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============================================================================================
Learn More About Java2 Professional Tutrial Vol.3
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 8: インターフェイスとインナークラス
//: c08:Adventure.java
// インターフェイスのimplements
import java.util.*;
interface CanFight
{
void fight();
}
interface CanSwim
{
void swim();
}
interface CanFly
{
void fly();
}
class ActionCharacter
{
public void fight() {}
}
class Hero extends ActionCharacter implements CanFight, CanSwim, CanFly
{
public void swim() {}
public void fly() {}
}
public class Adventure
{
static void t(CanFight x)
{
x.fight();
}
static void u(CanSwim x)
{
x.swim();
}
static void v(CanFly x)
{
x.fly();
}
static void w(ActionCharacter x)
{
x.fight();
}
public static void main(String[] args)
{
Hero h = new Hero();
t(h); // Treat it as a CanFight
u(h); // Treat it as a CanSwim
v(h); // Treat it as a CanFly
w(h); // Treat it as an ActionCharacter
}
}
//------------------------------------------------
//: c08:HorrorShow.java
// インターフェイスの継承とimplements
interface Monster
{
void menace();
}
interface DangerousMonster extends Monster
{
void destroy();
}
class DragonZilla implements DangerousMonster
{
public void menace() {}
public void destroy() {}
}
interface Lethal
{
void kill();
}
interface Vampire extends DangerousMonster, Lethal
{
void drinkBlood();
}
class HorrorShow
{
static void u(Monster b)
{
b.menace();
}
static void v(DangerousMonster d)
{
d.menace();
d.destroy();
}
public static void main(String[] args)
{
DragonZilla if2 = new DragonZilla();
u(if2);
v(if2);
}
}
//------------------------------------------------
//: c08:RandVals.java インターフェイスの使い方
import java.util.*;
interface RandVals
{
int rint = (int)(Math.random() * 10);
long rlong = (long)(Math.random() * 10);
float rfloat = (float)(Math.random() * 10);
double rdouble = Math.random() * 10;
}
//: c08:TestRandVals.java
public class TestRandVals
{
public static void main(String[] args)
{
System.out.println(RandVals.rint);
System.out.println(RandVals.rlong);
System.out.println(RandVals.rfloat);
System.out.println(RandVals.rdouble);
}
}
/**
* 8
* 7
* 6.237678
* 1.3951962033539977
*/
//------------------------------------------------
//: c08:Parcel1.java インナークラス
public class Parcel1
{
class Destination
{
private String label;
Destination(String whereTo)
{
label = whereTo;
}
String readLabel()
{
return label;
}
}
public void ship(String dest)
{
Destination d = new Destination(dest);
System.out.println(d.readLabel());
}
public static void main(String[] args)
{
Parcel1 p = new Parcel1();
p.ship("Tanzania");
}
}
/**
* Tanzania
*/
//------------------------------------------------
//: c08:Parcel2.java return new
public class Parcel2
{
public Destination to(String s)
{
return new Destination(s);
}
class Destination
{
private String label;
Destination(String whereTo)
{
label = whereTo;
}
String readLabel() { return label; }
}
public void ship(String dest)
{
Contents c = cont();
Destination d = to(dest);
System.out.println(d.readLabel());
}
public static void main(String[] args)
{
Parcel2 p = new Parcel2();
p.ship("Tanzania");
}
}
/**
* Tanzania
*/
//------------------------------------------------
//: c08:Parcel5.java
// Nesting a class within a scope.
