Chapter 6 notes

Important stuff:
220 Math table
221,2 ff.
6.8 (most important in chapter)
6.10
6.11
254-6 line 28, p.256 1st para.

Math class static methods:  always: Math.method_name
Math.sqrt(x*x+y*y)
2 * Math.PI * radius


type promotion/coercion:
"little" to "big" OK  e.g. int to float
"big" to "little" syntax error: e.g. double to float.  (cast) needed
int i;  double d;
d = i;  //OK
i = d;  //syntax error.  allowable in C++
i = Math.sqrt(x);   //syntax error.  sqrt returns double
i = (int)Math.sqrt(x);  //OK


java.awt.Container;       //GUI components can be attached to a Container
Container mycontainer = getContentPane();   //no new.  content pane of applet
mycontainer.add(a_GUI_component_ref)  //add a GUI object to the
                                      //applet's content pane


java.awt.FlowLayout;   //simplest layout manager.  left to right, top to bottom
java.awt.event.ActionEvent;  //info about the action that occurred
java.awt.event.ActionListener;  //Interface

public class MyCoolApp extends JApplet implements ActionListener {

JLabel mylabel = new JLabel(String)

JTextField mytext = new JTextField(int size)
mytext.setEditable(false)       //display only, no input
mytext.setText(String)          //assign text
mytext.getText()        //returns String

JButton mybutton = new JButton(String)
//this applet has the event handler (it implements the actionPerformed
//method of the ActionListener interface:
mybutton.addActionListener(this)

Container mycontainer = getContentPane()
//a FlowLayout object will be the layout manager for this container:
mycontainer.setLayout(new FlowLayout())
mycontainer.add(JLabel ref)
mycontainer.add(JTextField ref)
mycontainer.add(JButton ref)
mycontainer.add(JTextArea ref)

showStatus(String)      //set the status bar

//event handler for registered event:
public void actionPerformed(ActionEvent ae) {
...


javax.swing.:
  JOptionPane
  JTextArea
  JScrollPane
  JApplet
  JLabel
  JTextField
  JButton


Method Overloading.
methods with same name but arguments differ in number, types, order.
return type irrelevant.
int  f(int)
int  f(float)
void f(int,float)
void f(float,int)
int  f(int,float)   //syntax error
int  f(String)
void f(String)      //syntax error
void f(int, float, int)