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Thread: Drawing a string without use of Main(String[] args)

  1. #1
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    Default Drawing a string without use of Main(String[] args)

    Basically I have this code and another program that rotates text around the screen and I'm trying to merge them. How do I draw a string to this code without the use of something like

    public static void main( String args[] ) //
    { //
    (new ViewOfDisplay()).setVisible(true); // Start application
    }

    I can't change the barebones of the code, just add to

    package Clients;
     
    import java.awt.*;
    import java.awt.event.*;
    import javax.swing.*;
    import javax.swing.event.*;
     
    import java.util.List;
    import java.util.Map;
    import java.util.Observer;
    import java.util.Observable;
     
    import Middle.*;
     
    class ViewOfDisplay implements Observer
    {
      private static final int H = 300;       // Height of window pixels
      private static final int W = 400;       // Width  of window pixels
     
      public ViewOfDisplay( RootPaneContainer rpc )
      {
        // Add code to setup a graphical view of the display
      }
     
     
     
      public void update( Observable aModelOfDisplay, Object arg )
      {
         // Code to update the graphical display with the current
         //  state of the system
         //  Orders awaiting processing
         //  Orders being picked in the 'warehouse. 
         //  Orders awaitig collection
      }
     
     
    }





    This is the rotating text program

    import javax.swing.*;
    import java.awt.*;
    import java.awt.geom.*;
    import java.awt.image.BufferedImage;
     
    // Note Menu bar is at the top of the area 
     
    class Main
    {
      public static void main( String args[] )  // 
      {                                         // 
        (new Application()).setVisible(true);   // Start application 
      }                                         // 
    }
     
    class Application extends JFrame
    {
      private static final int H = 300;         // Height of window 
      private static final int W = 400;         // Width  of window 
     
      private Animate animation;                // Active object 
      private String  message = 
              "Rotating message ";
      private Font font =
           new Font("Monospaced",Font.BOLD,24);
     
      public Application()
      {
        setSize( W, H );                        // Size of drawing area 
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        animation = new Animate();              // Start chimney smoking 
        animation.start();
      }
     
      public void update( Graphics g )          // Called by repaint 
      {                                         // 
        drawScreen( (Graphics2D) g );           // Draw Screen 
      }
     
      public void paint( Graphics g )           // When 'Window' is first 
      {                                         //  shown or damaged 
        drawScreen( (Graphics2D) g );           // Draw Screen 
      }
     
      private Dimension     theAD;              // Alternate Dimension 
      private BufferedImage theAI;              // Alternate Image 
      private Graphics2D    theAG;              // Alternate Graphics 
     
      public void drawScreen( Graphics2D g )    // Double buffer 
      {                                         //  allow resize 
        Dimension d    = getSize();             // Size of image 
     
        if (  ( theAG == null )  ||
              ( d.width  != theAD.width ) ||
              ( d.height != theAD.height ) )
        {                                       // New size 
          theAD = d;
          theAI = (BufferedImage) createImage( d.width, d.height );
          theAG = theAI.createGraphics();
          AffineTransform at = new AffineTransform();
          at.setToIdentity();
          at.scale( ((double)d.width)/W, ((double)d.height)/H );
          theAG.transform(at);
        }
     
        drawActualScreen( theAG );               // Draw actual screen 
        g.drawImage( theAI, 0, 0, this );
      }
     
      public void drawActualScreen( Graphics2D g )// Actual draw screen 
      {
        g.setPaint( Color.white );              // Paint Colour 
        g.fill( new Rectangle2D.Double( 0, 0, W, H ) );
     
        g.setPaint( Color.black );              // Paint Colour 
        g.setFont ( font );
     
        FontMetrics fm = getFontMetrics( font );
        int width = fm.stringWidth(message);
     
        int offset = animation.getPos();
     
        g.drawString( message, offset, 100 );
        g.drawString( message, W + offset, 100 );
      }
     
      class Animate extends Thread
      {
        private int       pos = 1;              // 
     
        public synchronized int getPos()
        {
          return pos;
        }
     
        public synchronized void moveString()   // Move string 
        {
          pos--;                                //  New position 
          if ( pos < -W ) pos = 0;
        }
     
        public void run()                       // Active part 
        {
          while ( true )                        // Forever 
          {                                     // 
            try                                 // 
            {                                   // 
              moveString();                     //  Move mess 
              repaint();                        //   -> update 
              Thread.sleep( 25 );               //  Sleep 
            }                                   // loop 
            catch (InterruptedException e) {}   // Ignore any error 
          }
        }
      }
     
    }


  2. #2
    Super Moderator curmudgeon's Avatar
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    Default Re: Drawing a string without use of Main(String[] args)

    The program needs either an explicit main method or an implicit one (such as with an applet) in order to run. I know of no way around this other than using a static initializer kludge.

  3. #3
    Super Moderator Norm's Avatar
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    Default Re: Drawing a string without use of Main(String[] args)

    @curmudgeon I've lost my example of how to start a class (one without a main() method) using a static initializer using the java command. Could you post a SSCCE for it?
    Thanks.
    If you don't understand my answer, don't ignore it, ask a question.

  4. #4
    Super Moderator curmudgeon's Avatar
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    Default Re: Drawing a string without use of Main(String[] args)

    I think I may be mistaken on that one. I thought that you could get some code up and running from a static initializer block without a main, but on looking into this, I'm not so sure any more.

  5. #5
    Super Moderator pbrockway2's Avatar
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    Default Re: Drawing a string without use of Main(String[] args)

    Maybe they changed something with 7.

    --- Update ---

    According to the (unchanged) documentation for the java executable it "launches a Java application. It does this by starting a Java runtime environment, loading a specified class, and invoking that class's main method".

    So does the following wrok?

    public class Silly {
        static {
            Silly app = new Silly();
            app.displayWhy();
                // We exit before the java executable gets a chance to complain
                // about not finding main()
            System.exit(666);
        }
     
        void displayWhy() {
            System.out.println("Because we can!");
        }
    }

    It's fine in 6 update 26, but results in an error in 7.

  6. The Following 2 Users Say Thank You to pbrockway2 For This Useful Post:

    curmudgeon (December 17th, 2012), Norm (December 18th, 2012)

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