[java] Why is clone protected?

You''ll need to create a method in Shape something like:

public Shape cloneShape()
{
Shape testShape = new Shape();
testShape = this.clone();
return(testShape);
}

then call s.cloneShape();


Protected methods can''t be accessed by anything other than subclasses...

I''m just guessing here, but I noticed a possible error in your code:

Rect rectCopy = (Rect)s.clone();

Shouldn''t this be like:

Rect rectCopy = ((Rect)s).clone();

?

because clone() can be prone to abuse.

Imagine you have your class (let''s call it One), and you have reference to other classes (Two, and Three). If you clone One, ¿would you have to clone also Two and Three?, or the clone would have the same references to the original Two and Three?

In order to clone an object, you have two options:

1) A constructor which unique parameter is an object of the same class, and in the constructor you assign the instance variables...

public One(One otherClass) {
this.firstVariable = otherClass.firstVariable;
this.secondVariable = otherClass.secondVariable;
//and so on...
}

2) Make a public cloning method which returns the clone of the object (Warning: you have to tag first the class by implementing the Cloneable interface)

class One implements Cloneable {
//bla bla bla
public One cloneOne() {
return this.clone();
}//more bla bla bla
}
I''m a bit sleepy, and too lazy to check this, if any errors, sorry

First, correct a few posters.

* A protected method/field is accessible to any subclasses *and* to any classes in the same package.

* (Rect) s.clone() is what was meant and is correct.

Now, a couple of suggestions,

Are you actually defining your own clone() method for Rect?? I''m not clear on this point but this might explain your problem. The clone() method that will actually be called will lie in the java.lang package, whereas your error is in a class in (presumably) the default package.

Or, is Rect in a different package to the line generating there error?

Jiim Jonez
www.javage.net