public class Parcel5 {
private void internalTracking(boolean b)
{
if(b)
{
TrackingSlip ts = new TrackingSlip("slip");
String s = ts.getSlip(); // slip
class TrackingSlip
{
private String id;
TrackingSlip(String s)
{
id = s;
}
String getSlip()
{
return id;
}
}
}
}
public void track()
{
internalTracking(true);
}
public static void main(String[] args)
{
Parcel5 p = new Parcel5();
p.track();
}
}
//------------------------------------------------
//: c08:MultiNestingAccess.java ネスト
class MNA
{
private void f() {}
class A
{
private void g() {}
public class B
{
void h()
{
g();
f();
}
}
}
}
public class MultiNestingAccess
{
public static void main(String[] args)
{
MNA mna = new MNA();
MNA.A mnaa = mna.new A();
MNA.A.B mnaab = mnaa.new B();
mnaab.h();
}
}
//------------------------------------------------
//: c08:InheritInner.java インナークラスの継承
class WithInner
{
class Inner {}
}
public class InheritInner extends WithInner.Inner
{
//! InheritInner() {} // Won't compile
InheritInner(WithInner wi)
{
wi.super();
}
public static void main(String[] args)
{
WithInner wi = new WithInner();
InheritInner ii = new InheritInner(wi);
}
}
//------------------------------------------------
//: c08:BigEgg.java インナークラス実行順序
class Egg
{
private Yolk y;
public Egg()
{
System.out.println("New Egg()");
y = new Yolk();
}
protected class Yolk
{
public Yolk()
{
System.out.println("Egg.Yolk()");
}
}
}
public class BigEgg extends Egg
{
public class Yolk
{
public Yolk()
{
System.out.println("BigEgg.Yolk()");
}
}
public static void main(String[] args)
{
new BigEgg();
}
}
/**
* New Egg()
* Egg.Yolk()
*/
///////////////////////////////////////////////////////////////////////////////////////////
//// Chapter 9: コレクション
//------------------------------------------------
//: c09:PrintingContainers.java fill() ;
import java.util.*;
public class PrintingContainers
{
static Collection fill(Collection c)
{
c.add("dog");
c.add("dog");
c.add("cat");
return c;
}
static Map fill(Map m)
{
m.put("dog", "Bosco");
m.put("dog", "Spot");
m.put("cat", "Rags");
return m;
}
public static void main(String[] args)
{
System.out.println(fill(new ArrayList()));
System.out.println(fill(new HashSet()));
System.out.println(fill(new HashMap()));
}
}
/**
* [dog, dog, cat]
* [cat, dog]
* {cat=Rags, dog=Spot}
*/
//------------------------------------------------
//: c09:FillingLists.java fill() ;
import java.util.*;
public class FillingLists
{
public static void main(String[] args)
{
List list = new ArrayList();
for(int i = 0; i < 10; i++)
{
list.add("");
}
Collections.fill(list, "Hello");
System.out.println(list);
}
}
/**
* [Hello, Hello, Hello, Hello, Hello, Hello, Hello, Hello, Hello, Hello]
*/
//------------------------------------------------
//: c09:CatsAndDogs.java コンテナ
import java.util.*;
class Cat
{
private int catNumber;
Cat(int i)
{
catNumber = i;
}
void print()
{
System.out.println("Cat #" + catNumber);
}
}
class Dog
{
private int dogNumber;
Dog(int i)
{
dogNumber = i;
}
void print()
{
System.out.println("Dog #" + dogNumber);
}
}
public class CatsAndDogs
{
public static void main(String[] args)
{
ArrayList cats = new ArrayList();
for(int i = 0; i < 7; i++)
{
cats.add(new Cat(i));
}
// Not a problem to add a dog to cats:
cats.add(new Dog(7));
for(int i = 0; i < cats.size(); i++)
{
((Cat)cats.get(i)).print();
}
// Dog is detected only at run-time
}
}
/**
* Cat #0
* Cat #1
* Cat #2
* Cat #3
* Cat #4
* Cat #5
* Cat #6
*/
//------------------------------------------------
//: c09:WorksAnyway.java toString()の使い方
import java.util.*;
class Mouse
{
private int mouseNumber;
