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в 18:01, 31 мая 2010

2010-05-31T18:01:44Z

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== Demonstration of both constructor and ordinary method overloading ==



<source lang="java">
// : c04:JavaOverloading.java
// Demonstration of both constructor and ordinary method overloading.
// From "Thinking in Java, 3rd ed." (c) Bruce Eckel 2002
// www.BruceEckel.ru. See copyright notice in CopyRight.txt.

class Tree {
int height;
Tree() {
System.out.println("Planting a seedling");
height = 0;
}
Tree(int i) {
System.out.println("Creating new Tree that is " + i + " feet tall");
height = i;
}
void info() {
System.out.println("Tree is " + height + " feet tall");
}
void info(String s) {
System.out.println(s + ": Tree is " + height + " feet tall");
}
}
public class JavaOverloading {
public static void main(String[] args) {
for (int i = 0; i < 5; i++) {
Tree t = new Tree(i);
t.info();
t.info("overloaded method");
}
// Overloaded constructor:
new Tree();
}
} ///:~

</source>



== Demonstration of overriding fields ==



<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.
*/
/** Demonstration of overriding fields. */
public class OverrideField {
public static void main(String[] av) {
System.out.println("OA"s version of getAttr returns: " +
new OA().getAttr());
System.out.println("OB"s version of getAttr returns: " +
new OB().getAttr());
// Declared as OA, instantiated as OB, so gets OB"s version of things.
OA c = new OB();
System.out.println("C"s version of getAttr returns: " +
c.getAttr());
}
}
class OA {
final int attr = 1;
int getAttr() {
System.out.println("In OA.getAttr");
return attr;
}
}
class OB extends OA {
final int attr = 2;
int getAttr() {
System.out.println("In OB.getAttr");
super.getAttr(); // Just to show flow of control
return attr;
}
}

</source>



== Demotion of primitives and overloading ==



<source lang="java">

// : c04:Demotion.java
// Demotion of primitives and overloading.
// From "Thinking in Java, 3rd ed." (c) Bruce Eckel 2002
// www.BruceEckel.ru. See copyright notice in CopyRight.txt.
public class Demotion {
void f1(char x) {
System.out.println("f1(char)");
}
void f1(byte x) {
System.out.println("f1(byte)");
}
void f1(short x) {
System.out.println("f1(short)");
}
void f1(int x) {
System.out.println("f1(int)");
}
void f1(long x) {
System.out.println("f1(long)");
}
void f1(float x) {
System.out.println("f1(float)");
}
void f1(double x) {
System.out.println("f1(double)");
}
void f2(char x) {
System.out.println("f2(char)");
}
void f2(byte x) {
System.out.println("f2(byte)");
}
void f2(short x) {
System.out.println("f2(short)");
}
void f2(int x) {
System.out.println("f2(int)");
}
void f2(long x) {
System.out.println("f2(long)");
}
void f2(float x) {
System.out.println("f2(float)");
}
void f3(char x) {
System.out.println("f3(char)");
}
void f3(byte x) {
System.out.println("f3(byte)");
}
void f3(short x) {
System.out.println("f3(short)");
}
void f3(int x) {
System.out.println("f3(int)");
}
void f3(long x) {
System.out.println("f3(long)");
}
void f4(char x) {
System.out.println("f4(char)");
}
void f4(byte x) {
System.out.println("f4(byte)");
}
void f4(short x) {
System.out.println("f4(short)");
}
void f4(int x) {
System.out.println("f4(int)");
}
void f5(char x) {
System.out.println("f5(char)");
}
void f5(byte x) {
System.out.println("f5(byte)");
}
void f5(short x) {
System.out.println("f5(short)");
}
void f6(char x) {
System.out.println("f6(char)");
}
void f6(byte x) {
System.out.println("f6(byte)");
}
void f7(char x) {
System.out.println("f7(char)");
}
void testDouble() {
double x = 0;
System.out.println("double argument:");
f1(x);
f2((float) x);
f3((long) x);
f4((int) x);
f5((short) x);
f6((byte) x);
f7((char) x);
}
public static void main(String[] args) {
Demotion p = new Demotion();
p.testDouble();
}
} ///:~

</source>



== Overloaded constructor ==



<source lang="java">

public class Point {
int x, y;
Point(int x, int y) // Overloaded constructor
{
this.x = x;
this.y = y;
}
Point(Point p) // Overloaded constructor
{
this(p.x, p.y);
} // Calls the first constructor
void move(int dx, int dy) {
x += dx;
y += dy;
}
public String toString() {
return "(" + x + ", " + y + ")";
}
}

</source>



== Overloaded method ==



<source lang="java">
public class Overloading {
double method(int i) {
return i;
}
boolean method(boolean b) {
return !b;
}
static double method(int x, double y) {
return x + y + 1;
}
static double method(double x, double y) {
return x + y + 3;
}
public static void main(String[] args) {
System.out.println(method(10, 20));
System.out.println(method(10, 20.0));
System.out.println(method(10.0, 20));
System.out.println(method(10.0, 20.0));
}
}

