learning theory since her days as a game developer (Virgin, MGM, Amblin'). More recently, she's been a master trainer for Sun Microsystems, teaching Sun's Java instructors how to teach the latest technologies to customers, and a lead developer of several Sun certification exams. Along with her partner Bert Bates, Kathy created the Head First series. She's also the original founder of the Software Development/Jolt Productivity Award-winning javaranch.com, the largest (and friendliest) all-volunteer Java community.

Table of Contents

Intro to Design Patterns
Welcome to Design Patterns: Someone has already solved your problems
The SimUDuck app	p. 2
Joe thinks about inheritance...	p. 5
How about an interface?	p. 6
The one constant in software development	p. 8
Separating what changes from what stays the same	p. 10
Designing the Duck Behaviors	p. 11
Testing the Duck code	p. 18
Setting behavior dynamically	p. 20
The Big Picture on encapsulated behaviors	p. 22
HAS-A can be better than IS-A	p. 23
The Strategy Pattern	p. 24
The power of a shared pattern vocabulary	p. 28
How do I use Design Patterns?	p. 29
Tools for your Design Toolbox	p. 32
Exercise Solutions	p. 34
The Observer Pattern
Keeping your Objects in the Know: Don't miss out when something interesting happens!
The Weather Monitoring application	p. 39
Meet the Observer Pattern	p. 44
Publishers + Subscribers = Observer Pattern	p. 45
Five minute drama: a subject for observation	p. 48
The Observer Pattern defined	p. 51
The power of Loose Coupling	p. 53
Designing the Weather Station	p. 56
Implementing the Weather Station	p. 57
Using Java's built-in Observer Pattern	p. 64
The dark side of java.util. Observable	p. 71
Tools for your Design Toolbox	p. 74
Exercise Solutions	p. 78
The Decorator Pattern
Decorating Objects: Just call this chapter "Design Eye for the Inheritance Guy."
Welcome to Starbuzz Coffee	p. 80
The Open-Closed Principle	p. 86
Meet the Decorator Pattern	p. 88
Constructing a Drink Order with Decorators	p. 89
The Decorator Pattern Defined	p. 91
Decorating our Beverages	p. 92
Writing the Starbuzz code	p. 95
Real World Decorators: Java I/O	p. 100
Writing your own Java I/O Decorator	p. 102
Tools for your Design Toolbox	p. 105
Exercise Solutions	p. 106
The Factory Pattern
Baking with OO Goodness: Get ready to cook some loosely coupled OO designs
When you see "new", think "concrete"	p. 110
Objectville Pizza	p. 112
Encapsulating object creation	p. 114
Building a simple pizza factory	p. 115
The Simple Factory defined	p. 117
A Framework for the pizza store	p. 120
Allowing the subclasses to decide	p. 121
Let's make a PizzaStore	p. 123
Declaring a factory method	p. 125
Meet the Factory Method Pattern	p. 131
Parallel class hierarchies	p. 132
Factory Method Pattern defined	p. 134
A very dependent PizzaStore	p. 137
Looking at object dependencies	p. 138
The Dependency Inversion Principle	p. 139
Meanwhile, back at the PizzaStore...	p. 144
Families of ingredients...	p. 145
Building our ingredient factories	p. 146
Looking at the Abstract Factory	p. 153
Behind the scenes	p. 154
Abstract Factory Pattern defined	p. 156
Factory Method and Abstract Factory compared	p. 160
Tools for your Design Toolbox	p. 162
Exercise Solutions	p. 164
The Singleton Pattern
One of a Kind Objects: The Singleton Pattern: your ticket to creating one-of-a-kind objects, for which there is only one instance
One and only one object	p. 170
The Little Singleton	p. 171
Dissecting the classic Singleton Pattern	p. 173
Confessions of a Singleton	p. 174
The Chocolate Factory	p. 175
Singleton Pattern defined	p. 177
Hershey, PA, we have a problem...	p. 178
BE the JVM	p. 179
Dealing with multithreading	p. 180
Singleton Q&A	p. 184
Tools for your Design Toolbox	p. 186
Exercise Solutions	p. 188
The Command Pattern
Encapsulating Invocation: In this chapter we take encapsulation to a whole new level: we're going to encapsulate method invocation
Home Automation or Bust	p. 192
The Remote Control	p. 193
Taking a look at the vendor classes	p. 194
Meanwhile, back at the Diner...	p. 197
