Name: tb29552 Date: 06/18/97


Compiling the given source code hangs the compiler (no output,
no nothing!). Will stay hung for hours.

Additional classes can be provided upon request.

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import java.awt.*;
import java.awt.event.*;
import java.util.*;
import java.io.*;

class DiagramComponent extends Canvas implements Serializable
{
  Vector views;
  boolean tracking, sized;
  int dX, dY, cViews;
  FontMetrics fm;
  ClasView selected;

  public DiagramComponent()
  {
    views = new Vector();
    tracking = false;
    selected = null;
    sized = false;

    cViews = 1;

    addMouseListener( new MouseAdapter() {

      public void mousePressed( MouseEvent e ) {

int x = e.getX();
int y = e.getY();

boolean foundOne = false;

for ( int i = views.size() - 1; i >= 0; i-- ) {
ClasView cv = (ClasView) views.elementAt(i);

if ( cv.contains( x, y ) ) {
select( cv );

foundOne = true;
break;
}
}

if ( !foundOne ) {
if ( selected != null ) unselect( selected );
}
else {
tracking = true;

dX = selected.x - x;
dY = selected.y - y;

repaint( selected.x, selected.y, selected.width, selected.height );
}
      }

      public void mouseReleased( MouseEvent e ) {

if ( tracking ) {
tracking = false;
}
      }
    } );

    addMouseMotionListener( new MouseMotionAdapter() {
      
      public void mouseDragged( MouseEvent e ) {

int x = e.getX();
int y = e.getY();

if ( tracking && selected != null ) {
Rectangle old = selected.bounds();
Rectangle vGap, hGap;

selected.setLocation( x + dX, y + dY );

Graphics g = getGraphics( );

g.copyArea( old.x, old.y, old.width, old.height, (selected.x - old.x),
( selected.y - old.y ) );
      
g.dispose();

vGap = new Rectangle( );

vGap.x = ( selected.x < old.x ) ? selected.x + selected.width : old.x;
vGap.y = ( selected.y < old.y ) ? selected.y : old.y;

vGap.width = Math.abs( selected.x - old.x );
vGap.height = Math.abs( selected.y - old.y ) + selected.height;

hGap = new Rectangle( );

hGap.x = ( selected.x < old.x ) ? selected.x : old.x;
hGap.y = ( selected.y < old.y ) ? selected.y + selected.height : old.y;

hGap.width = selected.width;
hGap.height = Math.abs( selected.y - old.y );

repaint( vGap.x, vGap.y, vGap.width, vGap.height );
repaint( hGap.x, hGap.y, hGap.width, hGap.height );
}
      }
    } );

  }
    
  public void addNewClas( String newName )
  {
    Clas theClas = new Clas( newName );
    ClasView cv = new ClasView( theClas );

    views.addElement( cv );

    if ( sized )
    {
      cv.resize( cv.size( fm ) );

      Dimension sz = getSize();
      Dimension vsz = cv.size();
      
      cv.setLocation( ( sz.width - vsz.width ) / 2, ( sz.height - vsz.height ) / 2 );

      repaint( cv.x, cv.y, cv.width, cv.height );
    }

    select( cv );
  }
  
  public void addNewClas( )
  {
    addNewClas( "Class" + cViews++ );
  }
  
  public void delete( )
  {
    if ( selected != null )
    {
      ClasView cv = selected;

      unselect( cv );
      
      views.removeElement( cv );

      repaint( cv.x, cv.y, cv.width, cv.height );
    }
  }
   
  public void paint( Graphics g )
  {
    if ( !sized )
    {
       getSizes( g );
       sized = true;
    }
    
    Rectangle clip = g.getClipBounds();

    for ( int i = 0; i < views.size(); i++ )
    {
      ClasView cv = (ClasView) views.elementAt( i );

      if ( cv.intersects( clip ) )
      {
        g.translate( cv.x, cv.y );

        cv.paint( g );

        g.translate( -cv.x, -cv.y );
      }
    }
  }

  private void getSizes( Graphics g )
  {
    fm = g.getFontMetrics();

    for ( Enumeration e = views.elements(); e.hasMoreElements(); )
    {
      ClasView cv = (ClasView) e.nextElement();
      
      cv.resize( cv.size( fm ) );
    }
  }

  private void select( ClasView cv )
  {
    if ( selected != null ) unselect( selected );

    selected = cv;
    
    views.removeElement( cv );
    views.addElement( cv );

    cv.selected = true;
  }

  private void unselect( ClasView cv )
  {
    cv.selected = false;
    selected = null;
    repaint( cv.x, cv.y, cv.width, cv.height );
  }

}



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