Accepting and Returning Objects when Programming with Methods in Java

In the previous section, we went through only the methods accepting objects as parameters. Now, we shall look at methods returning objects. Modify your code (in “MyCalc.java”) so that it looks something like the following:

  package MyPack;

  /**
   *
   * @author Administrator
   */
  public class MyCalc {

    int x=0;
    int y=0;

    /** Creates a new instance of MyCalc */
    public MyCalc() {
    }

    public void copyValues(MyCalc c) {
        x = c.x;
        y = c.y;
    }

    public MyCalc getDoubledValues() {
        MyCalc t = new MyCalc();
        t.x = x * x;
        t.y = y * y;
        return t;
    }

    public int getSum() {
        int z;
        z = x + y;
        return z;
    }
  }

Now, get back to the frame “test.java.”  Double click on it to open and finally double click on the button to open source view.  Within the source view, modify your “buttonActionPerformed” in such a way that it looks like the following:

private void btnShowActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
        MyCalc obj1 = new MyCalc();
        MyCalc obj2 = new MyCalc();

        obj1.x = 10;
        obj1.y = 20;

        //obj2.copyValues(obj1);
        obj2 = obj1.getDoubledValues();

        int r;
        r = obj1.getSum();
        this.lblMsg.setText("Sum = " + String.valueOf(r));

        r = obj2.getSum();
        this.lblMsg2.setText("Sum = " + String.valueOf(r));

    }        

The next section will give you an explanation for all of the above code.