Beginning of the end - reading and writing to a file

[Kieran Murray]

Dear Ranchers,

I can not understand why I am getting this exception when I read in a file.

Exception:translation.Generator; translation.Generator; no valid constructor

The code to write the object is below

 
  try
 {
FileOutputStream fos = new FileOutputStream(file);
        ObjectOutputStream Object = new ObjectOutputStream(fos);
Object.writeObject(Drawing.ZoomPanel.genpaths);
Object.flush();
Object.close();
 }
 catch(Exception ex)
 {
System.out.println("Exception:" + ex);
 return false;
 }
 
return true;  
  }
 

The code to read in is

 try{
  
FileInputStream fis = new FileInputStream(file);
ObjectInputStream ois = new ObjectInputStream(fis);

        ArrayList readinvalue4 = (ArrayList)ois.readObject();
  fis.close();
 
}
 

Then I repaint the object taken in

int genpathSize = readinvalue4.size();
 
   for(xcount=0;xcount<=genpathSize-1; xcount++)
                        {
                           Object  pp = readinvalue4.get(x);
                           Drawing.ZoomPanel.genpaths.add(pp);
                           
                        }
                        
                        Drawing.ZoomPanel.repaint();
 

The paint method is below

 protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D)g;
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                            RenderingHints.VALUE_ANTIALIAS_ON);
       
        for(int j = 0; j < genpaths.size(); j++) {
            path1 = (Generator) genpaths.get(j);
            
            Path2D.Double shpnew = ((Generator) path1).getShape();
           
           newcolour = path1.getColour();
            // Since you want to move all paths uniformly we
            // can use a transform to keep track of them.
            g2.setPaint(newcolour);
            Shape s = at.createTransformedShape(shpnew);
            g2.setStroke(new BasicStroke(2.0f));
            g2.draw(s);
        }

the Generator class is below
[code]
package translation;

import java.awt.geom.*;
import java.awt.Color;
import java.awt.Shape;


public class Generator extends Shapes{

final String name = "Generator";
Color colour;

Path2D.Double shp = new Path2D.Double();

{
shp.moveTo(200.0f/5, 220.0f/5); //start point
shp.curveTo(130/5, 220/5, 130/5, 320/5, 200/5, 320/5);
shp.curveTo(150/5, 260/5, 250/5, 280/5, 200/5, 220/5);

shp.moveTo(200.0f/5, 220.0f/5);

shp.curveTo(270/5, 220/5, 270/5, 320/5, 200/5, 320/5);
shp.lineTo(200.0/5,400.0/5);
}

public Generator()
{
}

public Path2D.Double getShape()
{
return shp;
}

public void setColor(Color colour)
{
this.colour = colour;
}

public Color getColour()
{
return colour;
}

public String getName()
{
return this.name;
}
}

Kind regards

Kieran

[Kieran Murray]

Dear Ranchers,

I have managed to solve the problem. I changed the Shapes class to an extension of a JComponent rather than an extension of a Path2D.Double.
This may have consequences down the line - who knows.
I did this after reading the evaluation in this Sun bug database. It talks about Arc2D.Double and I thought this might be applicable to Path2D.Double.

http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6522514

Anyway - I did not understand the ins and outs of serialisation - any explanations most welcome.

The solution was quick and dirty - but it works .

Thanks,

Kieran