/** 
  * Passband Demonstrator
  * @author Robert J Morton UK-YE572246C
  * @version 25 November 2001 revamped November 2007
  * Converted to a JFramed application  Thu 15 March 2018  */

/* Open a terminal and change directory to where this file is loacated.
   To compile this program, enter the terminal command:

   javac passband_start.java

   To run this program, enter the terminal command: java passband_start */

import javax.swing.*;
import java.awt.Dimension;  // to be able to set the preferred JFrame size
import java.awt.Color;      // to be able to set JFrame background colour


public class passband_start extends JFrame {

  private static final long 
    serialVersionUID = 4448L;  // what the hell this is for, I don't know!

  private int
    XE = 302,  // Horizontal extent of window and JFrame.
    YE = 290;  // Vertical extent of window and JFrame.

  /* Declare a reference to an instance of the child class. Beware:
  an instance of the child class cannot be created here because this 
  must be done within the invokeAndWait environment. */
  private passband LG; 


  private passband_start() {  // construct an instance of this extended JFrame

    //set window frame title on title bar
    super("Tuned Circuit Attenuation Function Generator");

    /* Set up the window listener to listen for the window close command which
    occurs when the user clicks on the X control in the window's title bar.*/
    setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

    /* Set the initial size of the extended JFrame. This is the area INSIDE 
    the frame. It does not include the border or the title bar areas. */
    setPreferredSize(new Dimension(XE, YE));

    setBounds(0,0,XE,YE);        // of area inside window frame
    setBackground(Color.black);  // default background colour of JFrame
    LG = new passband();         // new instance of passband_start class
    getContentPane().add(LG);    // add it to the extended JFrame's pane.
    pack();                      // should automatically pack to fill JFrame
    setVisible(true);            // make this extended JFrame visible
  }


  public static void main(final String[] args) {

    /* Initiate the creation of a new instance of this extended JFrame
    and then wait until the building process has completely finished
    before giving the new instance of the child class permission to
    commence running. */

    try {
      javax.swing.SwingUtilities.invokeAndWait(
        new Runnable() { public void run() { new passband_start(); } }
      );
    } catch(Exception e) {
      System.out.println("Couldn't create Swing GUI.");
      System.out.println("There's probably an error in the constructor");
      System.out.println("code of one of this class's child classes.");
      System.out.println(e);
      System.out.println(e.getCause()); 
    }

    /* The above try-catch sequence is necessary for the following reason. 
    The statement "new passband_start();" is a request to Swing to create
    a GUI instance of this application. It includes, in effect, all the
    statements in the constructor methods of all this class's child classes.
    All these requests are made on this, the main() program thread. 

    However, these requests are carried out [ie the actual constructing is 
    done] by the underlying Swing system on the Event Despatching Thread. 
    The constructing process necessarily takes longer to do than the mere
    task of REQUESTING that the constructing be done. This means that the
    main() thread will set the run() thread in motion before the GUI has 
    finished being constructed. Hence trouble.

    The solution is to force the main() thread to withhold permission for 
    the run() thread to start its job until the Event Despatching Thread 
    has completely finished constructing the GUI. */

    /* NOTE: This class inherits a paint() method from the JFrame class that 
    it extends. This method automatically calls the paint() method of the
    child [extended JPanel] class when necessary. */

  }  // end of main()

}    // end of passband_start class