Brief Java

Preface v


Special Features xxvi


1 Introduction 1


1.1 Computer Programs 2


1.2 The Anatomy of a Computer 3


1.3 The Java Programming Language 5


1.4 Becoming Familiar with Your Programming Environment 7


1.5 Analyzing Your First Program 11


1.6 Errors 13


1.7 PROBLEM SOLVING Algorithm Design 15


The Algorithm Concept 15


An Algorithm for Solving an Investment Problem 16


Pseudocode 17


From Algorithms to Programs 18


HT 1 Describing an Algorithm with Pseudocode 18


WE 1 Writing an Algorithm for Tiling a Floor 20


2 Using Objects 23


2.1 Objects and Classes 24


Using Objects 24


Classes 25


2.2 Variables 26


Variable Declarations 26


Types 28


Names 29


Comments 30


Assignment 30


ST 1 Variable Type Inference 33


2.3 Calling Methods 33


The Public Interface of a Class 33


Method Arguments 34


Return Values 35


Method Declarations 36


2.4 Constructing Objects 38


2.5 Accessor and Mutator Methods 40


2.6 The API Documentation 41


Browsing the API Documentation 41


Packages 43


2.7 Implementing a Test Program 44


ST 2 Testing Classes in an Interactive Environment 45


WE 1 How Many Days Have You Been Alive? 46


WE 2 Working with Pictures 46


2.8 Object References 46


2.9 Graphical Applications 49


Frame Windows 50


Drawing on a Component 51


Displaying a Component in a Frame 53


2.10 Ellipses, Lines, Text, and Color 54


Ellipses and Circles 54


Lines 55


Drawing Text 56


Colors 56


3 Implementing Classes 61


3.1 Instance Variables and Encapsulation 62


Instance Variables 62


The Methods of the Counter Class 64


Encapsulation 64


3.2 Specifying the Public Interface of a Class 66


Specifying Methods 66


Specifying Constructors 67


Using the Public Interface 69


Commenting the Public Interface 69


3.3 Providing the Class Implementation 72


Providing Instance Variables 72


Providing Constructors 73


Providing Methods 75


HT 1 Implementing a Class 78


WE 1 Making a Simple Menu 81


3.4 Unit Testing 81


3.5 PROBLEM SOLVING Tracing Objects 84


3.6 Local Variables 86


3.7 The this Reference 88


ST 1 Calling One Constructor from Another 90


3.8 Shape Classes 90


HT 2 Drawing Graphical Shapes 94


4 Fundamental Data Types 99


4.1 Numbers 100


Number Types 100


Constants 102


ST 1 Big Numbers 106


4.2 Arithmetic 107


Arithmetic Operators 107


Increment and Decrement 107


Integer Division and Remainder 108


Powers and Roots 109


Converting Floating-Point Numbers to Integers 110


ST 2 Avoiding Negative Remainders 112


ST 3 Combining Assignment and Arithmetic 113


ST 4 Instance Methods and Static Methods 113


4.3 Input and Output 114


Reading Input 114


Formatted Output 115


HT 1 Carrying Out Computations 118


WE 1 Computing the Volume and Surface Area of a Pyramid 121


4.4 PROBLEM SOLVING First Do it By Hand 121


WE 2 Computing Travel Time 122


4.5 Strings 122


The String Type 122


Concatenation 123


String Input 124


Escape Sequences 124


Strings and Characters 124


Substrings 125


ST 5 Using Dialog Boxes for Input and Output 128


5 Decisions 131


5.1 The if Statement 132


ST 1 The Conditional Operator 137


5.2 Comparing Values 137


Relational Operators 138


Comparing Floating-Point Numbers 139


Comparing Strings 140


Comparing Objects 141


Testing for null 141


HT 1 Implementing an if Statement 143


WE 1 Extracting the Middle 146


5.3 Multiple Alternatives 146


ST 2 The switch Statement 148


5.4 Nested Branches 149


ST 3 Block Scope 154


ST 4 Enumeration Types 155


5.5 PROBLEM SOLVING Flowcharts 156


5.6 PROBLEM SOLVING Selecting Test Cases 159


ST 5 Logging 161


5.7 Boolean Variables and Operators 161


ST 6 Short-Circuit Evaluation of Boolean Operators 165


ST 7 De Morgan’s Law 165


5.8 APPLICATION Input Validation 166


6 Loops 171


6.1 The while Loop 172


6.2 PROBLEM SOLVING Hand-Tracing 179


6.3 The for Loop 183


ST 1 Variables Declared in a for Loop Header 189


6.4 The do Loop 190


6.5 APPLICATION Processing Sentinel Values 192


ST 2 Redirection of Input and Output 194


ST 3 The “Loop and a Half” Problem 194


ST 4 The break and continue Statements 195


6.6 PROBLEM SOLVING Storyboards 197


6.7 Common Loop Algorithms 199


Sum and Average Value 199


Counting Matches 200