Let's study the Diner interaction	p. 198
The Objectville Diner Roles and Responsibilities	p. 199
From the Diner to the Command Pattern	p. 201
Our first command object	p. 203
The Command Pattern defined	p. 206
The Command Pattern and the Remote Control	p. 208
Implementing the Remote Control	p. 210
Putting the Remote Control through its paces	p. 212
Time to write that documentation	p. 215
Using state to implement Undo	p. 220
Every remote needs a Party Mode!	p. 224
Using a Macro Command	p. 225
More uses of the Command Pattern: Queuing requests	p. 228
More uses of the Command Pattern: Logging requests	p. 229
Tools for your Design Toolbox	p. 230
Exercise Solutions	p. 232
The Adapter and Facade Patterns
Being Adaptive: In this chapter we're going to attempt such impossible feats as putting a square peg in a round hole
Adapters all around us	p. 236
Object Oriented Adapters	p. 237
The Adapter Pattern explained	p. 241
Adapter Pattern defined	p. 243
Object and Class Adapters	p. 244
Tonight's talk: The Object Adapter and Class Adapter	p. 247
Real World Adapters	p. 248
Adapting an Enumeration to an Iterator	p. 249
Tonight's talk: The Decorator Pattern and the Adapter Pattern	p. 252
Home Sweet Home Theater	p. 255
Lights, Camera, Facade!	p. 258
Constructing your Home Theater Facade	p. 261
Facade Pattern defined	p. 264
The Principle of Least Knowledge	p. 265
Tools for your Design Toolbox	p. 270
Exercise Solutions	p. 272
The Template Method Pattern
Encapsulating Algorithms: We've encapsulated object creation, method invocation, complex interfaces, ducks, pizzas...what could be next?
Whipping up some coffee and tea classes	p. 277
Abstracting Coffee and Tea	p. 280
Taking the design further	p. 281
Abstracting prepareRecipe()	p. 282
What have we done?	p. 285
Meet the Template Method	p. 286
Let's make some tea	p. 287
What did the Template Method get us?	p. 288
Template Method Pattern defined	p. 289
Code up close	p. 290
Hooked on Template Method...	p. 292
Using the hook	p. 293
Coffee? Tea? Nah, let's run the TestDrive	p. 294
The Hollywood Principle	p. 296
The Hollywood Principle and the Template Method	p. 297
Template Methods in the Wild	p. 299
Sorting with Template Method	p. 300
We've got some ducks to sort	p. 301
Comparing ducks and ducks	p. 302
The making of the sorting duck machine	p. 304
Swingin' with Frames	p. 306
Applets	p. 307
Tonight's talk: Template Method and Strategy	p. 308
Tools for your Design Toolbox	p. 311
Exercise Solutions	p. 312
The Iterator and Composite Patterns
Well-Managed Collections: There are lots of ways to stuff objects into a collection
Objectville Diner and Pancake House merge	p. 316
Comparing Menu implementations	p. 318
Can we encapsulate the iteration?	p. 323
Meet the Iterator Pattern	p. 325
Adding an Iterator to DinerMenu	p. 326
Looking at the design	p. 331
Cleaning things up with java.util.Iterator	p. 333
What does this get us?	p. 335
Iterator Pattern defined	p. 336
Single Responsibility	p. 339
Iterators and Collections	p. 348
Iterators and Collections in Java 5	p. 349
Just when we thought it was safe...	p. 353
The Composite Pattern defined	p. 356
Designing Menus with Composite	p. 359
Implementing the Composite Menu	p. 362
Flashback to Iterator	p. 368
The Null Iterator	p. 372
The magic of Iterator & Composite together...	p. 374
Tools for your Design Toolbox	p. 380
Exercise Solutions	p. 381
The State Pattern
The State of Things: A little known fact: the Strategy and State Patterns were twins separated at birth
How do we implement state?	p. 387
State Machines 101	p. 388
A first attempt at a state machine	p. 390
You knew it was coming...a change request!	p. 394
The messy STATE of things...	p. 396
Defining the State interfaces and classes	p. 399
Implementing our State Classes	p. 401
Reworking the Gumball Machine	p. 402
The State Pattern defined	p. 410
State versus Strategy	p. 411
State sanity check	p. 417
We almost forgot!	p. 420
Tools for your Design Toolbox	p. 423
Exercise Solutions	p. 424
The Proxy Pattern
Controlling Object Access: Every play good cop, bad cop?
