1 getting organized 1 - jones & bartlett...

1 Getting Organized 11.1 Software Engineering 2

Software Life Cycles 3Agile Methods 5Goals of Quality Software 6

1.2 Object Orientation 8The Unified Method 8

1.3 Classes, Objects, and Applications 9Classes 9Objects 16Applications 17

1.4 Organizing Classes 20Inheritance 20Packages 25

1.5 Data Structures 28Implementation-Dependent Structures 29Implementation-Independent Structures 30What Is a Data Structure? 33

1.6 Basic Structuring Mechanisms 33References 33Arrays 38

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1.7 Comparing Algorithms: Big-O Analysis 41Big-O Notation 43Common Orders of Magnitude 45Example 1: Sum of Consecutive Integers 46Example 2: Finding a Number in a Phone Book 48

Summary 50Exercises 51

2 Abstract Data Types 632.1 Abstraction 64

Information Hiding 64Data Abstraction 65Data Levels 66Preconditions and Postconditions 67Java Interfaces 68

2.2 The StringLog ADT Specification 72Constructors 72Transformers 73Observers 73The StringLogInterface 73Using the StringLogInterface 75

2.3 Array-Based StringLog ADT Implementation 77Instance Variables 77Constructors 79Transformers 80Observers 82

2.4 Software Testing 91Identifying Test Cases 92Test Plans 94Testing ADT Implementations 94

2.5 Introduction to Linked Lists 102Array Versus Linked Lists 102The LLStringNode Class 103Operations on Linked Lists 107

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2.6 Linked List StringLog ADT Implementation 113Instance Variables 115Constructors 115Transformers 116Observers 119

2.7 Software Design: Identification of Classes 124Brainstorm 124Filter 125Scenario Analysis 125Nouns and Verbs 125Cohesive Designs 126Summation of Our Approach 126Design Choices 128

2.8 Case Study: A Trivia Game 128The Source of the Trivia Game 129Identifying Support Classes 131Implementing the Support Classes 133The Trivia Game Application 140Case Study Summation 145


3 The Stack ADT 1593.1 Stacks 160

Operations on Stacks 161Using Stacks 161

3.2 Collection Elements 163Generally Usable Collections 164

3.3 Exceptional Situations 167Handling Exceptional Situations 167Exceptions and ADTs: An Example 168Error Situations and ADTs 173

3.4 Formal Specification 175Exceptional Situations 176The Interfaces 179Example Use 182

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3.5 Array-Based Implementations 185The ArrayStack Class 185Definitions of Stack Operations 188Test Plan 190

3.6 Application: Well-Formed Expressions 194The Balanced Class 194The Application 200

3.7 Link-Based Implementation 202The LLObject Node Class 203The LinkedStack Class 204The push Operation 205The pop Operation 209The Other Stack Operations 211Comparing Stack Implementations 213

3.8 Case Study: Postfix Expression Evaluator 214Discussion 214Evaluating Postfix Expressions 215Postfix Expression Evaluation Algorithm 216Specification: Program Postfix Evaluation 219Brainstorming and Filtering 220The PostFixEvaluator Class 222The PFixConsole Class 224Testing the Postfix Evaluator 226


4 Recursion 2434.1 Recursive Definitions, Algorithms, and Programs 244

Recursive Definitions 244Recursive Algorithms 245Recursive Programs 248

4.2 The Three Questions 251Verifying Recursive Algorithms 251Writing Recursive Methods 253Debugging Recursive Methods 253

4.3 Towers of Hanoi 254The Algorithm 254

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The Method 256The Program 257

4.4 Counting Blobs 260Generating Blobs 261The Counting Algorithm 262The Marking Algorithm 263The Grid Class 264The Program 267

4.5 Recursive Linked-List Processing 269Reverse Printing 269

4.6 Removing Recursion 273How Recursion Works 274Iteration 278Stacking 279

4.7 Deciding Whether to Use a Recursive Solution 281Recursion Overhead 282Inefficient Algorithms 282Clarity 285


5 The Queue ADT 2975.1 Queues 298

Operations on the Queues 299Using Queues 299

5.2 Formal Specification 300Example Use 303

5.3 Array-Based Implementations 305The ArrayBndQueue Class 305The ArrayUnbndQueue Class 312

5.4 Application: Palindromes 315The Palindrome Class 316The Application 318

5.5 Application: The Card Game of War 321The RankCardDeck Class 321The WarGame Class 323The WarGameApp Class 327

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5.6 Link-Based Implementations 331The Enqueue Operation 332The Dequeue Operation 334The Queue Implementation 336A Circular Linked Queue Design 337Comparing Queue Implementations 338

