How to access data members from another class..

[Code_Nerd]

I am trying to access private data members from one class in another class..
eg: Trying to use a print() method in one class and trying to access the data members with getID()..

However this throws and error "Non static method cannot be referenced from static context.."

What have I done wrong and how could I correct it? Code snippets below..

Part of my print()

public void inorderPrint()
                {
                    if (left != null)
                        left.inorderPrint( );
                    System.out.print(CD.getID()+"\t");
                    if (right != null)
                        right.inorderPrint( ); }

Part of my CD class

public class CD {
                private int ID;
                private String artist;
                private String title;
                private String company;
    
    /** Creates a new instance of CD */
    public CD(int id, String ar, String ti, String co)
    { 
        ID = id;
        artist = ar;
        title = ti;
        company = co; 
    }
public int getID()
    { return ID; }
    
    public String getArtist()
    { return artist; }
    
    public String getTitle()
    { return title; }
    
    public String getCompany()
    { return company; }
}

Thankyou for your time..

[sjalle]

I see one suspicious line in the inorderPrint()

System.out.print(CD.getID()+"\t");

you cannot use the CD class' getID method like it was a static method,
and if you think of it, what id should that method return ?

[Code_Nerd]

Thankyou for your reply..
That is what I am having problems with, how to access the members of the CD class in my BTNode class?

[sjalle]

If you have two classes ClassA and ClassB and you want ClassB to invoke
non-static methods in ClassA then ClassB must have access to an instance of
ClassA. You can do this many ways but two of them are:
1: ClassB has a constructor that takes an instance of ClassA
2: ClassB has a method, e.g. setClassA(ClassA aClass), that supplies it
with an instance of ClassA.

So, using method 1:

ClassA aClass=new ClassA();
ClassB bClass=new ClassB(aClass);

A part of ClassB:

private ClassA aClass=null;
private int id=-1;

// constructor
public ClassB(ClassA aClass) {
  this.aClass=aClass;
}
public void someBMethod() {
  this.id=aClass.getID(); // invoke a ClassA method
}

[Code_Nerd]

Thankyou for your help..

I now have the problem sorted!

Cheers