</source>



== Overloading a base-class method name in a derived class does not hide the base-class versions ==



<source lang="java">
// : c06:Hide.java
// Overloading a base-class method name in a derived class does not hide the base-class versions.
// From "Thinking in Java, 3rd ed." (c) Bruce Eckel 2002
// www.BruceEckel.ru. See copyright notice in CopyRight.txt.
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) {
System.out.println("doh(Milhouse)");
}
}
public class Hide {
public static void main(String[] args) {
Bart b = new Bart();
b.doh(1);
b.doh("x");
b.doh(1.0f);
b.doh(new Milhouse());
}
} ///:~

</source>



== Overloading based on the order of the arguments ==



<source lang="java">
// : c04:OverloadingOrder.java
// Overloading based on the order of the arguments.
// From "Thinking in Java, 3rd ed." (c) Bruce Eckel 2002
// www.BruceEckel.ru. See copyright notice in CopyRight.txt.
public class OverloadingOrder {
static void print(String s, int i) {
System.out.println("String: " + s + ", int: " + i);
}
static void print(int i, String s) {
System.out.println("int: " + i + ", String: " + s);
}
public static void main(String[] args) {
print("String first", 11);
print(99, "Int first");
}
} ///:~

</source>



== Promotion of primitives and overloading ==



<source lang="java">

// : c04:PrimitiveOverloading.java
// Promotion of primitives and overloading.
// From "Thinking in Java, 3rd ed." (c) Bruce Eckel 2002
// www.BruceEckel.ru. See copyright notice in CopyRight.txt.
public class PrimitiveOverloading {
void f1(char x) {
System.out.println("f1(char)");
}
void f1(byte x) {
System.out.println("f1(byte)");
}
void f1(short x) {
System.out.println("f1(short)");
}
void f1(int x) {
System.out.println("f1(int)");
}
void f1(long x) {
System.out.println("f1(long)");
}
void f1(float x) {
System.out.println("f1(float)");
}
void f1(double x) {
System.out.println("f1(double)");
}
void f2(byte x) {
System.out.println("f2(byte)");
}
void f2(short x) {
System.out.println("f2(short)");
}
void f2(int x) {
System.out.println("f2(int)");
}
void f2(long x) {
System.out.println("f2(long)");
}
void f2(float x) {
System.out.println("f2(float)");
}
void f2(double x) {
System.out.println("f2(double)");
}
void f3(short x) {
System.out.println("f3(short)");
}
void f3(int x) {
System.out.println("f3(int)");
}
void f3(long x) {
System.out.println("f3(long)");
}
void f3(float x) {
System.out.println("f3(float)");
}
void f3(double x) {
System.out.println("f3(double)");
}
void f4(int x) {
System.out.println("f4(int)");
}
void f4(long x) {
System.out.println("f4(long)");
}
void f4(float x) {
System.out.println("f4(float)");
}
void f4(double x) {
System.out.println("f4(double)");
}
void f5(long x) {
System.out.println("f5(long)");
}
void f5(float x) {
System.out.println("f5(float)");
}
void f5(double x) {
System.out.println("f5(double)");
}
void f6(float x) {
System.out.println("f6(float)");
}
void f6(double x) {
System.out.println("f6(double)");
}
void f7(double x) {
System.out.println("f7(double)");
}
void testConstVal() {
System.out.println("Testing with 5");
f1(5);
f2(5);
f3(5);
f4(5);
f5(5);
f6(5);
f7(5);
}
void testChar() {
char x = "x";
System.out.println("char argument:");
f1(x);
f2(x);
f3(x);
f4(x);
f5(x);
f6(x);
f7(x);
}
void testByte() {
byte x = 0;
System.out.println("byte argument:");
f1(x);
f2(x);
f3(x);
f4(x);
f5(x);
f6(x);
f7(x);
}
void testShort() {
short x = 0;
System.out.println("short argument:");
f1(x);
f2(x);
f3(x);
f4(x);
f5(x);
f6(x);
f7(x);
}
void testInt() {
int x = 0;
System.out.println("int argument:");
f1(x);
f2(x);
f3(x);
f4(x);
f5(x);
f6(x);
f7(x);
}
void testLong() {
long x = 0;
System.out.println("long argument:");
f1(x);
f2(x);
f3(x);
f4(x);
f5(x);
f6(x);
f7(x);
}
void testFloat() {
float x = 0;
System.out.println("float argument:");
f1(x);
f2(x);
f3(x);
f4(x);
f5(x);
f6(x);
f7(x);
}
void testDouble() {
double x = 0;
System.out.println("double argument:");
f1(x);
f2(x);
f3(x);
f4(x);
f5(x);
f6(x);
f7(x);
}
public static void main(String[] args) {
PrimitiveOverloading p = new PrimitiveOverloading();
p.testConstVal();
p.testChar();
p.testByte();
p.testShort();
p.testInt();
p.testLong();
p.testFloat();
p.testDouble();
}
} ///:~

</source>

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Admin: 1 версия

в 18:01, 31 мая 2010