Question

As an example, I want to mimic the functionality of the String object:

String mystring = new String ( "Hi there." );
System.out.println(mystring); // prints "Hi there." without calling any methods on String
                              // (that is what I want with my object)
System.out.println(mystring.toUpperCase()); // prints "HI THERE."

Starting with this:

class MyObject
{
    private Int value ;

    public MyObject ( Int value )
    {
        this.value = value ;
    }
    public Int getValue ( )
    {
        return this.value ;
    }
    public Int multiplyBy ( Int multiplier )
    {
        return this.value * multiplier ;
    }
}

… How (or can I) do something like this:

MyObject myobject = new MyObject ( 6 ) ;
System.out.println( myobject ) ; // want to print myobject.value (6)
System.out.println( myobject.multiplyBy ( 2 ) ) ; // print 12

I’m quite new to Java and realize that I’m probably missing some fundamental concept, but any feedback would be appreciated. Thank you.

Edit:
The responses about overriding the toString method were helpful, but it’s not quite doing what I had in mind, here’s a better example of what I want:

Double mydouble = new Double ( 20.1 ) ;
System.out.println ( mydouble + 10.1 ) ; // prints 30.2

How would I do this with my own object (assuming I want the default value to be a double)?

Thanks again.

Final Edit (hopefully):
Your answers were enough to lead me to learn more about Primitive Wrappers and Autounboxing. My understanding is that there’s no way to do what I want (which at this point, I would describe as autounboxing my object as a double), or at least I’ll save that for another question. Cheers.

Answer 1

Yes, you can do it: all you need to do is overriding toString:

public String toString() {
    return ""+this.value;
}

This works because println calls toString on objects being printed.