Mouse(int i)
{
mouseNumber = i;
}
// Override Object.toString():
public String toString()
{
return "This is Mouse #" + mouseNumber;
}
public int getNumber()
{
return mouseNumber;
}
}
class MouseTrap
{
static void caughtYa(Object m)
{
Mouse mouse = (Mouse)m; // Cast from Object
System.out.println("Mouse: " + mouse.getNumber());
}
}
public class WorksAnyway
{
public static void main(String[] args)
{
ArrayList mice = new ArrayList();
for(int i = 0; i < 3; i++)
{
mice.add(new Mouse(i));
}
for(int i = 0; i < mice.size(); i++)
{
// No cast necessary, automatic
// call to Object.toString():
System.out.println("Free mouse: " + mice.get(i));
MouseTrap.caughtYa(mice.get(i));
}
}
}
/**
* Free mouse: This is Mouse #0
* Mouse: 0
* Free mouse: This is Mouse #1
* Mouse: 1
* Free mouse: This is Mouse #2
* Mouse: 2
*/
//------------------------------------------------
//: c09:HamsterMaze.java イテレータの使い方
import java.util.*;
class Hamster
{
private int hamsterNumber;
Hamster(int i)
{
hamsterNumber = i;
}
public String toString()
{
return "This is Hamster #" + hamsterNumber;
}
}
class Printer
{
static void printAll(Iterator e)
{
while(e.hasNext())
{
System.out.println(e.next());
}
}
}
public class HamsterMaze
{
public static void main(String[] args)
{
ArrayList v = new ArrayList();
for(int i = 0; i < 3; i++)
{
v.add(new Hamster(i));
}
Printer.printAll(v.iterator());
}
}
/**
* This is Hamster #0
* This is Hamster #1
* This is Hamster #2
*/
//------------------------------------------------
//: c09:Queue.java キュー
import java.util.*;
public class Queue
{
private LinkedList list = new LinkedList();
public void put(Object v)
{
list.addFirst(v);
}
public Object get()
{
return list.removeLast();
}
public boolean isEmpty()
{
return list.isEmpty();
}
public static void main(String[] args)
{
Queue queue = new Queue();
for(int i = 0; i < 10; i++)
{
queue.put(Integer.toString(i));
}
while(!queue.isEmpty())
{
System.out.println(queue.get());
}
}
}
/**
* 0
* 1
* 2
* 3
* 4
* 5
* 6
* 7
* 8
* 9
*/
//------------------------------------------------
//: c09:Stacks.java スタック
import java.util.*;
public class Stacks
{
static String[] months = {
"January", "February", "March", "April",
"May", "June", "July", "August", "September",
"October", "November", "December" };
public static void main(String[] args)
{
Stack stk = new Stack();
for(int i = 0; i < months.length; i++)
{
stk.push(months[i] + " ");
}
System.out.println("stk = " + stk);
// Treating a stack as a Vector:
stk.addElement("The last line");
System.out.println( "element 5 = " + stk.elementAt(5));
System.out.println("popping elements:");
while(!stk.empty())
{
System.out.println(stk.pop());
}
}
}
/* stk = [January , February , March , April , May , June , July , August , September ,
October , November , December ]
* element 5 = June
* popping elements:
* The last line
* December
* November
* October
* September
* August
* July
* June
* May
* April
* March
* February
* January
*/
///////////////////////////////////////////////////////////////////////////////////////////
//// Chapter 10: エラーハンドリング
//: c10:SimpleExceptionDemo.java
// throws
class SimpleException extends Exception {}
public class SimpleExceptionDemo
{
public void f() throws SimpleException
{
System.out.println( "Throwing SimpleException from f()");
throw new SimpleException ();
}
public static void main(String[] args)
{
SimpleExceptionDemo sed = new SimpleExceptionDemo();
try
{
sed.f();
}
catch(SimpleException e)
{
System.err.println("Caught it!");
}
}
}
/* Throwing SimpleException from f()
* Caught it!
