contone operator

"Halo, Amigo! Sampeyan wis ketemu operator instanceof . Dina iki aku arep ngomong carane lan ngendi iku bisa digunakake. instanceof iku operator banget prasaja lan efisien."

"Iki kaya iklan!"

"Pancen prasaja banget. Iki digunakake kaya iki: «obyek» instanceof «kelas» ."

Priksa manawa obyek minangka conto saka kelas tartamtu. Iku luwih gampang tinimbang nerangake. Deleng conto iki:

Object o = new Integer(3);
boolean isInt = o instanceof Integer;

Object o = "Mama";
boolean isInt = o instanceof Integer;

InputStream is = new FileInputStream("");
boolean isFIS = is instanceof FileInputStream;

"Ya, iku prasaja banget."

"Operator iki uga nyathet warisan. Priksa."

class Animal
{
}
class Cat extends Animal
{
}
class Tiger extends Cat
{
}

Object o = new Tiger();
boolean isCat = o instanceof Cat;
boolean isTiger = o instanceof Tiger;
boolean isAnimal = o instanceof Animal;

Object o = new Animal();
boolean isCat = o instanceof Cat;
boolean isTiger = o instanceof Tiger;
boolean isAnimal = o instanceof Animal;

Lan malah antarmuka:

interface Moveable
{
}
class Cat
{
}
class TomCat extends Cat implements Moveable
{
}

Cat o = new TomCat();
boolean isCat = o instanceof Cat;
boolean isMoveable = o instanceof Moveable;
boolean isTom = o instanceof TomCat;

Cat o = new Cat();
boolean isCat = o instanceof Cat;
boolean isMoveable = o instanceof Moveable;
boolean isTom = o instanceof TomCat;

Operator instanceof katon kaya iki: a instanceof B .

Ing tembung liyane, operator instanceof bakal bali bener yen:

1) variabel a nyimpen referensi kanggo obyek saka tipe B

2)  variabel a nyimpen referensi kanggo obyek sing kelas warisan  B

3)  variabel a nyimpen referensi menyang obyek sing ngetrapake antarmuka  B

Yen ora, operator instanceof bakal ngasilake false .

"Wis ta. Lha iki kok perlu, Pakdhe Rishi?"

"Ellie arep nyritakake babagan iki dina iki. Iki operator sing apik banget. Sampeyan bakal yakin yen dina iki."