Finding the First Match 200


Prompting Until a Match is Found 201


Maximum and Minimum 201


Comparing Adjacent Values 202


HT 1 Writing a Loop 203


WE 1 Credit Card Processing 206


6.8 Nested Loops 206


WE 2 Manipulating the Pixels in an Image 209


6.9 APPLICATION Random Numbers and Simulations 209


Generating Random Numbers 210


The Monte Carlo Method 211


6.10 Using a Debugger 213


HT 2 Debugging 215


WE 3 A Sample Debugging Session 217


7 Arrays and Array Lists 221


7.1 Arrays 222


Declaring and Using Arrays 222


Array References 225


Using Arrays with Methods 226


Partially Filled Arrays 226


ST 1 Methods with a Variable Number of Arguments 229


7.2 The Enhanced for Loop 230


7.3 Common Array Algorithms 232


Filling 232


Sum and Average Value 232


Maximum and Minimum 232


Element Separators 232


Linear Search 233


Removing an Element 234


Inserting an Element 234


Swapping Elements 236


Copying Arrays 237


Reading Input 238


ST 2 Sorting with the Java Library 240


7.4 PROBLEM SOLVING Adapting Algorithms 240


HT 1 Working with Arrays 242


WE 1 Rolling the Dice 245


7.5 PROBLEM SOLVING Discovering Algorithms by Manipulating Physical Objects 245


7.6 Two-Dimensional Arrays 248


Declaring Two-Dimensional Arrays 248


Accessing Elements 249


Locating Neighboring Elements 250


Accessing Rows and Columns 251


Two-Dimensional Array Parameters 252


WE 2 A World Population Table 253


ST 3 Two-Dimensional Arrays with Variable Row Lengths 254


ST 4 Multidimensional Arrays 255


7.7 Array Lists 255


Declaring and Using Array Lists 255


Using the Enhanced for Loop with Array Lists 258


Copying Array Lists 259


Wrappers and Auto-boxing 259


Using Array Algorithms with Array Lists 260


Storing Input Values in an Array List 261


Removing Matches 261


Choosing Between Array Lists and Arrays 262


ST 5 The Diamond Syntax 264


7.8 Regression Testing 264


8 Designing Classes 271


8.1 Discovering Classes 272


8.2 Designing Good Methods 273


Providing a Cohesive Public Interface 273


Minimizing Dependencies 274


Separating Accessors and Mutators 275


Minimizing Side Effects 276


ST 1 Call by Value and Call by Reference 278


8.3 PROBLEM SOLVING Patterns for Object Data 282


Keeping a Total 282


Counting Events 283


Collecting Values 283


Managing Properties of an Object 284


Modeling Objects with Distinct States 284


Describing the Position of an Object 285


8.4 Static Variables and Methods 286


ST 2 Alternative Forms of Instance and Static Variable Initialization 289


ST 3 Static Imports 290


8.5 PROBLEM SOLVING Solve a Simpler Problem First 291


8.6 Packages 295


Organizing Related Classes into Packages 295


Importing Packages 296


Package Names 297


Packages and Source Files 297


ST 4 Package Access 298


HT 1 Programming with Packages 299


8.7 Unit Test Frameworks 300


Inheritance 305


9.1 Inheritance Hierarchies 306


9.2 Implementing Subclasses 310


9.3 Overriding Methods 314


ST 1 Calling the Superclass Constructor 318


9.4 Polymorphism 319


ST 2 Dynamic Method Lookup and the Implicit Parameter 322


ST 3 Abstract Classes 323


ST 4 Final Methods and Classes 324


ST 5 Protected Access 324


HT 1 Developing an Inheritance Hierarchy 325


WE 1 Implementing an Employee Hierarchy for Payroll Processing 330


9.5 Object: The Cosmic Superclass 330


Overriding the toString Method 330


The equals Method 332


The instanceof Operator 333


ST 6 Inheritance and the toString Method 335


ST 7 Inheritance and the equals Method 336


10 Interfaces 339


10.1 Using Interfaces for Algorithm Reuse 340


Discovering an Interface Type 340


Declaring an Interface Type 341


Implementing an Interface Type 343


Comparing Interfaces and Inheritance 345


ST 1 Constants in Interfaces 346


ST 2 Nonabstract Interface Methods 347


10.2 Working with Interface Variables 348


Converting from Classes to Interfaces 348


Invoking Methods on Interface Variables 349


Casting from Interfaces to Classes 349


WE 1 Investigating Number Sequences 350


10.3 The Comparable Interface 350


ST 3 The clone Method and the Cloneable Interface 352


10.4 Using Interfaces for Callbacks 355


ST 4 Lambda Expressions 358


ST 5 Generic Interface Types 360


