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============================================================================================
Learn More About Java2 Professional Tutrial Vol.2 I-ichirow Suzuki
============================================================================================
Learn More About Java2 Professional Tutrial
Chapter 1 変数とオブジェクト
Chapter 2 お約束とコメント
Chapter 3 メソッドと基本制御
Chapter 4 コンストラクタと初期化
Chapter 5 クラスの再利用
Chapter 6 継承
Chapter 7 ポリモフィズム
Chapter 8 インターフェイスとインナークラス
Chapter 9 コレクション
Chapter10 エラーハンドリング
Chapter11 ファイル入出力
Chapter12 Creating Windows AWT
Chapter13 Creating Windows Swing
Chapter14 Multiple Threads
Chapter15 ネットワーク
Chapter16 アルゴリズムとデータ構造
///////////////////////////////////////////////////////////////////////////////////////////
//// Chapter 5 クラスの再利用
//---------------------------------------------------
//: c05:SprinklerSystem.java
// 宣言時の変数の値
class WaterSource
{
private String s;
WaterSource()
{
System.out.println("WaterSource()");
s = new String("Constructed");
}
public String toString()
{
return s;
}
}
public class SprinklerSystem
{
private String valve1, valve2, valve3, valve4;
// WaterSource source = new WaterSource() ;
WaterSource source;
int i;
float f;
void print()
{
System.out.println("valve1 = " + valve1);
System.out.println("valve2 = " + valve2);
System.out.println("valve3 = " + valve3);
System.out.println("valve4 = " + valve4);
System.out.println("i = " + i);
System.out.println("f = " + f);
System.out.println("source = " + source);
}
public static void main(String[] args)
{
SprinklerSystem x = new SprinklerSystem();
x.print();
}
}
/**
* valve1 = null
* valve2 = null
* valve3 = null
* valve4 = null
* i = 0
* f = 0.0
* source = null
*/
//---------------------------------------------------
//: c05:Bath.java
// コンストラクタの必要性と toString()の意味
class Soap
{
private String s;
Soap()
{
System.out.println("Soap()");
s = new String("Constructed");
}
public String toString()
{
return s;
}
}
public class Bath
{
private String s1 = new String("Happy") ;// Initializing at point of definition:
private String s2 = "Happy" ;
private String s3 ;
private String s4 ;
Soap castille;
int i;
float toy;
public Bath()
{
System.out.println("Inside Bath()");
s3 = new String("Joy");
i = 47;
toy = 3.14f;
castille = new Soap();
}
void print()
{
// Delayed initialization:
if(s4 == null)
{
s4 = new String("Joy");
}
System.out.println("s1 = " + s1);
System.out.println("s2 = " + s2);
System.out.println("s3 = " + s3);
System.out.println("s4 = " + s4);
System.out.println("i = " + i);
System.out.println("toy = " + toy);
System.out.println("castille = " + castille);
}
public static void main(String[] args)
{
Bath b = new Bath();
b.print();
}
}
/**
* Inside Bath()
* Soap()
* s1 = Happy
* s2 = Happy
* s3 = Joy
* s4 = Joy
* i = 47
* toy = 3.14
* castille = Constructed
*/
///////////////////////////////////////////////////////////////////////////////////////////
//// Chapter 6 継承
//: c06:Detergent.java 継承
class Cleanser
{
private String s = new String("Cleanser");
public void append(String a)
{
s += a;
}
public void dilute()
{
append(" dilute()");
}
public void apply()
{
append(" apply()");
}
public void scrub()
{
append(" scrub()");
}
public void print()
{
System.out.println(s);
}
public static void main(String[] args)
{
Cleanser x = new Cleanser();
x.dilute();
x.apply();
x.scrub();
x.print();
}
}
public class Detergent extends Cleanser
{
// Change a method:
public void scrub()
{
append(" Detergent.scrub()");
super.scrub(); // Call base-class version
}
// Add methods to the interface:
public void foam()
{
append(" foam()");
}
// Test the new class:
public static void main(String[] args)
{
Detergent x = new Detergent();
x.dilute();
x.apply();
x.scrub();
x.foam();
x.print();
System.out.println("Testing base class:");
Cleanser.main(args);
}
}
/**
* Cleanser dilute() apply() Detergent.scrub()
* Testing base class:
* Cleanser dilute() apply() scrub()
*/
//---------------------------------------------------
//: c06:Cartoon.java 継承クラスの実行順序
// 継承先から実行される事に注意
class Art
{
public Art()
{
System.out.println("Art constructor");