*/
//------------------------------------------------
//: c10:FullConstructors.java
// StackTrace
class MyException extends Exception
{
public MyException() {}
public MyException(String msg)
{
super(msg);
}
}
public class FullConstructors
{
public static void f() throws MyException
{
System.out.println("Throwing MyException from f()");
throw new MyException();
}
public static void g() throws MyException
{
System.out.println("Throwing MyException from g()");
throw new MyException("Originated in g()");
}
public static void main(String[] args)
{
try
{
f();
}
catch(MyException e)
{
e.printStackTrace(System.err);
}
try
{
g();
}
catch(MyException e)
{
e.printStackTrace(System.err);
}
}
}
/*
* Throwing MyException from f()
* MyException
* at hoe.f(hoe.java:14)
* at hoe.main(hoe.java:25)
* Throwing MyException from g()
* MyException: Originated in g()
* at hoe.g(hoe.java:19)
* at hoe.main(hoe.java:33)
*/
//------------------------------------------------
//: c10:ExceptionMethods.java
public class ExceptionMethods
{
public static void main(String[] args)
{
try
{
throw new Exception("Here's my Exception");
}
catch(Exception e)
{
System.err.println("Caught Exception");
System.err.println("e.getMessage(): " + e.getMessage());
System.err.println("e.getLocalizedMessage(): " + e.getLocalizedMessage());
System.err.println("e.toString(): " + e);
System.err.println("e.printStackTrace():");
e.printStackTrace(System.err);
}
}
}
/*
* Caught Exception
* e.getMessage(): Here's my Exception
* e.getLocalizedMessage(): Here's my Exception
* e.toString(): java.lang.Exception: Here's my Exception
* e.printStackTrace():
* java.lang.Exception: Here's my Exception
* at hoe.main(hoe.java:7)
*/
//------------------------------------------------
//: c10:Rethrowing.java
public class Rethrowing
{
public static void f() throws Exception
{
System.out.println("originating the exception in f()");
throw new Exception("thrown from f()");
}
public static void g() throws Throwable
{
try
{
f();
}
catch(Exception e)
{
System.err.println("Inside g(), e.printStackTrace()");
e.printStackTrace(System.err);
throw e;
}
}
public static void main(String[] args) throws Throwable
{
try
{
g();
}
catch(Exception e)
{
System.err.println("Caught in main, e.printStackTrace()");
e.printStackTrace(System.err);
}
}
}
/*
* originating the exception in f()
* Inside g(), e.printStackTrace()
* java.lang.Exception: thrown from f()
* at hoe.f(hoe.java:6)
* at hoe.g(hoe.java:12)
* at hoe.main(hoe.java:26)
* Caught in main, e.printStackTrace()
* java.lang.Exception: thrown from f()
* at hoe.f(hoe.java:6)
* at hoe.g(hoe.java:12)
* at hoe.main(hoe.java:26)
*/
//------------------------------------------------
//: c10:ThrowOut.java
public class ThrowOut
{
public static void main(String[] args) throws Throwable
{
try
{
throw new Throwable();
}
catch(Exception e)
{
System.err.println("Caught in main()");
}
}
}
//------------------------------------------------
//: c10:RethrowNew.java
// Rethrow a different object
// from the one that was caught.
class OneException extends Exception
{
public OneException(String s) { super(s); }
}
class TwoException extends Exception
{
public TwoException(String s) { super(s); }
}
public class RethrowNew
{
public static void f() throws OneException
{
System.out.println("originating the exception in f()");
throw new OneException("thrown from f()");
}
public static void main(String[] args) throws TwoException
{
try
{
f();
}
catch(OneException e)
{
System.err.println("Caught in main, e.printStackTrace()");
e.printStackTrace(System.err);
throw new TwoException("from main()");
}
}
}
/*
* originating the exception in f()
* Caught in main, e.printStackTrace()
* OneException: thrown from f()
* at hoe.f(hoe.java:14)
* at hoe.main(hoe.java:20)
* Exception in thread "main" TwoException: from main()
* at hoe.main(hoe.java:26)
*/
//------------------------------------------------
//: c10:FinallyWorks.java finally
class ThreeException extends Exception {}
public class FinallyWorks
{
static int count = 0;
public static void main(String[] args)
{
while(true)
{
try
{
// Post-increment is zero first time:
if(count++ == 0)
throw new ThreeException();
System.out.println("No exception");
}
catch(ThreeException e)
{
System.err.println("ThreeException");
}
finally
{
System.err.println("In finally clause");
if(count == 2)
break; // out of "while"
}
}
}
}
/**
* ThreeException
* In finally clause
* No exception
* In finally clause
*/
//------------------------------------------------
//: c10:Human.java
class Annoyance extends Exception {}
class Sneeze extends Annoyance {}
public class Human
{
public static void main(String[] args)
{
try
{
throw new Sneeze();
}
catch(Sneeze s)
{
System.err.println("Caught Sneeze");
}
catch(Annoyance a)
{
System.err.println("Caught Annoyance");
}
}
}
/**
* Caught Sneeze
*/
]]>
I-ichirow Suzuki _/_/_/_/_/_/_/_/_/_/_
URL : www.kg-group.com Top Page
Mail : suzuki@kg-group.com
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