10.5 Inner Classes 360


10.6 Mock Objects 361


10.7 Event Handling 363


Listening to Events 363


Using Inner Classes for Listeners 365


10.8 Building Applications with Buttons 368


10.9 Processing Timer Events 371


10.10 Mouse Events 374


ST 6 Keyboard Events 377


ST 7 Event Adapters 378


11 Input/Output and Exception Handling 383


11.1 Reading and Writing Text Files 384


ST 1 Reading Web Pages 387


ST 2 File Dialog Boxes 387


ST 3 Character Encodings 388


11.2 Text Input and Output 389


Reading Words 389


Reading Characters 390


Classifying Characters 390


Reading Lines 390


Scanning a String 392


Converting Strings to Numbers 392


Avoiding Errors When Reading Numbers 392


Mixing Number, Word, and Line Input 393


Formatting Output 394


ST 4 Regular Expressions 395


ST 5 Reading an Entire File 396


11.3 Command Line Arguments 396


HT 1 Processing Text Files 399


WE 1 Analyzing Baby Names 403


11.4 Exception Handling 403


Throwing Exceptions 403


Catching Exceptions 405


Checked Exceptions 407


Closing Resources 409


Designing Your Own Exception Types 410


ST 6 Assertions 411


ST 7 The try/finally Statement 412


11.5 APPLICATION Handling Input Errors 412


12 Object-Oriented Design 419


12.1 Classes and Their Responsibilities 420


Discovering Classes 420


The CRC Card Method 421


12.2 Relationships Between Classes 423


Dependency 423


Aggregation 424


Inheritance 425


HT 1 Using CRC Cards and UML Diagrams in Program Design 426


ST 1 Attributes and Methods in UML Diagrams 426


ST 2 Multiplicities 427


ST 3 Aggregation, Association, and Composition 427


12.3 APPLICATION Printing an Invoice 428


Requirements 429


CRC Cards 429


UML Diagrams 432


Method Documentation 432


Implementation 434


WE 1 Simulating an Automatic Teller Machine 439


13 Recursion* (Etext Only) 443


13.1 Triangle Numbers 444


HT 1 Thinking Recursively 448


WE 1 Finding Files 452


13.2 Recursive Helper Methods 452


13.3 The Efficiency of Recursion 453


13.4 Permutations 459


13.5 Mutual Recursion 463


13.6 Backtracking 469


WE 2 Towers of Hanoi 475


14 Sorting and Searching* (Etext Only) 477


14.1 Selection Sort 478


14.2 Profiling the Selection Sort Algorithm 481


14.3 Analyzing the Performance of the Selection Sort Algorithm 484


ST 1 Oh, Omega, and Theta 486


ST 2 Insertion Sort 487


14.4 Merge Sort 488


14.5 Analyzing the Merge Sort Algorithm 491


ST 3 The Quicksort Algorithm 493


14.6 Searching 495


Linear Search 495


Binary Search 497


14.7 PROBLEM SOLVING Estimating the Running Time of an Algorithm 500


Linear Time 500


Quadratic Time 501


The Triangle Pattern 502


Logarithmic Time 503


14.8 Sorting and Searching in the Java Library 504


Sorting 504


Binary Search 505


Comparing Objects 505


ST 4 The Comparator Interface 506


ST 5 Comparators with Lambda Expressions 507


WE 1 Enhancing the Insertion Sort Algorithm 507


15 The Java Collections Framework* (Etext Only) 511


15.1 An Overview of the Collections Framework 512


15.2 Linked Lists 514


The Structure of Linked Lists 515


The LinkedList Class of the Java Collections Framework 516


List Iterators 516


15.3 Sets 520


Choosing a Set Implementation 520


Working with Sets 522


15.4 Maps 525


ST 1 Updating Map Entries 527


HT 1 Choosing a Collection 527


WE 1 Word Frequency 528


ST 2 Hash Functions 529


15.5 Stacks, Queues, and Priority Queues 531


Stacks 531


Queues 532


Priority Queues 533


15.6 Stack and Queue Applications 534


Balancing Parentheses 534


Evaluating Reverse Polish Expressions 535                                                 


Evaluating Algebraic Expressions 537


Backtracking 540


ST 3 Reverse Polish Notation 542


WE 2 Simulating a Queue of Waiting Customers 543


Appendix A The Basic Latin and Latin-1 Subsets of Unicode A-1


Appendix B JAVA Operator Summary A-5


Appendix C JAVA Reserved Word Summary A-7


Appendix D The JAVA Library A-9


Appendix E JAVA Language Coding Guidelines A-29


Appendix F Tool Summary (Etext Only)


Appendix G Number Systems (Etext Only)


Appendix H UML Summary (Etext Only)


Appendix I JAVA Syntax Summary (Etext Only)


Appendix J HTML Summary (Etext Only)


Glossary G-1


Index I-1


Credits C-1


Quick Reference C-3