, . , new. , Rectangle :
Rectangle rect = new Rectangle(20, 10); |
rect, :
rect.setWidth(20); System.out.println(": "+rect.getWidth()); |
1. , (Circle). , . CircleTest, main(String[] args).
2. , (Human). (Head, Leg, Hand). . Human.
3. , (Book). (, , . .) , . BookTest, main(String[] args).
3
JAVA
:
- , Java.
:
- . . , Person, :
public class Person { private String name; private String surname; public String getName() { return name; } public String getSurname() { return surname; } public Person(String name, String surname){ this.name=name; this.surname=surname; } public void displayInfo(){ System.out.println(": " + name + " : " + surname); } } |
, , , , - Employee. , Person, - , Employee ( ) Person, , , :
classEmployeeextendsPerson{ } |
, - extends, . Employee Person, Employee , Person.
|
|
Employee , . , , - .
, displayInfo() Person Employee:
class Employee extends Person{ private String company; public Employee(String name, String surname, String company) { super(name, surname); this.company=company; } public void displayInfo(){ super.displayInfo(); System.out.println(": " + company); } } |
Employee , . , .
name surname Person private, Employee. . , super, .
super - , private.
Employee displayInfo() . super displayInfo(), , , Employee.
, displayInfo() :
public void displayInfo(){ System.out.println(": " + super.getName() + " : " + super.getSurname() + " : " + company); } |
. , getName() getSurname(). - . :
public static void main(String[] args) { Employee empl = new Employee("Tom", "Simpson", "Oracle"); empl.displayInfo(); String firstName = empl.getName(); System.out.println(firstName); } |
, . final. :
public final class Person { } |
Person , , :
classEmployeeextendsPerson{ } |
. , displayInfo(), :
public class Person { //........................ public final void displayInfo(){ System.out.println(": " + name + " : " + surname); } } |
Employee .
|
|
Java . . , . -. .
abstract:
public abstract class Human{ privateint height; private double weight; publicintgetHeight() { return height; } public double getWeight() { return weight; } } |
. abstract :
public abstractvoiddisplayInfo(); |
, . , , .
? , : Person, , Employee, , Client, . , Employee Client Person, . , , Person . .
public abstract class Person { private String name; private String surname; public String getName() { return name; } public String getSurname() { return surname; } public Person(String name, String surname){ this.name=name; this.surname=surname; } public abstract void displayInfo(); } class Employee extends Person{ private String bank; public Employee(String name, String surname, String company) { super(name, surname); this.bank=company; } public void displayInfo(){ System.out.println(": " + super.getName() + " : " + super.getSurname() + " : " + bank); } } class Client extends Person { private String bank; public Client(String name, String surname, String company) { super(name, surname); this.bank=company; } public void displayInfo(){ System.out.println(": " + super.getName() + " : " + super.getSurname() + " : " + bank); } } |
1. , (Dish). , . .
2. , (Dog). . .
3. , . . FurnitureShop, . .
4
JAVA.
:
- , Java .
:
, . , , , ++, .
|
|
Java . , , , . .
, interface.
:
public interface Printable{ void print(); } |
, , . .
, public, - . .
, public. . ( java) .
, , . .
, public, - . .
, public. . ( java) .
, implements:
class Book implements Printable{ String name; String author; int year; Book(String name, String author, int year){ this.name = name; this.author = author; this.year = year; } public void print() { System.out.printf(" '%s' ( %s) %d \n", name, author, year); } } |
, , , print.
print:
Book b1 = new Book(" ", ". . ", 1863); b1.print(); |
, :
Printable pr = new Printable(); pr.print(); |
, . , Book , Printable:
public class Journal implements Printable { private String name; String getName(){ return name; } Journal(String name){ this.name = name; } public void print() { System.out.printf(" '%s'\n", name); } } |
Book Journal , Printable. Printable :
Printable printable = new Book("", ". . ", 1863); printable.print(); printable = new Journal(""); printable.print(); |
, :
|
|
public static void main(String[] args) { Printable printable = createPrintable("",false); printable.print(); read(new Book(" ", ". ", 1862)); read(new Journal("")); } static void read(Printable p){ p.print(); } static Printable createPrintable(String name, boolean option){ if(option) return new Book(name, "", 2015); else return new Journal(name); |
read() Printable, Book, Journal.
createPrintable() Printable, Book, Journal.
1. Nameable, getName(), , . (, , , : , , . .).
2. Priceable, getPrice(), . , .
5