5.7 Concurrency, Interference, and Synchronization 340The counter Class 340Java Threads 342Interference 345Synchronization 346A Synchronized Queue 348

5.8 Case Study: Average Waiting Time 353Problem Discussion 354Program Design 356Program Details 360Testing Considerations 369


6 The List ADT 3836.1 Comparing Objects Revisited 384

The equals Method 384The Comparable Interface 386

6.2 Lists 388Varieties of Lists 389Assumptions for Our Lists 389

6.3 Formal Specification 390The ListInterface 390The Indexed List Interface 393Example Use 394

6.4 Array-Based Implementations 397The ArrayUnsortedList Class 398The ArraySortedList Class 403The ArrayIndexedList Class 411

6.5 Applications: Poker, Golf, and Music 414Poker 414

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Golf 418Music 421

6.6 The Binary Search Algorithm 425Improving Linear Search in a Sorted List 426Binary Search Algorithm 426Recursive Binary Search 431Efficiency Analysis 432

6.7 Reference-Based Implementations 433The RefUnsortedList Class 434The RefSortedList Class 440

6.8 Storing Objects and Structures in Files 445Saving Object Data in Text Files 445Serialization of Objects 447Serializing Structures 450Application: Song Lists 451


7 More Lists 4737.1 Circular Linked Lists 474

An Unsorted Circular List 475The CRefUnsortedList Class 476Circular Versus Linear Linked Lists 482

7.2 Doubly Linked Lists 483The Add and Remove Operations 484

7.3 Linked Lists with Headers and Trailers 4877.4 A Linked List as an Array of Nodes 488

Why Use an Array? 488How Is an Array Used? 489

7.5 A Specialized List ADT 497The Specification 498The Implementation 499

7.6 Case Study: Large Integers 504The LargeInt Class 508Addition and Subtraction 510

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Test Plan 519The LargeIntApp Program 519


8 Binary Search Trees 5318.1 Trees 532

Binary Trees 534Binary Search Trees 536Binary Tree Traversals 538

8.2 The Logical Level 540Tree Elements 540The Binary Search Tree Specification 541

8.3 The Application Level 5438.4 The Implementation Level: Basics 5458.5 Iterative Versus Recursive Method Implementations 548

Recursive Approach to the size Method 549Iterative Approach to the size Method 553Recursion or Iteration? 555

8.6 The Implementation Level: Remaining Operations 555The contains and get Operations 555The add Operation 559The remove Operation 564Iteration 571Testing Binary Search Tree Operations 575

8.7 Comparing Binary Search Tree and Linear Lists 577Big-O Comparisons 577

8.8 Balancing a Binary Search Tree 5788.9 A Nonlinked Representation of Binary Trees 5848.10 Case Study: Word Frequency Generator 588

Problem 588Discussion 588Brainstorming 588Filtering 589The User Interface 589Error Handling 590Scenario Analysis 590

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The WordFreq Class 592The Word Frequency Generator Program 594Testing 596


9 Priority Queues, Heaps, and Graphs 6139.1 Priority Queues 614

Logical Level 614Application Level 616Implementation Level 616

9.2 Heaps 617Heap Implementation 621The enqueue Method 623The dequeue Method 626A Sample Use 630Heaps Versus Other Representations of Priority Queues 632

9.3 Introduction to Graphs 6339.4 Formal Specification of a Graph ADT 6379.5 Implementations of Graphs 640

Array-Based Implementation 640Linked Implementation 645

9.6 Graph Applications 646Depth-First Searching 647Breadth-First Searching 651The Single-Source Shortest-Paths Problem 654


10 Sorting and Searching Algorithms 67110.1 Sorting 672

A Test Harness 67310.2 Simple Sorts 676

Straight Selection Sort 676Bubble Sort 682Insertion Sort 686

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10.3 O(N log2N) Sorts 690Merge Sort 690Quick Sort 698Heap Sort 704

10.4 More Sorting Considerations 710Testing 710Efficiency 710Objects and References 712Using the Comparable Interface 712Using the Comparator Interface 713Stability 719

10.5 Searching 720Linear Searching 720High Probability Ordering 721Sorted Lists 722

10.6 Hashing 722Collisions 726Choosing a Good Hash Function 734Complexity 737


Appendix A Java Reserved Words 749Appendix B Operator Precedence 750Appendix C Primitive Data Types 751Appendix D ASCII Subset of Unicode 752Appendix E Application of Programmer Interfaces for the

Java Classes and Interfaces Used in This Book 753

Index 769

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