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2010-06-01T06:36:20Z

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в 18:01, 31 мая 2010

2010-05-31T18:01:44Z

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== Composition with public objects ==



<source lang="java">

// : c06:Car.java
// Composition with public objects.
// From "Thinking in Java, 3rd ed." (c) Bruce Eckel 2002
// www.BruceEckel.ru. See copyright notice in CopyRight.txt.
class Engine {
public void start() {
}
public void rev() {
}
public void stop() {
}
}
class Wheel {
public void inflate(int psi) {
}
}
class Window {
public void rollup() {
}
public void rolldown() {
}
}
class Door {
public Window window = new Window();
public void open() {
}
public void close() {
}
}
public class Car {
public Engine engine = new Engine();
public Wheel[] wheel = new Wheel[4];
public Door left = new Door(), right = new Door(); // 2-door
public Car() {
for (int i = 0; i < 4; i++)
wheel[i] = new Wheel();
}
public static void main(String[] args) {
Car car = new Car();
car.left.window.rollup();
car.wheel[0].inflate(72);
}
} ///:~

</source>



== Create a Singleton Object ==



<source lang="java">

class MySingleton {
// the static singleton object
private static MySingleton theObject;
private MySingleton() {
}
public static MySingleton createMySingleton() {
if (theObject == null)
theObject = new MySingleton();
return theObject;
}
}
public class Main {
public static void main(String[] args) {
MySingleton ms1 = MySingleton.createMySingleton();
MySingleton ms2 = MySingleton.createMySingleton();
System.out.println(ms1 == ms2);
}
}

</source>



== The protected keyword ==



<source lang="java">

// : c06:Orc.java
// The protected keyword.
// From "Thinking in Java, 3rd ed." (c) Bruce Eckel 2002
// www.BruceEckel.ru. See copyright notice in CopyRight.txt.

class Villain {
private String name;
protected void set(String nm) {
name = nm;
}
public Villain(String name) {
this.name = name;
}
public String toString() {
return "I"m a Villain and my name is " + name;
}
}
public class Orc extends Villain {
private int orcNumber;
public Orc(String name, int orcNumber) {
super(name);
this.orcNumber = orcNumber;
}
public void change(String name, int orcNumber) {
set(name); // Available because it"s protected
this.orcNumber = orcNumber;
}
public String toString() {
return "Orc " + orcNumber + ": " + super.toString();
}
public static void main(String[] args) {
Orc orc = new Orc("Limburger", 12);
System.out.println(orc);
orc.change("Bob", 19);
System.out.println(orc);
}
} ///:~

</source>



== Visibility ==



<source lang="java">

/*
* Copyright (c) Ian F. Darwin, http://www.darwinsys.ru/, 1996-2002.
* All rights reserved. Software written by Ian F. Darwin and others.
* $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS""
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* Java, the Duke mascot, and all variants of Sun"s Java "steaming coffee
* cup" logo are trademarks of Sun Microsystems. Sun"s, and James Gosling"s,
* pioneering role in inventing and promulgating (and standardizing) the Java
* language and environment is gratefully acknowledged.
*
* The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
* inventing predecessor languages C and C++ is also gratefully acknowledged.
*/

public class Visibility {
final int i = 42;
void method1() {
// int i = 13; // would conflict with line below
for (int i=0; i<10; i++) // does not corrupt object"s i
// for (int i=0; i<3; i++) // not allowed, use j
System.out.println("i = " + i); // prints 0, 1, ...
System.out.println("i = " + i); // prints 42
}
}

</source>

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Admin: 1 версия

в 18:01, 31 мая 2010