This section explains the input/output methods. To save and read an object in an ILOG JViews formatted file, you need to implement the write method and a constructor that takes an IlvInputStream parameter.

The write Method

The method write writes the colors of the object, the dimensions of the rectangle, and the thickness of the shadow to the provided output stream:

 /**
   * Writes the object to an output stream.
   */ 
  public  void write(IlvOutputStream stream) 
    throws IOException
  {
    // Calls the super class method that will write
    // the fields specific to the super class.
    super.write(stream);
    // Writes the colors.
    stream.write("color", getColor());
    stream.write("shadowColor", getShadowColor());
    // Writes the thickness.
    stream.write("thickness", getThickness());
    // Writes the definition rectangle.
    stream.write("rectangle", drawrect);
  }

The read Constructor

To read a graphic object from a file, you must provide a specific constructor with an IlvInputStream parameter. This constructor must be public to allow the file reader to call it. Also, the constructor must read the same information, and in the same order, as that written by the write method.

 /**
   * Reads the object from an IlvInputStream
   * @param stream the input stream.
   * @exception IlvReadFileException an error occurs when reading.
   */
  public ShadowEllipse(IlvInputStream stream) throws
                                               IlvReadFileException
  {
    // Calls the super class constructor that reads
    // the information for the super class in the file.
    super(stream);
    // Reads the color.
    setColor(stream.readColor("color"));
    // Reads the shadow color.
    setShadowColor(stream.readColor("shadowColor"));
    // Reads the thickness
    setThickness(stream.readInt("thickness"));
    // reads the definition rectangle.
    IlvRect rect = stream.readRect("rectangle");
    drawrect.reshape(rect.x, rect.y, rect.width, rect.height);
  }