}
}
class Drawing extends Art
{
public Drawing()
{
System.out.println("Drawing constructor");
}
}
public class Cartoon extends Drawing
{
public Cartoon()
{
System.out.println("Cartoon constructor");
}
public static void main(String[] args)
{
Cartoon x = new Cartoon();
}
}
/**
* Art constructor
* Drawing constructor
* Cartoon constructor
*/
//---------------------------------------------------
//: c06:Chess.java 継承の場合のスーパークラスへの値渡し
class Game
{
public Game(int i)
{
System.out.println("Game constructor i = " + i);
}
}
class BoardGame extends Game
{
public BoardGame(int i)
{
super(i);
System.out.println("BoardGame constructor i = " + i);
}
}
public class Chess extends BoardGame
{
public Chess()
{
super(11);
System.out.println("Chess constructor i = " + i);
}
public static void main(String[] args)
{
Chess x = new Chess();
}
}
/**
* Game constructor i = 11
* BoardGame constructor i = 11
* Chess constructor
*/
//---------------------------------------------------
//: c06:Hide.java スーパークラスコンストラクタのオーバーロード
class Homer
{
char doh(char c)
{
System.out.println("doh(char)");
return 'd';
}
float doh(float f)
{
System.out.println("doh(float)");
return 1.0f;
}
}
class Milhouse {}
class Bart extends Homer
{
void doh(Milhouse m) {}
}
class Hide
{
public static void main(String[] args)
{
Bart b = new Bart();
b.doh(1); // doh(float) used
b.doh('x');
b.doh(1.0f);
b.doh(new Milhouse());
}
}
/**
* doh(float)
* doh(char)
* doh(float)
*/
//---------------------------------------------------
//: c06:Wind.java クラスオブジェクトを渡す
class Instrument
{
public void play()
{
System.out.println("play....") ;
}
static void tune(Instrument i)
{
i.play();
}
}
class Wind extends Instrument
{
public static void main(String[] args)
{
Wind flute = new Wind();
Instrument.tune(flute); // Upcasting
}
}
//---------------------------------------------------
//: c06:BlankFinal.java final 修飾子
class Poppet { }
class BlankFinal
{
final int i = 0; // Initialized final
final int j; // Blank final
final Poppet p; // Blank final reference
// Blank finals MUST be initialized in the constructor:
BlankFinal()
{
// i = 1 ; // Error!
j = 1; // Initialize blank final
p = new Poppet();
}
public static void main(String[] args)
{
BlankFinal bf = new BlankFinal();
}
}
//---------------------------------------------------
//: c06:Jurassic.java finalクラスはextendsできない
class SmallBrain {}
final class Dinosaur
{
int i = 7;
int j = 1;
SmallBrain x = new SmallBrain();
void f() {}
}
public class Jurassic
{
public static void main(String[] args)
{
Dinosaur n = new Dinosaur();
n.f();
n.i = 40;
n.j++;
}
}
//---------------------------------------------------
//: c06:Beetle.java スーパークラスを含む場合の実行プロセス分析
class Insect
{
int i = 9;
int j;
static int x1 = prt("static Insect.x1 initialized");
public Insect()
{
prt("i = " + i + ", j = " + j);
j = 39;
}
static int prt(String s)
{
System.out.println(s);
return 47;
}
}
public class Beetle extends Insect
{
int k = prt("Beetle.k initialized");
static int x2 = prt("static Beetle.x2 initialized");
public Beetle() //ここを実行する前にsuperクラスのコンストラクタを実行
{
prt("k = " + k);
prt("j = " + j);
}
public static void main(String[] args)
{
prt("Beetle constructor");
Beetle b = new Beetle();
}
}
/**
* static Insect.x1 initialized
* static Beetle.x2 initialized
* Beetle constructor
* i = 9, j = 0
* Beetle.k initialized
* k = 47
* j = 39
*/
///////////////////////////////////////////////////////////////////////////////////////////
//// Chapter 7: ポリモフィズム
//------------------------------------------------
//: c07:music:Music.java
class Note
{
private int value;
private Note(int val)
{
value = val;
}
public int getValue()
{
return value ;
}
public static final Note MIDDLE_C = new Note(0) ;
public static final Note C_SHARP = new Note(1) ;
public static final Note B_FLAT = new Note(2);
}
class Instrument
{
public void play(Note n)
{
System.out.println("Instrument.play()");
}
}
class Wind extends Instrument
{
// Redefine interface method:
public void play(Note n)
{
System.out.println("Wind.play() : " + n.getValue());
}
}
public class Music
{
public static void tune(Instrument i)
{
// ...
