question about programming

Question

What does it mean when you are asked to create a method that will accept one time objects and return true if the two times are the same and false otherwise?

Answer 1

Sounds like you are talking about a Singleton class...

class where there is only one instance.

This is used typically in software drivers, databases, etc where there

is only one instance of the device: printer, monitor, remote, etc

here is some code I found online.

// Java program implementing Singleton class

// with getInstance() method

class Singleton

{

// static variable single_instance of type Singleton

private static Singleton single_instance = null;

// variable of type String

public String s;

// private constructor restricted to this class itself

private Singleton()

{

s = "Hello I am a string part of Singleton class";

}

// static method to create instance of Singleton class

public static Singleton getInstance()

{

if (single_instance == null)

single_instance = new Singleton();

return single_instance;

}

}

// Driver Class

class Main

{

public static void main(String args[])

{

// instantiating Singleton class with variable x

Singleton x = Singleton.getInstance();

// instantiating Singleton class with variable y

Singleton y = Singleton.getInstance();

// instantiating Singleton class with variable z

Singleton z = Singleton.getInstance();

// changing variable of instance x

x.s = (x.s).toUpperCase();

System.out.println("String from x is " + x.s);

System.out.println("String from y is " + y.s);

System.out.println("String from z is " + z.s);

System.out.println("\n");

// changing variable of instance z

z.s = (z.s).toLowerCase();

System.out.println("String from x is " + x.s);

System.out.println("String from y is " + y.s);

System.out.println("String from z is " + z.s);

}

}