Monitoring the gumball machines	p. 430
The role of the 'remote proxy'	p. 434
RMI detour	p. 437
GumballMachine remote proxy	p. 450
Remote proxy behind the scenes	p. 458
The Proxy Pattern defined	p. 460
Get Ready for virtual proxy	p. 462
Designing the CD cover virtual proxy	p. 464
Virtual proxy behind the scenes	p. 470
Using the Java API's proxy	p. 474
Five minute drama: protecting subjects	p. 478
Creating a dynamic proxy	p. 479
The Proxy Zoo	p. 488
Tools for your Design Toolbox	p. 491
Exercise Solutions	p. 492
Compound Patterns
Patterns of Patterns: Who would have ever guessed that Patterns could work together?
Compound Patterns	p. 500
Duck reunion	p. 501
Adding an adapter	p. 504
Adding a decorator	p. 506
Adding a factory	p. 508
Adding a composite, and iterator	p. 513
Adding an observer	p. 516
Patterns summary	p. 523
A duck's eye view: the class diagram	p. 524
Model-View-Controller, the song	p. 526
Design Patterns are your key to the MVC	p. 528
Looking at MVC through patterns-colored glasses	p. 532
Using MVC to control the beat...	p. 534
The Model	p. 537
The View	p. 539
The Controller	p. 542
Exploring strategy	p. 545
Adapting the model	p. 546
Now we're ready for a HeartController	p. 547
MVC and the Web	p. 549
Design Patterns and Model 2	p. 557
Tools for your Design Toolbox	p. 560
Exercise Solutions	p. 561
Better Living with Patterns
Patterns in the Real World: Ahhhh, now you're ready for a bright new world filled with Design Patterns
Your Objectville guide	p. 578
Design Pattern defined	p. 579
Looking more closely at the Design Pattern definition	p. 581
May the force be with you	p. 582
Pattern catalogs	p. 583
How to create patterns	p. 586
So you wanna be a Design Patterns writer?	p. 587
Organizing Design Patterns	p. 589
Thinking in patterns	p. 594
Your mind on patterns	p. 597
Don't forget the power of the shared vocabulary	p. 599
Top five ways to share your vocabulary	p. 600
Cruisin' Objectville with the Gang of Four	p. 601
Your journey has just begun...	p. 602
Other Design Pattern resources	p. 603
The Patterns Zoo	p. 604
Annihilating evil with Anti-Patterns	p. 606
Tools for your Design Toolbox	p. 608
Leaving Objectville...	p. 609
Appendix: Leftover Patterns: Not everyone can be the most popular
Bridge	p. 612
Builder	p. 614
Chain of Responsibility	p. 616
Flyweight	p. 618
Interpreter	p. 620
Mediator	p. 622
Memento	p. 624
Prototype	p. 626
Visitor	p. 628
Index	p. 631
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