i.play(Note.MIDDLE_C);
}
public static void main(String[] args)
{
Wind flute = new Wind();
tune(flute); // Upcasting
}
}
/**
* Wind.play() : 0
*/
//------------------------------------------------
//: c07:Shapes.java ポリモフィズムとは
class Shape
{
void draw()
{
System.out.println("Shape.draw()");
}
void erase()
{
System.out.println("Shape.draw()");
}
}
class Circle extends Shape
{
void draw()
{
System.out.println("Circle.draw()");
}
void erase()
{
System.out.println("Circle.erase()");
}
}
class Square extends Shape
{
void draw()
{
System.out.println("Square.draw()");
}
void erase()
{
System.out.println("Square.erase()");
}
}
class Triangle extends Shape
{
void draw()
{
System.out.println("Triangle.draw()");
}
void erase()
{
System.out.println("Triangle.erase()");
}
}
public class Shapes
{
public static Shape randShape()
{
switch((int)(Math.random() * 3))
{
default:
case 0: return new Circle();
case 1: return new Square();
case 2: return new Triangle();
}
}
public static void main(String[] args)
{
Shape[] s = new Shape[9];
for(int i = 0; i < s.length; i++)// Fill up the array with shapes:
{
s[i] = randShape();
}
for(int i = 0; i < s.length; i++)// Make polymorphic method calls:
{
s[i].draw();
}
}
}
/**
* Circle.draw()
* Triangle.draw()
* Circle.draw()
* Circle.draw()
* Circle.draw()
* Square.draw()
* Triangle.draw()
* Square.draw()
* Square.draw()
*/
//------------------------------------------------
//: c07:WindError.java
// 引っかかるな ポリモフィズム２
class NoteX
{
public static final int
MIDDLE_C = 0 ;
C_SHARP = 1 ;
C_FLAT = 2;
}
class InstrumentX
{
public void play(int NoteX) // This one
{
System.out.println("InstrumentX.play()");
}
}
class WindX extends InstrumentX
{
// OOPS! Changes the method interface:
public void play(NoteX n)
{
System.out.println("WindX.play(NoteX n)");
}
}
public class WindError
{
public static void tune(InstrumentX i)
{
i.play(NoteX.MIDDLE_C);//MIDDLE_C = 0 ;
}
public static void main(String[] args)
{
WindX flute = new WindX();
tune(flute); // Not the desired behavior!
}
}
/**
* InstrumentX.play()
*/
//------------------------------------------------
//: c07:Sandwich.java コンストラクタからの呼び出し
class Bread
{
Bread() { System.out.println("Bread()"); }
}
class Cheese
{
Cheese() { System.out.println("Cheese()"); }
}
class Lettuce
{
Lettuce() { System.out.println("Lettuce()"); }
}
class Meal
{
Meal() { System.out.println("Meal()"); }
}
class Lunch extends Meal
{
Lunch() { System.out.println("Lunch()");}
}
class PortableLunch extends Lunch
{
PortableLunch() {System.out.println("PortableLunch()"); }
}
class Sandwich extends PortableLunch
{
Bread b = new Bread();
Cheese c = new Cheese();
Lettuce l = new Lettuce();
Sandwich()
{
System.out.println("Sandwich()");
}
public static void main(String[] args)
{
new Sandwich();
}
}
/**
* Meal()
* Lunch()
* PortableLunch()
* Bread()
* Cheese()
* Lettuce()
* Sandwich()
*/
//------------------------------------------------
//: c07:PolyConstructors.java
// extendsを考える
abstract class Glyph
{
abstract void draw();
Glyph()
{
System.out.println("Glyph() before draw()");
draw();
System.out.println("Glyph() after draw()");
}
}
class RoundGlyph extends Glyph
{
int radius = 1;
RoundGlyph(int r)
{
radius = r;
System.out.println("RoundGlyph.RoundGlyph(), radius = " + radius);
}
void draw()
{
System.out.println("RoundGlyph.draw(), radius = " + radius);
}
}
public class PolyConstructors
{
public static void main(String[] args)
{
new RoundGlyph(5);
}
}
/**
* Glyph() before draw()
* RoundGlyph.draw(), radius = 0
* Glyph() after draw()
* RoundGlyph.RoundGlyph(), radius = 5
*/
//------------------------------------------------
//: c07:Transmogrify.java new で自在に操る
abstract class Actor
{
abstract void act();
}
class HappyActor extends Actor
{
public void act()
{
System.out.println("HappyActor");
}
}
class SadActor extends Actor
{
public void act()
{
System.out.println("SadActor");
}
}
class Stage
{
Actor a = new HappyActor();// This one
void go()
{
a.act();
}
void change()
{
a = new SadActor(); // and this one!
}
}
public class Transmogrify
{
public static void main(String[] args)
{
Stage s = new Stage();
s.go(); // Prints "HappyActor"
s.change();
s.go(); // Prints "SadActor"
}
}
/**
* HappyActor
* SadActor
*/
]]>インターネットスタートページ 鈴木維一郎 石橋三重子
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